Search

Introduction: Gonadotropin-releasing hormone (GnRH) is widely used in the timed artificial insemination protocol for sheep. However, there remains a debate regarding its impact on pregnancy rates during artificial insemination. This study aims to evaluate the effect of GnRH on the pregnancy rates in Huyang ewes, analyze the pre-implantation metabolite changes caused by GnRH using metabolomics, and elucidate the mechanism effect on pregnancy rates. Methods: All ewes were administered a vaginal progesterone sponge containing 45  mg of flurogestone acetate for 12  days and received 330  units of equine chorionic gonadotropin (eCG) intramuscularly after sponge removal. The experimental group (n  =  69) received an intramuscular treatment of 17  μg GnRH agonist triptorelin 48  h after sponge removal on Day 0, while the control group (n  =  41) received 1  mL of sterile saline solution. All ewes underwent a single vaginal insemination 58  h after the withdrawal of the progesterone sponge. The difference in pregnancy rates between the two groups was calculated. Metabolomic analysis was performed on plasma samples collected on Day 7 after the treatment of GnRH agonist. Results: Gonadotropin-releasing hormone (GnRH) treatment significantly reduced the pregnancy rate in the experimental group compared with the control group (72.2 vs. 82.9%, p  <  0.05). Metabolomic analysis indicated that GnRH treatment affected metabolites involved in collagen synthesis and prostaglandin synthesis in the endometrial tissue, which includes a marked decrease in hydroxyproline amino acid content and a significant increase in corticosterone and prostaglandin D2 lipids and unsaturated fatty acids. Conclusion: In summary, the injection of GnRH agonist Triptorelin 48  h after progesterone sponges removal reduces the pregnancy rate of Huyang ewe following artificial insemination. It also affects the metabolite levels related to endometrial collagen and prostaglandin synthesis, harming embryo implantation. [ABSTRACT FROM AUTHOR]

Stroke is a leading cause of death and disability in the world. Astrocytes are special glial cells within the central nervous system and play important roles in mediating neuroprotection and repair processes during stroke. Extracellular vesicles (EVs) are lipid bilayer particles released from cells that facilitate intercellular communication in stroke by delivering proteins, lipids, and RNA to target cells. Recently, accumulating evidence suggested that astrocyte-derived EVs (ADEVs) are actively involved in mediating numerous biological processes including neuroprotection and neurorepair in stroke and they are realized as an excellent therapeutic approach for treating stroke. In this review we systematically summarize the up-to-date research on ADEVs in stroke, and prospects for its potential as a novel therapeutic target for stroke. We also provide an overview of the effects and functions of ADEVs on stroke recovery, which may lead to developing clinically relevant therapies for stroke. [ABSTRACT FROM AUTHOR]

Introduction: Superovulation is a critical step in assisted reproductive technology, but the use of human chorionic gonadotropin (hCG) as a trigger for superovulation can result in ovarian hyperstimulation. Thus, the use of Gonadotropin-releasing hormone agonist (GnRHa) trigger has been increasingly adopted, although it has been associated with a higher rate of pregnancy failure compared to natural cycles. This study aimed to investigate the effect of GnRHa trigger on embryo implantation in a mouse model. Methods: Mice in the superovulation (PG) group were administered 7.5 IU of PMSG, followed by the injection of 3.5 mg of GnRHa (Leuprorelin) 48 h later, whilemice in the control group (CTR) mated naturally. We compared the number of oocytes, blastocysts, and corpus luteum between the two groups and the implantation sites after the transfer of natural blastocysts. Ovaries, uterus, and serum 2 and 4 days after mating were collected for qRT-PCR, transcriptome sequencing, and hormone assays. Results: The PG group had more oocytes, blastocysts, and corpus luteum after superovulation than the CTR group. However, the mRNA expression of leukemia inhibitory factor (Lif) and the number of implantation sites were reduced in the PG group. The ELISA assay revealed that superovulation increased ovarian estrogen secretion. The transcriptome analysis showed that superphysiological estrogen led to a response of the uterus to a high estrogen signal, resulting in abnormal endometrium and extracellular matrix remodeling and up-regulation of ion transport and inflammation-related genes. Conclusion: Our findings suggest that a combination of PMSG and GnRHa trigger impaired embryo implantation in mice, as the excessive uterine response to superphysiological estrogen levels can lead to the change of gene expression related to endometrial remodeling, abnormal expression of uterine ion transport genes and excessive immune-related genes. [ABSTRACT FROM AUTHOR]

