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Non-small cell lung cancer (NSCLC) is a major disease with high incidence, low survival rate and prone to develop drug resistance to chemotherapy. The mechanism of secondary drug resistance in NSCLC chemotherapy is very complex, and studies have shown that the abnormal activation of STAT3 (Signal Transducer and Activator of Transcription 3) plays an important role in it. In this study, the pGPU6/GFP/Neo STAT3-shRNA recombinant plasmid was constructed with STAT3 as the precise target. By modifying hydrophilic and hydrophobic blocks onto chitosan, a multifunctional vitamin E succinate-chitosan-polyethylene glycol monomethyl ether histidine (VES-CTS-mPEG-His) micelles were synthesized. The micelles could encapsulate hydrophobic drug doxorubicin through self-assembly, and load the recombinant pGPU6/GFP/Neo STAT3-shRNA (pDNA) through positive and negative charges to form dual-loaded nanoparticles DOX/VCPH/pDNA. The co-delivery and synergistic effect of DOX and pDNA could up-regulate the expression of PTEN (Phosphatase and Tensin Homolog), down-regulate the expression of CD31, and induce apoptosis of tumor cells. The results of precision targeted therapy showed that DOX/VCPH/pDNA could significantly down-regulate the expression level of STAT3 protein, further enhancing the efficacy of chemotherapy. Through this study, precision personalized treatment of NSCLC could be effectively achieved, reversing its resistance to chemotherapy drugs, and providing new strategies for the treatment of drug-resistant NSCLC.

ABSTRACTOxidative stress (OS) has been considered as the main mediator of male infertility by causing abnormal sperm production and function, and, therefore, exploration of natural antioxidant has attracted a great deal of attention in human reproduction. Chitosan and its derivatives exhibit great antioxidant potential in various diseases, whereas the protective functions are not defined in spermatogenesis. Here, we show that chitosan oligosaccharide (COS), a degradation product of chitosan with a degree of polymerization of less than 10, is a strong antioxidant in spermatogonia cells. COS treatment reduces t-BHP-induced reactive oxygen species overproduction and programmed necrosis in GC-1 spg cells, and improves mitochondrial functions and cell viability by inhibiting excessive endoplasmic reticulum stress. Our findings provide novel insight into the protective role of COS in germ cell damage.

Brucellosis is a zoonotic infectious disease that has long endangered the development of animal husbandry and human health. Currently, vaccination stands as the most efficacious method for preventing and managing brucellosis. Alum, as the most commonly used adjuvant for the brucellosis vaccine, has obvious disadvantages, such as the formation of granulomas and its non-degradability. Therefore, the aims of this study were to prepare an absorbable, injectable, and biocompatible hydroxypropyl chitin (HPCT) thermosensitive hydrogel and to evaluate its immunization efficacy as an adjuvant for Brucella antigens. Specifically, etherification modification of marine natural polysaccharide chitin was carried out to obtain a hydroxypropyl chitin. Rheological studies demonstrated the reversible temperature sensitivity of HPCT hydrogel. Notably, 5 mg/mL of bovine serum albumin can be loaded in HPCT hydrogels and released continuously for more than one week. Furthermore, the L929 cytotoxicity test and in vivo degradation test in rats proved that an HPCT hydrogel had good cytocompatibility and histocompatibility and can be degraded and absorbed in vivo. In mouse functional experiments, as adjuvants for Brucella antigens, an HPCT hydrogel showed better specific antibody expression levels and cytokine (Interleukin-4, Interferon-γ) expression levels than alum. Thus, we believe that HPCT hydrogels hold much promise in the development of adjuvants.

