hUMSCs restore ovarian function in POI mice by regulating GSK3ß-mediated mitochondrial dynamic imbalances in theca cells.

Premature ovarian insufficiency (POI), a major cause of female infertility, is defined as follicular atresia and a rapid loss of germ cells in women of reproductive age due to ovarian failure. Recently, findings from several studies have indicated that human umbilical cord mesenchymal stem cells (hUMSCs) can alleviate ovarian dysfunction resulting from POI. However, the mechanisms underlying this effect require further clarification. In this study, a mouse model of POI was established as achieved with an intraperitoneal injection of cyclophosphamide (CTX) into female C57BL/6J mice in vivo. These POI mice received a 1-week intervention of hUMACs. In addition, an in vitro POI model was also included. The cultured supernatants of hUMSCs and glycogen synthase kinase 3 beta (GSK3ß) inhibitor (SB216763) were used to treat theca cells (TCs) exposed to CTX. Hematoxylin and Eosin (H&E) staining and Enzyme-linked immunosorbent assay (ELISA) were used to assess ovarian structure and morphology, as well as endocrine function in these POI mice. Based on results from the ELISA and JC-1 labeling, CTX exerted significant detrimental effects on testosterone levels and the mitochondrial membrane potential in TCs. Subsequently, Western Blot, Immunofluorescence staining (IF), and Quantitative real-time polymerase chain reaction (qRT-PCR) were used to evaluate various indicators of testosterone synthesis function and mitochondrial dynamics in ovaries and TCs of POI mice. In vivo, dysfunctions in ovarian structure and function in the POI mouse model were effectively restored following hUMSCs treatment, and abnormalities in hormone synthesis were significantly reduced. Furthermore, when the stem cell supernatants of hUMSCs were applied to TCs in vitro we found that GSK3ß expression was reduced, the imbalance of mitochondrial dynamics was alleviated, and the ability of mitochondrial testosterone synthesis was increased. Taken together, our results indicate that hUMSCs treatment can restore the imbalance of mitochondrial dynamics and restart testosterone synthesis of TCs by suppressing GSK3ß expression, ultimately alleviating POI damage.

hPMSCs prevent erythrocytes dysfunction caused by graft versus host disease via promoting GSH synthesis.

BACKGROUND: Oxidative stress is increased in allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients and leads to the development of graft versus host disease (GVHD). Mesenchymal stromal cells (MSCs) can ameliorate GVHD by regulating the function of T cells. However, whether MSCs can modulate erythrocyte antioxidant metabolism and thus reduce GVHD is not known. METHODS: Forty female BALB/c mice were randomly assigned to four groups: the control, GVHDhigh, hPMSC, and PBS groups. A hypoxanthine/xanthine oxidase system was used to steadily and gradually produce superoxide in an in vitro experiment. A scanning microscope was used to examine the ultrastructure of erythrocytes. Laser diffraction analyses were used to analyze erythrocyte deformability. Western blotting was used to measure the expression of the erythrocyte membrane skeleton proteins Band 3 and ß-Spectrin. Corresponding kits were used to assess the levels of oxidative damage and the activity of antioxidant enzymes. RESULTS: Morphological and deformability defects were significantly increased in erythrocytes from GVHD patients. Band 3 and ß-Spectrin expression was also reduced in GVHD patients and model mice. Furthermore, we observed significantly increased oxidative stress-induce injury and decreased antioxidant capability in erythrocytes from both GVHD patients and model mice. Subsequent research showed that human placenta-derived MSC (hPMSC) therapy decreased the GVHD-induced redox imbalance in erythrocytes. Furthermore, our findings suggested that upregulating glucose metabolism promoted both the de novo synthesis and recycling of GSH, which is the primary mechanism by which hPMSCs mediate the increase in antioxidant capacity in erythrocytes. CONCLUSION: Together, our findings suggest that hPMSCs can increase antioxidant capacity by increasing erythrocyte GSH production and thus ameliorate GVHD.

hUCMSC-derived exosomes protect against GVHD-induced endoplasmic reticulum stress in CD4+ T cells by targeting the miR-16-5p/ATF6/CHOP axis.

