Search

Recent studies have suggested that exosomes exert similar therapeutic effects to those of mesenchymal stem cells (MSCs) in regenerative medicine and MSCs-derived exosomes exhibit therapeutic effects on steroid-induced osteonecrosis of the femoral head (ONFH). Furthermore, reparative functions of exosomes from MSCs are enhanced by hypoxia treatment of the cells. However, there are no related reports about whether exosomes derived from hypoxia-preconditioned MSCs could show better therapeutic effects on steroid-induced ONFH. In vitro, we investigated the effects of hypoxia precondition on exosomes derived from bone marrow mesenchymal stem cells (BMMSCs) from rats and the proangiogenic ability of exosomes derived from hypoxia-preconditioned BMMSCs. In vivo, we investigated the role of exosomes from hypoxia-preconditioned BMMSCs on angiogenesis and protecting osteonecrosis in a rat ONFH model. We found that the potential of the proangiogenic ability of exosomes derived from hypoxia-preconditioned BMMSCs was higher than exosomes derived from BMMSCs cultured under normoxia. Exosomes derived from hypoxia-preconditioned BMMSCs significantly promoted proliferation, migration, vascular endothelial growth factor (VEGF) expression, and tube formation of human umbilical vein endothelial cells (HUVECs) compared with exosomes derived from BMMSCs cultured under normoxia. Administration of exosomes derived from hypoxia-preconditioned BMMSCs significantly prevented bone loss and increased vessel volume in the femoral head compared with exosomes derived from BMMSCs cultured under normoxia. Taken together, our data suggest that exosomes derived from hypoxia-preconditioned BMMSCs exert better therapeutic effects on steroid-induced ONFH by promoting angiogenesis and preventing bone loss. [ABSTRACT FROM AUTHOR]

Stimulated emission depletion (STED) nanoscopy is a promising fluorescence microscopy to detect unresolvable structures at the nanoscale level and then achieve a superior imaging resolution in materials science and biological research. However, in addition to the optimization of the microscope, luminescent materials in STED nanoscopy are also of great significance to obtain imaging, visualization and even long-term tracking at an ultra-high resolution (less than 100 nm), but this is seldom summarized. Based on this consideration, recent progress on STED fluorophores for super-resolution imaging is outlined here, including inorganic fluorophores, fluorescent proteins, organic luminescent materials, aggregation-induced emission (AIE) luminogens, and fluorescent nanoparticles. Characteristics of these aforementioned STED fluorophores are also included and compared to provide a deep understanding of the relationship between the properties in luminescent materials and their performance in STED imaging. According to the results on such luminescent materials, it is anticipated that guidelines to select proper probes and even develop new materials for super-resolution imaging via STED nanoscopy will be provided here, finally promoting the development of super-resolution imaging in both materials science and biological research. [ABSTRACT FROM AUTHOR]

Objective. Methane saline (MS) can be used to treat many diseases via its anti-inflammatory, antiapoptotic, and antioxidative activities. However, to date, there is no published evidence as to whether MS has any effect on traumatic brain injury (TBI). The Wnt signalling pathway regulates cell proliferation, differentiation, migration, and apoptosis; however, whether the Wnt signalling pathway regulates any effect of MS on TBI is unknown. This study was designed to explore the role of MS in the treatment of TBI and whether the Wnt pathway is involved. Methods. Sprague-Dawley rats were randomly divided into five groups: sham, TBI, TBI+10 ml/kg MS, TBI+20 ml/kg MS, and TBI+30 ml/kg MS. After induction of TBI, MS was injected intraperitoneally once daily for seven consecutive days. Neurological function was evaluated by the Neurological Severity Score (NSS) at 1, 7, and 14 days after TBI. Haematoxylin-eosin (HE) staining, inflammatory factors, neuron-specific enolase (NSE) staining, oxidative stress, and cell apoptosis were measured and compared 14 d after TBI to identify the optimal dose of MS and to investigate the effect of MS on TBI. In the second experiment, Sprague-Dawley rats were randomly divided into four groups: sham, TBI, TBI+20 ml/kg MS, and TBI+20 ml/kg MS+Dickkopf-1 (DKK-1, a specific inhibitor of the Wnt pathway). NSE, caspase-3, superoxide dismutase (SOD), Wnt3a, and β-catenin were detected by real-time PCR and Western blotting. The results from each group were compared 14 d after TBI to determine the regulatory role of the Wnt pathway. Results. Methane saline significantly inhibited inflammation, oxidative stress, and cell apoptosis, thus protecting neurons within 14 days of TBI. The best treatment effect against TBI was obtained with 20 ml/kg MS. When the Wnt pathway was inhibited, the treatment effect of MS was impaired. Conclusion. Methane saline ameliorates TBI through its anti-inflammatory, antiapoptotic, and antioxidative effects via activation of the Wnt signalling pathway, which plays a part but is not the only mechanism underlying the effects of MS. Thus, MS may be a novel strategy for treating TBI. [ABSTRACT FROM AUTHOR]