Background: Chukrasia tabularisis, a well-known tropical tree native to southeastern China, has anti-inflammatory and antioxidant activities, and contains large amounts of limonoids and triterpenoids. Objective: The aim of this study was to investigate the potential anti-inflammatory activity of limonoids from C. tabularis on lipopolysaccharide (LPS)-mediated RAW264.7 cells. Methods and results: Using a bioassay-guided approach, the chemical fraction with high anti-inflammatory activity was found and its chemical constituents were investigated. Phytochemical studies on active extracts resulted in the separation of three novel phragmalin limonoids (1-3), together with two known limonoids (4-5) and 11 tirucallane triterpenes (6-16). The activity of these isolated compounds in the production of nitric oxide (NO) on LPS-reated macrophages was evaluated. Limonoid 2 indicated significant anti-inflammatory activities with IC50 value of 4.58 µM. Limonoid 2 notably inhibited the production of NO, interleukin- 6 and tumor necrosis factor-α on macrophage. Signal transduction and activation of STAT and NF-κB activators were effectively blocked by limonoid 2. Conclusions: These results indicate that limonoid 2 has an anti-inflammatory effect by the inhibiting JAK2/STAT3, iNOS/eNOS, and NF-κB signaling pathways and regulating inflammatory mediators. [ABSTRACT FROM AUTHOR]

In this study, the fully distributed adaptive iterative learning coordination control of the uncertain non-linear leader-follower multi-agent systems with input saturation is studied. Under the alignment initial condition and Lyapunov theory, a novel adaptive distributed control protocol with a fully saturated parameter learning law is designed. Despite the existence of input saturation, the global perfect consensus tracking can be realised over a finite time interval. Besides, the consensus tracking problem is extended to the formation control problem as well. Ultimately, the validity of theoretical analysis of this study is shown by two examples. [ABSTRACT FROM AUTHOR]

Background: Oxidized low-density lipoprotein (ox-LDL) can induce endothelial injury and plays a vital role in the procession and development of atherosclerosis. Little is known regarding whether Wnt/β-catenin pathway is involved in ox-LDL-induced endothelial injury or whether it further promotes atherosclerosis via increased oxidative stress. This study aimed to investigate the role of Wnt/β-catenin pathway in ox-LDL-induced vascular endothelial injury and determine whether pigment epithelium-derived factor (PEDF) could alleviate ox-LDL-induced endothelial injury by inhibiting Wnt/β-catenin pathway. Methods: Injury of human umbilical vein endothelial cells (HUVECs) was evaluated with an MTT assay, by monitoring lactate dehydrogenase (LDH) release and determining the apoptotic ratio. The expression of β-catenin (non-phosphorylated-β-catenin), disheveled-1 (Dvl-1) and Cyclin D1 was analyzed with western blotting and quantitative real-time PCR. Oxidative stress status was assessed by measuring the levels of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD) and nitric oxide (NO). Results: Exposure of HUVECs to ox-LDL led to a decrease in cell viability and an increase in LDH release and apoptosis with concomitant enhancement of oxidative stress, as assessed by increased ROS and MDA generation, as well as decreased SOD activity and NO levels. Similar to lithium chloride (LiCl, a Wnt/β-catenin pathway activator), ox-LDL up-regulated the expression of β-catenin, Dvl-1 and Cyclin D1, markers of Wnt/β-catenin pathway activation. However, ox-LDL-induced activation of Wnt/β-catenin pathway, as well as ox-LDL-induced cell injury and oxidative stress, were synergistically promoted by LiCl and mitigated by Dickkopf 1 (DKK-1), an inhibitor of Wnt/β-catenin pathway. Additionally, ox-LDL-induced HUVEC injury and apoptosis, oxidative stress and activation of Wnt/β-catenin pathway were suppressed by PEDF, while they were further strengthened by a small interfering RNA of PEDF. Conclusion: Wnt/β-catenin pathway may mediate ox-LDL-induced endothelial injury via oxidative stress, and PEDF ameliorates endothelial injury by suppressing Wnt/β-catenin pathway and subsequently reducing oxidative stress. [ABSTRACT FROM AUTHOR]