Exosomes generated from mesenchymal stem cells (MSCs) are thought to be a unique therapeutic strategy for several autoimmune deficiency illnesses. The purpose of this study was to elucidate the protective effects of human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-Exo) on CD4+ T cells dysfunction during graft-versus-host disease (GVHD) and to identify the underlying processes involved. Here, we showed that hUCMSC-Exo treatment can effectively attenuate GVHD injury by alleviating redox metabolism disorders and inflammatory cytokine bursts in CD4+ T cells. Furthermore, hUCMSC-Exo ameliorate ER stress and ATF6/CHOP signaling-mediated apoptosis in CD4+ T cells and promote the development of CD4+IL-10+ T cells during GVHD. Moreover, downregulating miR-16-5p in hUCMSC-Exo impaired their ability to prevent CD4+ T cells apoptosis and weakened their ability to promote the differentiation of CD4+IL-10+ T cells. Collectively, the obtained data suggested that hUCMSC-Exo suppress ATF6/CHOP signaling-mediated ER stress and apoptosis in CD4+ T cells, enhance the differentiation of CD4+IL-10+ T cells, and reverse the imbalance of immune homeostasis in the GVHD process by transferring miR-16-5p. Our study provided further evidence that GVHD patients can benefit from hUCMSC-Exo-mediated therapy.

hPMSCs-Derived Exosomal miRNA-21 Protects Against Aging-Related Oxidative Damage of CD4+ T Cells by Targeting the PTEN/PI3K-Nrf2 Axis.

Mesenchymal stem cells (MSCs)-derived exosomes were considered a novel therapeutic approach in many aging-related diseases. This study aimed to clarify the protective effects of human placenta MSCs-derived exosomes (hPMSC-Exo) in aging-related CD4+ T cell senescence and identified the underlying mechanisms using a D-gal induced mouse aging model. Senescent T cells were detected SA-ß-gal stain. The degree of DNA damage was evaluated by detecting the level of 8-OH-dG. The superoxide dismutase (SOD) and total antioxidant capacity (T-AOC) activities were measured. The expression of aging-related proteins and senescence-associated secretory phenotype (SASP) were detected by Western blot and RT-PCR. We found that hPMSC-Exo treatment markedly decreased oxidative stress damage (ROS and 8-OH-dG), SA-ß-gal positive cell number, aging-related protein expression (p53 and γ-H2AX), and SASP expression (IL-6 and OPN) in senescent CD4+ T cells. Additionally, hPMSC-Exo containing miR-21 effectively downregulated the expression of PTEN, increased p-PI3K and p-AKT expression, and Nrf2 nuclear translocation and the expression of downstream target genes (NQO1 and HO-1) in senescent CD4+ T cells. Furthermore, in vitro studies uncovered that hPMSC-Exo attenuated CD4+ T cell senescence by improving the PTEN/PI3K-Nrf2 axis by using the PTEN inhibitor bpV (HOpic). We also validated that PTEN was a target of miR-21 by using a luciferase reporter assay. Collectively, the obtained results suggested that hPMSC-Exo attenuates CD4+ T cells senescence via carrying miRNA-21 and activating PTEN/PI3K-Nrf2 axis mediated exogenous antioxidant defenses.

hPMSCs inhibit the expression of PD-1 in CD4+IL-10+ T cells and mitigate liver damage in a GVHD mouse model by regulating the crosstalk between Nrf2 and NF-κB signaling pathway.