Small extracellular vesicles (sEVs) derived from bone marrow mesenchymal stem cells (BMMSCs) from individuals with steroid-induced osteonecrosis of the femoral head (ONFH) have not been studied. The objective of the present study was to compare the proosteogenic and proangiogenic effects of sEVs derived from BMMSCs from rats with steroid-induced ONFH (oBMMSCs-sEVs) and sEVs derived from BMMSCs from normal rats (nBMMSCs-sEVs). BMMSCs were isolated from steroid-induced ONFH rats and healthy rats. sEVs were isolated and characterized by Western blotting analysis of exosomal surface biomarkers and by transmission electron microscopy. The impacts of nBMMSCs-sEVs and oBMMSCs-sEVs on the proliferation and osteogenic differentiation of BMMSCs were determined via cell proliferation assay, alizarin red staining, and alkaline phosphatase activity assay. Enzyme-linked immunosorbent assay and tube formation assay were conducted to investigate the effect of nBMMSCs-sEVs and oBMMSCs-sEVs on the angiogenic potential of human umbilical vein endothelial cells (HUVECs). The expression of relevant genes was detected by quantitative real-time polymerase chain reaction analysis, and the expression of β-catenin was detected by immunofluorescence. Both nBMMSCs-sEVs and oBMMSCs-sEVs promoted proliferation, osteogenic differentiation, and β-catenin expression of BMMSCs and enhanced angiogenesis of HUVECs. However, compared with nBMMSCs-sEVs, oBMMSCs-sEVs exhibited attenuated effects. Our findings indicated that the proosteogenic and proangiogenic effects of sEVs were partially attenuated in steroid-induced ONFH. Therefore, this study might offer guidance for the selection of source cells for sEV therapy in the future. [ABSTRACT FROM AUTHOR]

The therapeutic effect of stem cell transplantation in traumatic spinal cord injury (SCI) has been extensively studied these days, and evidence has shown that stem cell-derived exosomes and exosome-shuttled miRNA (e.g. miR-21) contribute to the protective effects of stem cell transplantation against SCI. It has been reported that obesity, a prevalent metabolic disorder, reshapes stem cells and their extracellular vesicles. However, the effects of exosomes derived from obese rat stem cells on SCI and its underlying mechanism remain unknown. Here, we examined the effects of exosomes derived from obese rat mesenchymal stem cells (MSCs) on SCI, and tested the role of miR-21 in their effects. We found that exosomes derived from obese rat MSCs showed decreased miR-21 levels and did not exert protective effects against SCI. Overexpression of miR-21 in obese rat MSCs restored the protective effects of exosomes purified from obese rat MSCs against SCI. In addition, obese rat MSCs showed insulin resistance, and MSC insulin resistance decreased miR-21 levels in its secreted exosomes. These results suggested that miR-21 deficiency in obese rat MSCs contributes to the impaired protective effects of obese rat MSCs-derived exosomes against SCI, and further reinforced the notion that miR-21 is a potential molecule for treatment of SCI. • Obe-exo showed decreased miR-21 and little protective effect against SCI. • Overexpression of miR-21 restored the protective effect of Obe-exo against SCI. • Insulin resistance decreased miR-21 in MSC-secreted exosomes. • miR-21 deficiency contributes to the impaired protective effect of Obe-exo. [ABSTRACT FROM AUTHOR]