AbstractAcute kidney injury (AKI) and renal interstitial fibrosis are global clinical syndromes associated with high morbidity and mortality. Renal ischemia-reperfusion (I/R) injury, which commonly occurs during surgery, is one of the major causes of AKI. Nevertheless, an efficient therapeutic approach for AKI and the development of renal interstitial fibrosis is still lacking due to its elusive pathogenetic mechanism. Here, we showed that chitosan oligosaccharide (COS), a natural oligomer polysaccharide degraded from chitosan, significantly attenuates I/R-induced AKI and maintains glomerular filtration function by inhibiting oxidative stress, mitochondrial damage, and excessive endoplasmic reticulum stress both in vitro and in vivo. In addition, long-term administration of COS can also attenuate the proliferation of myofibroblasts, mitigate extra cellular matrix deposition, and thus inhibit the transition of AKI to chronic kidney disease through participating in metabolic and redox biological processes. Our findings provide novel insights into the protective role of COS against acute kidney injury.

Postmenopausal osteoporosis is the most common type of osteoporosis. Chondroitin sulfate (CS) has been successfully employed as food supplement against osteoarthritis, while the therapeutic potential on postmenopausal osteoporosis is little explored. In this study, CS oligosaccharides (CSOs) were enzymatically prepared through the lysis of CS by a chondroitinase from Microbacterium sp. Strain. The alleviating effects of CS, CSOs and Caltrate D (a clinically used supplement) on ovariectomy (OVX) ‐ induced rat’s osteoporosis were comparatively investigated. Our data showed that the prepared CSOs was basically unsaturated CS disaccharide mixture of ∆Di4S (53.1%), ∆Di6S (27.7%) and ∆Di0S (17.7%). 12 weeks’ intragastric administration of Caltrate D (250 mg/kg/d), CS or CSOs (500 mg/kg/d, 250 mg/kg/d, 125 mg/kg/d) could obviously regulate the disorder of serum indices, recover the mechanical strength and mineral content of bone, improve the cortical bones’ density and the number and length of trabecular bones in OVX rats. Both CS and CSOs in 500 mg/kg/d and 250 mg/kg/d could restore more efficiently the serum indices, bone fracture deflection and femur Ca than Caltrate D. As compared with CS at the same dosage, CSOs exhibited a more significant alleviating effect. These findings suggested that there was great potential of CSOs as daily interventions for delaying the progression of postmenopausal osteoporosis.

Improving the degree of vascularization through the regulation of wound microenvironment is crucial for wound repair. Gene activated matrix (GAM) technology provides a new approach for skin regeneration. It is a local gene delivery system that can not only maintain a moist environment, but also increase the concentration of local active factors. For this purpose, we fabricated the mVEGF165/TGF-β1 gene-loaded N-carboxymethyl chitosan/sodium alginate hydrogel and studied its effect on promoting deep second degree burn wound repair. The average diameter of the hydrogel pores was 100 μm and the porosity was calculated as 50.9%. SEM and CLSM images showed that the hydrogel was suitable for cell adhesion and growth. The NS-GAM could maintain continuous expression for at least 9 days in vitro, showing long-term gene release and expression effect. Deep second-degree burn wound model was made on the backs of Wistar rats to evaluate the healing effect. The wounds were healed by day 22 in NS-GAM group with the prolonged high expression of VEGF and TGF-β1 protein. A high degree of neovascularization and high expression level of CD34 were observed in NS-GAM group in 21 days. The histological results showed that NS-GAM had good tissue safety and could effectively promote epithelialization and collagen regeneration. These results indicated that the NS-GAM could be applied as a promising local gene delivery system for the repair of deep second-degree burn wounds.