BACKGROUND: The activation of T cells and imbalanced redox metabolism enhances the development of graft-versus-host disease (GVHD). Human placenta-derived mesenchymal stromal cells (hPMSCs) can improve GVHD through regulating T cell responses. However, whether hPMSCs balance the redox metabolism of CD4+IL-10+ T cells and liver tissue and alleviate GVHD remains unclear. This study aimed to investigate the effect of hPMSC-mediated treatment of GVHD associated with CD4+IL-10+ T cell generation via control of redox metabolism and PD-1 expression and whether the Nrf2 and NF-κB signaling pathways were both involved in the process. METHODS: A GVHD mouse model was induced using 6-8-week-old C57BL/6 and Balb/c mice, which were treated with hPMSCs. In order to observe whether hPMSCs affect the generation of CD4+IL-10+ T cells via control of redox metabolism and PD-1 expression, a CD4+IL-10+ T cell culture system was induced using human naive CD4+ T cells. The percentage of CD4+IL-10+ T cells and their PD-1 expression levels were determined in vivo and in vitro using flow cytometry, and Nrf2, HO-1, NQO1, GCLC, GCLM, and NF-κB levels were determined by western blotting, qRT-PCR, and immunofluorescence, respectively. Hematoxylin-eosin, Masson's trichrome, and periodic acid-Schiff staining methods were employed to analyze the changes in hepatic tissue. RESULTS: A decreased activity of superoxide dismutase (SOD) and a proportion of CD4+IL-10+ T cells with increased PD-1 expression were observed in GVHD patients and the mouse model. Treatment with hPMSCs increased SOD activity and GCL and GSH levels in the GVHD mouse model. The percentage of CD4+IL-10+ T cells with decreased PD-1 expression, as well as Nrf2, HO-1, NQO1, GCLC, and GCLM levels, both in the GVHD mouse model and in the process of CD4+IL-10+ T cell generation, were also increased, but NF-κB phosphorylation and nuclear translocation were inhibited after treatment with hPMSCs, which was accompanied by improvement of hepatic histopathological changes. CONCLUSIONS: The findings suggested that hPMSC-mediated redox metabolism balance and decreased PD-1 expression in CD4+IL-10+ T cells were achieved by controlling the crosstalk between Nrf2 and NF-κB, which further provided evidence for the application of hPMSC-mediated treatment of GVHD.

hPMSCs protects against D-galactose-induced oxidative damage of CD4+ T cells through activating Akt-mediated Nrf2 antioxidant signaling.

BACKGROUND: Mesenchymal stem cells (MSCs) were considered a regenerative therapeutic approach in both acute and chronic diseases. However, whether MSCs regulate the antioxidant metabolism of CD4+ T cells and weaken immunosenescence remains unclear. Here, we reported the protective effects of hPMSCs in aging-related CD4+ T cell senescence and identified the underlying mechanisms using a D-gal-induced mouse aging model. METHODS: In vivo study, 40 male C57BL/6 mice (8 weeks) were randomly divided into four groups: control group, D-gal group, hPMSC group, and PBS group. In in vitro experiment, human naive CD4+ T (CD4CD45RA) cells were prepared using a naive CD4+ T cell isolation kit II and pretreated with the Akt inhibitor LY294002 and Nrf2 inhibitor ML385. Then, isolated naive CD4+ T cell were co-cultured with hPMSCs for 72 h in the absence or presence of anti-CD3/CD28 Dynabeads and IL-2 as a mitogenic stimulus. Intracellular ROS changes were detected by flow cytometry. The activities of the antioxidant enzymes superoxide dismutase, glutathione peroxidase, and catalase were measured by colorimetric analysis. The senescent T cells were detected SA-ß-gal stain. The expression of aging-related proteins was detected by Western blotting, RT-PCR, and confocal microscopy. RESULTS: We found that hPMSC treatment markedly decreased the ROS level, SA-ß-gal-positive cells number, senescence-associated secretory phenotype (IL-6 and OPN) expression, and aging-related protein (P16 and P21) expression in senescent CD4+ T cells. Furthermore, hPMSC treatment effectively upregulated Nrf2 nuclear translocation and the expression of downstream target genes (HO-1, CAT, GCLC, and NQO1) in senescent CD4+ T cells. Moreover, in vitro studies revealed that hPMSCs attenuated CD4+ T cell senescence by upregulating the Akt/GSK-3ß/Fyn pathway to activate Nrf2 functions. Conversely, the antioxidant effects of hPMSCs were blocked by the Akt inhibitor LY294002 and Nrf2 inhibitor ML385 in senescent CD4+ T cells. CONCLUSIONS: Our results indicate that hPMSCs attenuate D-gal-induced CD4+ T cell senescence by activating Nrf2-mediated antioxidant defenses and that upregulation of Nrf2 by hPMSCs is regulated via the Akt/GSK-3ß/Fyn pathway.

Downregulated Recycling Process but Not De Novo Synthesis of Glutathione Limits Antioxidant Capacity of Erythrocytes in Hypoxia.