Introduction: Spinal cord impact is a mature method for building models of spinal cord injury (SCI). However, a common problem is that the degree of elicited paralysis may not be identical even though animals receive the same impact. We hypothesize that this difference may be caused by the difference in the secondary injury mechanism of SCI and there might be an impact dosage named "median paralyzing dose (PD50)", similar as the "median lethal dose (LD50)" in pharmacology. In addition, since SCI is a result of multiple mechanisms, we hypothesize that it is more suitable to employ multiple regression analysis to analyze the related factors for complete paraplegia. So the present study aimed to calculate the existence of PD50 and analyze the related factors of SCI-induced complete paralysis using logistic regression under the PD50 which represents identical primary injury.Material and Methods: Rat models of SCI were built using the weight-drop method under PD50. PD50 was calculated by Karber's method. Rats were allocated into two groups according to whether they developed complete or incomplete paralysis 2 weeks after injury. Cavity and spared tissues in the two groups were compared. Neuronal preservation, microglia/macrophage reaction, T-lymphocyte infiltration, astrocyte activation and neuronal apoptotic were compared by immunohistochemistry. The logistic regression model was constructed and significant related factors of complete paralysis were selected.Results: Of the two groups, the cavity in the injured spinal cord of the complete-paralysis rats was significantly larger and the spared white matter volume (SWMV%) was obviously smaller. Whereas, the spared grey matter volume was not different between groups. Macrophage reaction, T-lymphocyte infiltration and neuronal apoptosis were significantly more severe in the complete-paralysis rats. Astrocyte activation and neuronal preservation showed no difference between groups. Logistic regression analysis showed that cavity volume, SWMV%, microglia/macrophage reaction and neuronal apoptosis were significantly correlated with SCI-induced complete paralysis.Conclusion: As a non-mainstream method, it is feasible to analyze the secondary factors of SCI-induced complete paralysis using multiple regression analysis in the condition of identical primary injury (PD50). SWMV% and microglia/macrophage reaction are important factors that contribute to complete paralysis at the early phase of severe SCI. [ABSTRACT FROM AUTHOR]

Spinal cord injury (SCI) causes tissue destruction and neuronal apoptosis, which impede neural function recovery. Therefore, promoting neuronal regeneration and neural pathway reconstruction is crucial. In this study, a novel and facile decellularized extracellular matrix (dECM) scaffold seeded with adipose-derived stem cells (ADSCs) (dECM scaffolds/ADSCs) was reported. The dECM scaffold maintained the original three-dimensional network structure of spinal cord tissue and contained various small pores. In vitro studies demonstrated that dECM scaffolds exhibited excellent biocompatibility, facilitated efficient adhesion and proliferation of ADSCs, and promoted the secretion of neurotrophin-3 and neuronal differentiation in the microenvironment after SCI. In vivo studies further showed that dECM scaffolds/ADSCs could alleviate inflammatory and apoptotic reactions, providing a favorable microenvironment for promoting endogenous nerve regeneration rather than glial scars formation, ultimately achieving recovery of hind limb function in rats. Notably, ICG-001 effectively reversed the therapeutic effect of dECM scaffolds/ADSCs, proving that dECM scaffolds/ADSCs promoted functional recovery after SCI by regulating the Wnt/ β -catenin signaling pathway. Overall, dECM scaffolds/ADSCs can simulate the physiological characteristics of the spinal cord and exert neurorestorative potential, providing a new therapeutic strategy for SCI., (© 2023 IOP Publishing Ltd.)