Nanocarriers have emerged as a promising cancer drug delivery strategy. Multi-drug resistance caused by overexpression of multiple-drug excretion transporters in tumor cells is the major obstacle to successful chemotherapy. Vitamin E derivatives have many essential functions for drug delivery applications, such as biological components that are hydrophobic, stable, water-soluble enhancing compounds, and anticancer activity. In addition, vitamin E derivatives are also effective mitocan which can overcome multi-drug resistance by binding to P glycoproteins. Here, we developed a carboxymethyl chitosan/vitamin E succinate nano-micellar system (O-CMCTS-VES). The synthesized polymers were characterized by Fourier Transform IR, and 1H NMR spectra. The mean sizes of O-CMCTS-VES and DOX-loaded nanoparticles were around 177 nm and 208 nm. The drug loading contents were 6.1%, 13.0% and 10.6% with the weight ratio of DOX to O-CMCTS-VES corresponding 1:10, 2:10 and 3:10, and the corresponding EEs were 64.3%, 74.5% and 39.7%. Cytotoxicity test, hemolysis test and histocompatibility test showed that it had good biocompatibility in vitro and in vivo. Drug release experiments implied good pH sensitivity and sustained-release effect. The DOX/O-CMCTS-VES nanoparticles can be efficiently taken up by HepG2 cancer cells and the tumor inhibition rate is up to 62.57%. In the in vivo study by using H22 cells implanted Balb/C mice, DOX/O-CMCTS-VES reduced the tumor volume and weight efficiently with a TIR of 35.58%. The newly developed polymeric micelles could successfully be utilized as a nanocarrier system for hydrophobic chemotherapeutic agents for the treatment of solid tumors.

Chemotherapy-induced intestinal mucositis (CIM) is a major dose-limiting side effect of chemotherapy, especially in regimens containing irinotecan (CPT-11). Several studies on the pathologic mechanisms of CIM focused on both the genomics and molecular pathways triggered by chemotherapy. However, systematic evaluation of metabolomic analysis in irinotecan-induced intestinal mucositis (IIM) has not been investigated. This study aimed to comprehensively analyze metabolite changes in main tissues of IIM mouse models. Male ICR mice were assigned to two groups: the model group (n = 11) treated with CPT-11 (20 mg/kg daily; i.p.) and the control group (n= 11) with solvent for 9 days. Gas chromatography-mass spectrometry (GC-MS) was used to investigate the metabolic alterations in the serum, intestinal, colonic, hepatic, and splenic samples of mice between two groups by multivariate statistical analyses, including GC–MS data processing, pattern recognition analysis, and pathway analysis. Forty-six metabolites, including hydrocarbons, amino acids, lipids, benzenoids, hydroxy acids, and amines, had significant changes in levels in tissues and sera of IIM mouse models. The most important pathways related to the identified metabolites were the glycerolipid metabolism in the colon and aminoacyl-tRNA biosynthesis; glycine, serine, and threonine metabolism; and glyoxylate and dicarboxylate metabolism in the liver. Our study firstly provided a comprehensive and systematic view of metabolic alterations of IIM using GC-MS analysis. The characterizations of metabolic changes could offer profound and theoretical insight into exploring new biomarkers for diagnosis and treatment of IIM.

Bone defects, a common orthopedic problem in clinical practice, are a serious threat to human health. As alternative materials to autologous bone grafts, synthetic cell-free functionalized scaffolds have been the focus of recent research in designing scaffolds for bone tissue engineering. Butyryl chitin (BC) is a derivative of chitin (CT) with improved solubility. It has good biocompatibility, but few studies have investigated its use in bone repair. In this study, BC was successfully synthesized with a degree of substitution of 2.1. BC films were prepared using the cast film method and showed strong tensile strength (47.8 ± 4.54 N) and hydrophobicity (86.4 ± 2.46°), which was favorable for mineral deposition. An in vitro cytological assay confirmed the excellent cell attachment and cytocompatibility of the BC film; meanwhile, in vivo degradation indicated the good biocompatibility of BC. Hydroxyapatite (HA), extracted from bovine cancellous bone, had good cytocompatibility and osteogenic induction activity for the mouse osteoblast cell line MC3T3-E1. With the aim of combining the advantages of BC and HA, a BC–HA composite scaffold, with a good pore structure and mechanical strength, was prepared by physical mixing. Administered into skull defects of rats, the scaffolds showed perfect bone-binding performance and effective structural support, and significantly promoted the regeneration of new bone. These results prove that the BC–HA porous scaffold is a successful bone tissue engineering scaffold and has strong potential to be further developed as a substitute for bone transplantation.