Background: Cigarette smoke (CS) exposure impaired plasma lipid profiles by modification of apolipoproteins. Hydrogen (H2) has been proved effective on reducing oxidative stress or improving HDL functionalities in animal models or metabolic syndrome volunteers. This study was undertaken to explore the effects of CS exposure on reverse cholesterol transport (RCT) and the antioxidative effects of H2 treatment against CS exposure in mice transgenic for human cholesteryl ester transfer protein (CETP). Methods: [3H]-cholesterol-laden macrophages were injected intraperitoneally into mice, and the samples of blood, bile, liver, and feces were collected for radioactivity determination to evaluate RCT. [3H]-cholesterol-laden macrophages were incubated with HDL isolated from different groups of mice, and the samples of cell medium supernatants were collected for evaluating the HDL functionality to elicit cholesterol efflux. Results: CS exposure significantly decreased plasma HDL cholesterol level (HDL-C) by 22 % and increased LDL cholesterol level (LDL-C) by 21 % compared with the control group (p < 0.05, p < 0.01), while H2 treatment significantly improved the CS-impaired levels of TC, LDL-C and HDL-C by 10, 27 and 31 %, respectively, compared with the CS group (p < 0.05, p < 0.01 and p < 0.05). Besides, CS exposure significantly decreased [3H] tracer concentrations in liver, bile and feces by 17, 35 and 48 %, respectively, compared with the control group (p < 0.05 for liver and feces), while H2 treatment significantly improved them by 21, 72 % and 89 %, respectively, compared with the CS group (all p < 0.05). Furthermore, CS exposure significantly decreased the HDL functionality to elicit cholesterol efflux by 26 % (p < 0.05), while H2 treatment also improved it by 32 % (p < 0.05). We did not find any significant alterations in protein expressions of RCT involved genes. Conclusions: These findings provided direct evidence supporting the notion that CS exposure in vivo impairs plasma lipid profiles, HDL functionalities and macrophage-to-feces RCT pathway in CETP transgenic mice, all of which can be minimized by treatment of H2-saturated saline. [ABSTRACT FROM AUTHOR]

Although high density lipoprotein (HDL) improves the functions of endothelial progenitor cells (EPCs), the effect of HDL ApoAI mimetic peptide reverse-D-4F (Rev-D4F) on EPC mobilization and repair of EPC dysfunctions remains to be studied. In this study, we investigated the effects of Rev-D4F on peripheral blood cell subpopulations in C57 mice treated with a high fat diet and the mechanism of Rev-D4F in improving the function of EPCs impaired by tumor necrosis factor-α (TNF-α). The high fat diet significantly decreased the number of EPCs, EPC migratory functions, and the percentage of lymphocytes in the white blood cells. However, it significantly increased the number of white blood cells, the percentage of monocytes in the white blood cells, and the level of vascular endothelial growth factor (VEGF) and TNF-α in the plasma. Rev-D4F clearly inhibited the effect of the high fat diet on the quantification of peripheral blood cell subpopulations and cytokine levels, and increased stromal cell derived factor 1α (SDF-1α) in the plasma. We provided in vitro evidence that TNF-α impaired EPC proliferation, migration, and tube formation through inactive AKT and eNOS, which was restored by Rev-D4F treatment. In contrast, both the PI3-kinase (PI3K) inhibitor (LY294002) and AKT inhibitor (perifosine) obviously inhibited the restoration of Rev-4F on EPCs impaired by TNF-α. Our results suggested that Rev-D4F increases the quantity of endothelial progenitor cells through increasing the SDF-1α levels and decreasing the TNF-α level of peripheral blood in high fat diet-induced C57BL/6J mice, and restores TNF-α induced dysfunctions of EPCs partly through stimulating the PI3K/AKT signal pathway. [ABSTRACT FROM AUTHOR]