The completed skeletal muscle regeneration resulted from severe injury and muscle-related disease is still a challenge. Here, we developed an injectable muscle-adhesive antioxidant conductive bioactive photothermo-responsive nanomatrix for regulating the myogenic differentiation and promoting the skeletal muscle regeneration in vivo . The multifunctional nanomatrix was composed of polypyrrole@polydopamine (PPy@PDA, 342 ± 5.6 nm) nanoparticles-crosslinked Pluronic F-127 (F127)-polycitrate matrix (FPCP). The FPCP nanomatrix demonstrated inherent multifunctional properties including excellent photothermo-responsive and shear-thinning behavior, muscle-adhesive feature, injectable ability, electronic conductivity (0.48 ± 0.03 S/m) and antioxidant activity and photothermal function. The FPCP nanomatrix displayed better photothermal performance with near-infrared irradiation, which could provide the photo-controlled release of protein (91% ± 2.6% of BSA was released after irradiated 3 times). Additionally, FPCP nanomatrix could significantly enhance the cell proliferation and myogenic differentiation of mouse myoblast cells (C2C12) by promoting the expressions of myogenic genes (MyoD and MyoG) and myosin heavy chain (MHC) protein with negligible cytotoxicity. Based on the multifunctional properties, FPCP nanomatrix efficiently promoted the full-thickness skeletal muscle repair and regeneration in vivo , through stimulating the angiogenesis and myotube formation. This study firstly indicated the vital role of multifunctional PPy@PDA nanoparticles in regulating myogenic differentiation and skeletal muscle regeneration. This work also suggests that rational design of bioactive matrix with multifunctional feature would greatly enhance the development of regenerative medicine., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2020 The Authors. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.)

Rolipram, a phosphodiesterase-4 inhibitor, can activate the cyclic adenosine monophosphate (cAMP)/cAMP-responsive element binding protein (CREB) pathway to facilitate functional recovery following ischemic stroke. However, to date, the effects of rolipram on angiogenesis and cerebral ischemia-induced neuronal apoptosis are yet to be fully elucidated. In this study, the aim was to reveal the effect of rolipram on the angiogenesis and neuronal apoptosis following brain cerebral ischemia. Rat models of ischemic stroke were established following transient middle cerebral artery occlusion and rolipram was administered for three, seven and 14 days. The results were examined using behavioral tests, triphenyl tetrazolium chloride staining, immunostaining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) to evaluate the effects of rolipram therapy on functional outcome, angiogenesis and apoptosis. Western blot analysis was used to show the phosphorylated- (p-)CREB protein level in the ischemic hemisphere. The rolipram treatment group exhibited a marked reduction in infarct size and modified neurological severity score compared with the vehicle group, and rolipram treatment significantly promoted the microvessel density in the ischemic boundary region and increased p-CREB protein levels in the ischemic hemisphere. Furthermore, a significant reduction in the number of TUNEL-positive cells was observed in the rolipram group compared with the vehicle group. These findings suggest that rolipram has the ability to attenuate cerebral ischemic injury, stimulate angiogenesis and reduce neuronal apoptosis though the cAMP/CREB pathway.

Tissue engineering is a promising method that may be used to treat spinal cord injury (SCI). The underlying repair mechanism of tissue engineering involves the stable secretion of neurotrophins from seed cells, which eventually differentiate into neurons; therefore, the selection of appropriate seed cells, which stably secrete neurotrophins that easily differentiate into neurons requires investigation. Adipose‑derived stem cells (ADSCs), which are adult SCs, are advantageous due to convenience sampling and easy expansion; therefore, ADSCs are currently the most popular type of seed cell. Brain‑derived neurotrophic factor (BDNF) and neurotrophin‑3 (NT‑3) possess superior properties, when compared with other neurotrophic factors, in the maintenance of neuronal survival and promotion of SC differentiation into neurons. The present study used two lentiviruses, which specifically express BDNF and NT‑3 [Lenti‑BDNF‑green fluorescent protein (GFP), Lenti‑NT‑3‑red fluorescent protein (RFP)], to transfect third‑generation ADSCs. Three types of seed cell were obtained: i) Seed cells overexpressing BDNF (ADSC/Lenti‑BDNF‑GFP); ii) seed cells overexpressing NT‑3 (ADSC/Lenti‑NT‑3‑RFP); and iii) seed cells overexpressing BDNF and NT‑3 (ADSC/Lenti‑BDNF‑GFP and NT‑3‑RFP). The transfected cells were then induced to differentiate into neurons and were divided into a further four groups: i) The BDNF and NT‑3 co‑overexpression group; ii) the BDNF overexpression group; iii) the NT‑3 overexpression group; and iv) the control group, which consisted of untransfected ADSCs. The results of the present study demonstrate that BDNF and NT‑3 expression was higher 10 days after induction, as detected by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) and western blotting. Neuron‑specific enolase is a neuronal marker, the expression of which was highest in the BDNF and NT‑3 co‑overexpression group, followed by the BDNF overexpression group and then by the NT‑3 overexpression group. The lowest expression levels of NSE were detected in the control group, as determined by RT‑qPCR, western blotting and immunofluorescent staining. These results indicate that BDNF and NT‑3 exert a synergistic effect, which may promote the neuronal differentiation of ADSCs. The present study provides a solid theoretical foundation for future experiments regarding the use of tissue engineering technology for the treatment of SCI.