Melanin is a biological pigment formed by indoles and phenolic compounds. It is widely found in living organisms and has a variety of unique properties. Due to its diverse characteristics and good biocompatibility, melanin has become the focus in the fields of biomedicine, agriculture, the food industry, etc. However, due to the wide range of melanin sources, complex polymerization properties, and low solubility of specific solvents, the specific macromolecular structure and polymerization mechanism of melanin remain unclear, which significantly limits the further study and application of melanin. Its synthesis and degradation pathways are also controversial. In addition, new properties and applications of melanin are constantly being discovered. In this review, we focus on the recent advances in the research of melanin in all aspects. Firstly, the classification, source, and degradation of melanin are summarized. Secondly, a detailed description of the structure, characterization, and properties of melanin is followed. The novel biological activity of melanin and its application is described at the end.

Chitosan (CTS) has been used as a nerve guidance conduit (NGC) material for bridging peripheral nerve defects due to its biocompatible, biodegradable, and non-toxic properties. However, the nerve regeneration effect of chitosan alone is restricted due to its inadequate biological activity. Herein, a composite, bioactive chitosan based nerve conduit, consisting of outer warp-knitted tube scaffold made from medical-grade chitosan fiber, and inner porous cross linked carboxymethyl chitosan (C-CM-CTS) sponge with radial texture was developed. The inner wall of the scaffold was coated with C-CM-CTS solution. CM-CTS provided favorable bioactivities in the composite chitosan-based nerve conduit. An in vitro study of CM-CTS revealed its satisfying biocompatibility with fibroblast and its inhibition of oxidative damage to Schwann cells. As the internal filler of the NGC, the lyophilized sponge of C-CM-CTS showed a longitudinal guidance effect for nerve reconstruction. After 10 mm defect in rat sciatic nerve was bridged with the composite bioactive chitosan-based nerve conduit, the nerve conduit was able to effectively promote axonal regeneration and played a positive role in inducing nerve regeneration and functional recovery. In addition to the functional advantages, which are equal to those of an autograft; the technology for the preparation of this conduit can be put into mass production.

Cancer is considered to have an adverse influence on health around the world. Chitosan, a linear polysaccharide that contains copolymers of β-1-4 linked d-glucosamine and N-acetyl-d-glucosamine units, has been widely used in the field of biomedicine, owing to its nontoxicity, biocompatibility, biodegradability, and hemocompatibility. This study was aimed at preparing the chitosan oligosaccharides (COS) and examining its ability on suppressing lung cancer in vitro and in vivo. Human non-small-cell lung cancer A549 cells model and C57BL/6 mice bearing lung cancer model were adopted. COS showed inhibition on the viability and proliferation of lung carcinoma cells (A549) in time-dependent manners, but no cytotoxicity to human liver cell (HL-7702). Moreover, COS could significantly increase Bax expression of A549 cells while decreasing Bcl-2 expression. COS supplementation significantly inhibited the growth of Lewis tissues and promoted necrosis of tumor cells in vivo. After treatment with COS, significantly elevated concentrations of Bax and reduced expression of Bcl-2 in tumor tissues, as well as elevated levels of TNF-α, IL-2, Fas and Fas-L in mice serum were observed (p < 0.05). In conclusion, COS had certain anti-tumor effects and potential application as a synergic functional food ingredient to prevent cancer.