The study aimed to investigate the effect of niacin on vascular inflammatory lesions in vivo and in vitro as well as its lipid-regulating mechanism. In vivo study revealed that niacin downregulated the levels of inflammatory factors (IL-6 and TNF-κ) in plasma, suppressed protein expression of CD68 and NF-κB p65 in arterial wall, and attenuated oxidative stress in guinea pigs that have been fed high fat diet. In vitro study further confirmed that niacin decreased the secretion of IL-6 and TNF-α and inhibited NF-κB p65 and notch1 protein expression in oxLDL-stimulated HUVECs and THP-1 macrophages. Moreover, niacin attenuated oxLDLinduced apoptosis of HUVECs as well. In addition, niacin significantly lessened lipid deposition in arterial wall, increased HDLC and apoA levels and decreased TG and non-HDL-C levels in plasma, and upregulated the mRNA amount of cholesterol 7α- hydroxylase A1 in liver of guinea pigs.These data suggest for the first time that niacin inhibits vascular inflammation in vivo and in vitro via downregulatingNF-κB signaling pathway. Furthermore, niacin alsomodulates plasma lipid by upregulating the expression of factors involved in the process of reverse cholesterol transport. [ABSTRACT FROM AUTHOR]

In this work, we report the studies of drug metabolism by xanthine oxidase (XOD) with electrochemical techniques. Firstly, a pair of stable, well-defined and quasi-reversible oxidation/reduction peaks is obtained with the formal potential at -413.1 mV (vs. SCE) after embedding XOD in salmon sperm DNA membrane on the surface of pyrolytic graphite electrode. Then, a new steady peak can be observed at -730 mV (vs. SCE) upon the addition of 6-mercaptopurine (6-MP) to the electrochemical system, indicating the metabolism of 6-MP by XOD. Furthermore, the chronoamperometric response shows that the current of the catalytic peak located at -730 mV increases with addition of 6-MP in a concentration-dependent manner, and the increase of the chronoamperometric current can be inhibited by an XOD inhibitor, quercetin. Therefore, our results prove that XOD/DNA modified electrode can be efficiently used to study the metabolism of 6-MP, which may provide a convenient approach for in vitro studies on enzyme-catalyzed drug metabolism. [ABSTRACT FROM AUTHOR]

Endothelial progenitor cells (EPCs) derived from bone marrow are known to be heterogeneous. In this study, we tried to find favorable conditions that induce the differentiation of mononuclear cells (MNCs) from bone marrow into EPCs. The differentiation capacity of MNCs from rat bone marrow was investigated in different conditions, such as different media, different induction times and different culture surfaces. The cell morphology and endothelial biomarkers associated with differentiated MNCs were studied. Our results indicated that MNCs cultured in EGM-2MV (Endothelial cell basal medium-2, plus SingleQuots of growth supplements) developed a bursiform shape, a late EPC-like morphology, while MNCs cultured in complete medium (CM, M199 with 10% FBS, 20 ng/mL VEGF and 10 ng/mL bFGF) showed a spindle shape, an early EPC-like morphology. Cells of both morphologies were able to incorporate DiI-ac-LDL and bind lectin in vitro. MNCs cultured in EGM-2MV exhibited a higher proliferation rate and higher eNOS expression than MNCs cultured in CM. MNCs cultured in EGM-2MV had the ability to form tubes on Matrigel. Flow cytometry results indicated that CD133 expression was highest at day 12 and that the greatest number of cells positive for both FLK-1 and CD133 appeared at day 20 from cells cultured in dishes without fibronectin coating. In addition, the expression levels of CD133, CD31 and FLK-1/CD133 were not significantly different between cells of different shapes. Our experiments suggest that MNCs from bone marrow can be differentiated into late EP-like cells in EGM-2MV, which have the ability to rapidly proliferate. These MNCs can also be differentiated into early EP-like cells in CM. Additionally, fibronectin may not be necessary for the differentiation of EPCs to mature ECs after three generations. Differentiated MNCs from bone marrow in EGM-2MV have the characteristics of EPCs, although the expression levels of EPC markers were lower than previously reported. [ABSTRACT FROM AUTHOR]