The specific pathogenesis of steroid‑induced osteonecrosis (ON) is yet to be elucidated and until recently effective prophylactic therapies have not been available. The local renin‑angiotensin system (RAS) exists in the bone and has an important role in local bone regulation. However, to the best of our knowledge, the interrelation between local bone RAS and steroid‑induced ON is yet to be investigated. In the present study, 45 rabbits were injected with a single intramuscular dose of 20 mg/kg methylprednisolone acetate (MPA) and were sacrificed 1 (group A), 2 (group B) and 3 (group C) weeks subsequent to MPA administration (n=15 per group). Ten rabbits were used as a control group (group N). The presence or absence of ON in the bilateral femoral heads was examined histopathologically. The mRNA and protein expression of components of the RAS, including angiotensin II (Ang II), angiotensin converting enzyme (ACE) and Ang II type 1 (AT1) and Ang II type 2 (AT2) receptors, were detected in the bone. Significant changes in Ang II, ACE, and AT1 and AT2 receptor expression were observed in the bone of the rabbits in the different groups. Moreover, the expression of Ang II and ACE was highest one week subsequent to administration of the glucocorticoid methylprednisolone and the expression of the AT1 and AT2 receptors was highest two weeks following methylprednisolone administration. ON occurs most significantly at three weeks following the administration of MPA in this animal model, thus the changes in Ang II, ACE and AT1 and AT2 receptor expression preceded this. The present study found that ON was strongly associated with the activation of the local bone RAS in rabbits.

Spinal cord injury (SCI) may lead to a devastating and permanent loss of neurological function, which may place a great economic burden on the family of the patient and society. Methods for reducing the death of neuronal cells, inhibiting immune and inflammatory reactions, and promoting the growth of axons in order to build up synapses with the target cells are the focus of current research. Target cells are located in the damaged spinal cord which create a connect with the scaffold. As tissue engineering technology is developed for use in a variety of different areas, particularly the biomedical field, a clear understanding of the mechanisms of tissue engineering is important. This review establishes how this technology may be used in basic experiments with regard to SCI and considers its potential future clinical use.

The use of tissue engineering technology in the repair of spinal cord injury (SCI) is a topic of current interest. The success of the repair of the SCI is directly affected by the selection of suitable seed cells and scaffold materials with an acceptable biocompatibility. In this study, adipose tissue-derived stem cells (ADSCs) were incorporated into a silk fibroin-chitosan scaffold (SFCS), which was constructed using a freeze-drying method, in order to assess the biocompatibility of the ADSCs and the SFCS and to provide a foundation for the use of tissue engineering technology in the repair of SCI. Following the seeding of the cells onto the scaffold, the adhesion characteristics of the ADSCs and the SFCS were assessed. A significant difference was observed between the experimental group (a composite of the ADSCs with the SFCS) and the control group (ADSCs without the scaffold) following a culture period of 6 h (P<0.05). The differences in the results at the following time-points were statistically insignificant (P>0.05). The use of an MTT assay to assess the proliferation of the cells on the scaffold revealed that there were significant differences between the experimental and control groups following culture periods of 2 and 4 days (P<0.05). However, the results at the subsequent time-points were not statistically significantly different (P>0.05). Scanning electron microscopy (SEM), using hematoxylin and eosin (H&E) staining, was used to observe the cellular morphology following seeding, and this revealed that the cells displayed the desired morphology. The results indicate that ADSCs have a good biocompatibility with a SFCS and thus provide a foundation for further studies using tissue engineering methods for the repair of SCI.