Postmenopausal osteoporosis has seriously affected the life quality of elderly women. A natural polymer, chitin, obtained from shells of crab and shrimp, has been widely used in the biomedical field owing to its nontoxicity, biocompatibility, and biodegradability. In this study, natural N-acetyl-d-glucosamine (NAG) was prepared from liquefied chitin. The protective activities of NAG in postmenopausal osteoporosis were evaluated on Sprague Dawley rats and osteoblast-based models. Results showed that oral administration of NAG boosted trabecular bone volume and trabecular numbers. Additionally, the calcium content in the femur and tibia increased, and femoral biomechanical properties improved. Furthermore, NAG supplementation significantly lowered alkaline phosphatase levels and increased calcium content in the serum of ovariectomized rats. In vitro studies showed that NAG markedly promoted cell proliferation and stimulated osteoblast differentiation of mouse calvaria origin MC3T3-E1 cells with increased alkaline phosphatase activity in a concentration-dependent manner. Moreover, NAG effectively protected osteoblasts from oxidative damage induced by hydrogen peroxide. In conclusion, our data provide an additional foundation for dietary supplementation of NAG, which could protect and reverse osteopenia in postmenopausal women.

Chitosanase is able to specifically cleave ß-1,4-glycosidic bond linkages in chitosan to produce a chito-oligomer product, which has found a variety of applications in many areas, including functional food and cancer therapy. Although several structures for chitosanase have been determined, the substrate-binding mechanism for this enzyme has not been fully elucidated because of the lack of a high-resolution structure of the chitosanase- substrate complex. In the present study we show the crystal structure of a novel chitosanase OU01 from Microbacterium sp. in complex with its substrate hexa-glucosamine (GlcN)6, which belongs to the GH46 (glycoside hydrolyase 46) family in the Carbohydrate Active Enzymes database (http://www.cazy.org/). This structure allows precise determination of the substratebinding mechanism for the first time. The chitosanase-(GlcN)6 complex structure demonstrates that, from the -2 to +1 position of the (GlcN)6 substrate, the pyranose rings form extensive interactions with the chitosanase-binding cleft. Several residues (Ser27, Tyr37, Arg45, Thr58, Asp60, His203 and Asp235) in the binding cleft are found to form important interactions required to bind the substrate. Site-directed mutagenesis of these residues showed that mutations of Y37F and H203A abolish catalytic activity. In contrast, the mutations T58A and D235A only lead to a moderate loss of catalytic activity, whereas the S27A mutation retains ~80% of the enzymatic activity. In combination with previous mutagenesis studies, these results suggest that the -2, -1 and +1 subsites play a dominant role in substrate binding and catalysis. DSF (differential scanning fluorimetry) assays confirmed that these mutations had no significant effect on protein stability. Taken together, we present the first mechanistic interpretation for the substrate (GlcN)6 binding to chitosanase, which is critical for the design of novel chitosanase used for biomass conversion. [ABSTRACT FROM AUTHOR]

novel chitosan-based membrane that made of hydroxyethyl chitosan, gelatin and chondroitin sulfate was used as a carrier of corneal endothelial cells. The characteristics of the blend membrane including transparency, equilibrium water content, ion and glucose permeability were determined. The results showed that the optical transparency of the membrane was as good as the natural human cornea. The water content of this scaffold was 81.32% which was remarkably close to the native cornea. The membrane had a good ion permeability and its glucose permeability was even higher than natural human cornea. The cultured rabbit corneal endothelial cells formed a monolayer on the membrane. The results demonstrated that the membrane was suitable for corneal endothelial cells to attach and grow on it. In addition, the membranes in vivo could be degraded steadily with less inflammation and showed a good histocompatibility. These results demonstrated that the hydroxyethyl chitosan-chondroitin sulfate-gelatin blend membrane can potentially be used as a carrier for corneal endothelial cell transplantation. [ABSTRACT FROM AUTHOR]

A novel chitosan-based membrane that was made of hydroxypropyl chitosan, gelatin and chondroitin sulfate was used as a carrier of corneal endothelial cells. The characteristics of the blend membrane, such as transparency, equilibrium water content, permeability, mechanical properties, protein absorption ability, hydrophilicity and surface morphology, were determined. To study the effects of the membrane on cell attachment and growth, rabbit corneal endothelial cells were cultured on this artificial membrane. The biodegradability and biocompatibility of the blend membrane were in vivo evaluated by its implantation into the muscle of the rats. Glucose permeation results demonstrated that the blend membrane had higher glucose permeability than natural human cornea. Scanning electron microscopy (SEM) analysis of the membranes demonstrated that no fibrils were observed. As a result, the optical transparency of the membrane was as good as the natural human cornea. The average value of tensile strength of the membrane was 13.71 MPa for dry membrane and 1.48 MPa for wet membrane. The value of elongation at break of the wet was 45.64%. The cultured rabbit corneal endothelial cells formed a monolayer on the blend membrane which demonstrated that the membrane was suitable for corneal endothelial cells to attach and grow. In addition, the membranes in vivo showed a good bioabsorption property. The mild symptoms of inflammation at sites of treatment could be resolved as the implant was absorbed by the host. The results of this study demonstrated that the hydroxypropyl chitosan-chondroitin sulfate-gelatin blend membrane can potentially be used as a carrier for corneal endothelial cell transplantation. [ABSTRACT FROM AUTHOR]

Marine bacterium Vibrio sp. F-6, utilizing agarose as a carbon source to produce agarases, was isolated from seawater samples taken from Qingdao, China. Two agarases (AG-a and AG-b) were purified to a homogeneity from the cultural supernatant of Vibrio sp. F-6 through ammonium sulfate precipitation, Q-Sepharose FF chromatography, and Sephacryl S-100 gel filtration. Molecular weights of agarases were estimated to be 54.0 kDa (AG-a) and 34.5 kDa (AG-b) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH values for AG-a and AG-b were about 7.0 and 9.0, respectively. AG-a was stable in the pH range of 4.0–9.0 and AG-b was stable in the pH range of 4.0–10.0. The optimum temperatures of AG-a and AG-b were 40 and 55 °C, respectively. AG-a was stable at temperature below 50 °C. AG-b was stable at temperature below 60 °C. Zn2+, Mg2+ or Ca2+ increased AG-a activity, while Mn2+, Cu2+ or Ca2+ increased AG-b activity. However, Ag+, Hg2+, Fe3+, EDTA and SDS inhibited AG-a and AG-b activities. The main hydrolysates of agarose by AG-a were neoagarotetraose and neoagarohexaose. The main hydrolysates of agarose by AG-b were neoagarooctaose and neoagarohexaose. When the mixture of AG-a and AG-b were used, agarose was mainly degraded into neoagarobiose. [ABSTRACT FROM AUTHOR]

Abstract  Aqueous purified extract (PE) was isolated from the crude extract (CE) of the marine mollusk, Ruditapes philippinarum. Two water-soluble polysaccharides, PEF1 and PEF2, were purified from PE. The chemical structures were determined using FTIR, GC, HPLC and 13C NMR. The results indicated that PEF1 and PEF2 were homoglucan–protein complexes with a protein content of 26.0 and 8.2%, and their average molecular weights were about 2.0 × 106 and 5.0 × 103, respectively. The glucan moiety of PEF1 was mainly a (1 → 6)-branched (1 → 4)-α-d-glucan, while that of PEF2 contained (1 → 4)-α-d-glucan and (1 → 6)-β-d-glucan. PE fractions contained large quantities of glutamic acid and aspartic acid, but no cysteine. The antitumor activities were tested both in vitro and in vivo. PE showed significantly the highest tumoricidal activity against human hepatoma SMMC-7721 cells, and PEF1 had better cytotoxicity than PEF2. There was no observed cytotoxicity in human hepatocyte HL-7702 cells within the experimental concentration range for all PE fractions. PE showed antitumor activity against solid tumor Sarcoma 180 in a dose-dependent manner. It also demonstrated stimulating effect on murine lymphocyte proliferation induced by concanavalin A. The results demonstrated that the presence of bound protein, compositional glucan and moderate molecular mass would be helpful to the enhancement of antitumor activities. This study suggested that the polysaccharides isolated from the marine mollusk had a potential application as natural antitumor and immunomodulator agents. [ABSTRACT FROM AUTHOR]

A novel potent protease, Urechis unicinctus fibrinolytic enzyme (UFE), wasfirst discovered by our laboratory. In this study, we further investigated theenzymatic properties and dynamic parameters of UFE. As a low molecularweight protein, UFE appeared to be very stable to heat and pH. When thetemperature was <50°C, the remnant enzyme activity remained almostunchanged, but when the temperature was raised to 60°C the remnantenzyme activity began to decrease rapidly. UFE was quite stable in a pHrange of 3.0-12.0, especially at slightly alkaline pH values. Mn2+, Cu2+, andFe2+ ions were activators of UFE, whereas Fe3+ and Ag+ ions were inhibitors.Fe2+ ion along with Fe3+ ion might regulate UFE activity in vivo. The optimumpH and temperature of UFE were about 8.0 and 50°C, respectively. Whenusing casein as substrate and a substrate concentration <0.1% casein (w/v),the reaction velocity was increased with substrate concentration. Alsowhen using casein as substrate, the determined Km and Vmax of UFE were0.5298 mg/mL and 3.0845 mol of L-tyrosine equivalent, respectively. Oursystematic research results are significant when UFE is applied for medicaland industrial purposes. [ABSTRACT FROM AUTHOR]

Two extracellular chitosanases (ChiX and ChiN) were extracted from Microbacterium sp. OU01 with Mr values of 81 kDa (ChiX) and 30 kDa (ChiN). ChiN was optimally active at pH 6.2 and 50°C and ChiX at pH 6.6 and 60°C (assayed over 15 min). Both the activities increased with the degree of deacetylation (DDA) of chitosan. ChiN hydrolyzed oligomers of glucosamine (GlcN) larger than chitopentaose, and chitosan with 62–100% DDA; but ChiX acted on chitosan and released GlcN. Hydrolysis of chitosan with 99% DDA by ChiN released chitobiose, chitotriose and chitotetraose as the major products. [ABSTRACT FROM AUTHOR]

Abstract: The protective effects of chitosan oligosaccharide (COS), d-glucosamine (GlcNH2) and N-acetyl-d-glucosamine (GlcNAc) on carbon tetrachloride (CCl4)-induced hepatotoxicity and the possible mechanisms that involved were investigated in male ICR mice. CCl4 (20mg/kg body weight, i.p.) administration induced marked increase in serum AST and ALT activities, primed liver lipid peroxidation, depleted sulfhydryl content, impaired total antioxidant capabilities and induced genotoxicity 24h after administration. Pretreatment with COS, GlcNH2, and GlcNAc (1.5g/kg body weight, i.g.) for 12 consecutive days prior to CCl4 challenge significantly induced metallothionein (MT) expression. Thus, the antioxidant defensive system in the body was strengthened to counteract the oxidative damage induced by the succedent CCl4 administration. Serum AST and ALT activities were effectively decreased. Hepatic malondialdehyde formation was inhibited and sulfhydryl contents, total antioxidant capabilities were markedly restored. Genotoxicity as reflected by DNA fragmentation, however, was not mitigated by pretreatment with COS, GlcNH2, and GlcNAc. Histophathologic results of liver also confirmed their hepato-protective effects. Pretreatment with COS, GlcNH2, and GlcNAc also could significantly decrease serum creatinine and uric acid levels and inhibit lipid peroxidation in kidney homogenate. Our results suggest that pretreatment with COS, GlcNH2, and GlcNAc can efficiently protect mice against CCl4-induced toxicity. [Copyright &y& Elsevier]

On the basis of previous achievements in Porphyra seedling production using enzymatically isolated thallus cells, we have investigated the influences of water content of thallus before freezing, storing temperature and enzymes on the viability of isolated cells. We have also tried outdoor cultivation of seedlings produced enzymatically in different seasons. It has been found that survival rate of isolated cells of thallus stored for two months can reach 90% if water content is 30% before freezing and storing temperature is constant at -20 °C. The 80% cell survival rate can be reached after two years of storage under this condition. The fluctuation of storing temperature causes drastic decrease of cell survival rate. 84% of the cells have survived digestion of sea snail enzyme I, which is the highest among five enzymes used. Outdoor cultivation of seedlings produced on the first ten days of January can reach lengths of more than 20 cm upon harvesting in the middle of May. In addition, seedlings produced in spring can be stored frozen and cultivated in autumn. The harvesting date will advance 15 days in comparison with the conventional seedling producing approach. This promises multiple rounds of cultivation of Porphyra within a year. % [ABSTRACT FROM AUTHOR]

Hydrogels have excellent swelling properties and have been widely applied in tissue engineering because of their similarity to the extracellular matrix (ECM). Sodium alginate (SA) and carboxymethyl chitosan (CMCS) were prepared into hydrogel microspheres with Ca 2+ crosslinking in our study. The morphology, inner structure, mechanical properties, water content, swelling rate and BMP-2 loading and releasing properties were characterized. Our results showed that the composite SA /CMCS hydrogel microspheres were translucent and spherical in shape with uniform particle size. The incorporation of CMCS further increased the diameters of the microspheres, internal pore structure, water content, and mechanical properties of the SA/CMCS hydrogel microspheres. At the same SA concentration, with the increase of CMSC concentration, the diameter of microspheres could be increased by about 0.4 mm, the water content can be increased about 1%-2%. As for the mechanical properties, the compressive strength can be increased by 0.04-0.1 MPa, and the modulus of elasticity can be increased by 0.1-0.15 MPa. BMP-2 was chosen as a model agent and it could be loaded into SA/CMCS microspheres, and the incorporation of CMCS increased BMP-2 loading. The encapsulated BMP-2 was sustainably released in vitro . The leaching solutions of the SA/CMCS hydrogel microspheres exhibited good cytocompatibility and could increase ALP activity, ALP expression, and biomineralization on MC3T3-E1 cells. After 7 d of co-culture, ALP activities in S2.5C2 and S2.5C3 groups was increased by 50% and 45% compared with that of the control group. When embedded in the SA/CMCS microspheres, the MC3T3-E1 cells were evenly distributed inside the hydrogel microspheres and remained viable. Transcriptomic studies showed that incorporation of CMCS induced upregulation of 1141 differentially expressed genes (DEGs) and downregulation of 1614 DEGs compared with SA microspheres. The most significantly enriched pathways were the Wnt and MAPK signaling pathways induced by the incorporation of CMCS and BMP-2. In conclusion, our results indicated that the physiochemical characteristics of the SA hydrogel microspheres could be greatly modulated by CMCS to better mimic the ECM microenvironment and induce osteo-inductive activities of MC3T3-E1 cells., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

This study aimed to synthesize bioactive glass (BG) and phosphorylated chitosan (PCS), and fabricate a BG/PCS composite scaffold. The physical properties (mechanical strength, swelling degree, and degradation rate) of the BG/PCS scaffold were tested. The in vitro mineralization properties of composite scaffolds in simulated body fluid were investigated. MC3T3-E1 cell responses with the BG/PCS scaffold were investigated using live/dead cell staining, actin staining, alkaline phosphatase (ALP) activity, and Alizarin red staining. Our results showed that the scaffold had an inner porous structure, good swelling properties, and good degradation rate. After immersion in SBF, the scaffolds demonstrated high properties in inducing mineralization. Leaching solutions of the composite scaffolds exhibited good cytocompatibility. MC3T3-E1 cells adhered, spread, and proliferated on the scaffold. The BG/PCS composite scaffold showed osteo-inductive activity by increasing ALP activity and calcium deposition. Our results indicated that the BG/PCS scaffold had potential applications as a bone-defect repair biomaterial., (© 2024 IOP Publishing Ltd.)