Red blood cells (RBCs) are susceptible to sustained free radical damage during circulation, while the changes of antioxidant capacity and regulatory mechanism of RBCs under different oxygen gradients remain unclear. Here, we investigated the changes of oxidative damage and antioxidant capacity of RBCs in different oxygen gradients and identified the underlying mechanisms using an in vitro model of the hypoxanthine/xanthine oxidase (HX/XO) system. In the present study, we reported that the hypoxic RBCs showed much higher oxidative stress injury and lower antioxidant capacity compared with normoxic RBCs. In addition, we found that the disturbance of the recycling process, but not de novo synthesis of glutathione (GSH), accounted for the significantly decreased antioxidant capacity of hypoxic RBCs compared to normoxic RBCs. We further elucidated the underlying molecular mechanism by which oxidative phosphorylation of Band 3 blocked the hexose monophosphate pathway (HMP) and decreased NADPH production aggravating the dysfunction of GSH synthesis in hypoxic RBCs under oxidative conditions.

Oligosaccharide attenuates aging-related liver dysfunction by activating Nrf2 antioxidant signaling.

Chitosan oligosaccharide (COS) is the depolymerized product of chitosan possessing various biological activities and protective effects against inflammation and oxidative injury. The aim of the present study was to investigate the antioxidant effects of COS supplements on aging-related liver dysfunction. We found that COS treatment significantly attenuated elevated liver function biomarkers and oxidative stress biomarkers and decreased antioxidative enzyme activities in liver tissues in D-galactose (D-gal)-treated mice. Furthermore, COS treatment significantly upregulated the expression of Nrf2 and its downstream target genes HO-1, NQO1, and CAT. Moreover, in vitro experiments showed that COS treatment played a vital role in protecting H2O2-exposed L02 cells against oxidative stress by activating Nrf2 antioxidant signaling. These data indicate that COS could protect against D-gal-induced hepatic aging by activating Nrf2 antioxidant signaling, which may provide novel applications for the prevention and treatment of aging-related hepatic dysfunction.

IL-1ß enhances human placenta-derived mesenchymal stromal cells ability to mediate Th1/Th2 and Th1/CD4+IL-10+ T cell balance and regulates its adhesion, proliferation and migration via PD-L1.

Human placenta-derived mesenchymal stromal cells (hPMSCs) are promising candidates for the treatment of graft-versus-host disease (GVHD), which is associated with high IL-1ß levels. In this study, the effects of IL-1ß and hPMSCs on each other were investigated by analyzing the proportion of Th1, Th2 and CD4+IL-10+ T cells and PD-L1 expression, as well as the adhesion, migration, and proliferation of hPMSCs. The results showed that hPMSCs decreased IL-1ß levels and downregulated Th1/Th2 and Th1/CD4+IL-10+ T cells ratios in the GVHD model. The in vitro results revealed that IL-1ß strengthened the hPMSCs capacity to reduce the Th1/Th2 and Th1/CD4+IL-10+ T cell ratios, inhibited the adhesion and proliferation of hPMSCs and increased PD-L1 expression on hPMSCs via the JAK and NF-κB pathways. Overall, these findings suggested that hPMSCs alleviate GVHD by decreasing IL-1ß level and maintaining the balance among different T cell subsets. IL-1ß enhanced the ability of hPMSCs to balance different T cell subsets and inhibited hPMSCs adhesion and proliferation by regulating PD-L1 expression via the JAK and NF-κB pathways.

Elevated SH3BP5 Correlates with Poor Outcome and Contributes to the Growth of Acute Myeloid Leukemia Cells.

Current strategies are not especially successful in the treatment of acute myeloid leukemia (AML). The identification and characterization of oncogenes crucial to the survival and growth of leukemia cells will provide potential targets for the exploitation of novel therapies. Herein, we report that the elevated expression of SH3 domain-binding protein 5 (SH3BP5) significantly correlates with poor outcomes of AML patients. To test whether SH3BP5 contributes to the growth and survival of AML cells, we use the shRNA-encoding lentivirus system to achieve the knockdown of SH3BP5 expression in human AML cell lines U937, THP-1, Kasumi-1, and MV4-11. Functionally, the knockdown of SH3BP5 expression markedly inhibits the cell viability and induced apoptosis of these leukemia cells. Mechanistically, western blot analysis indicates that the knockdown of SH3BP5 expression decreases the phosphorylation of JNK and BAD. Moreover, the JNK agonist anisomycin rescues the growth inhibition phenotype of SH3BP5 deficiency in THP-1 cells. Moreover, the expression of SH3BP5 positively correlates with CD25 and CD123 levels. Finally, our study highlights the crucial role of SH3BP5 in promoting the survival of AML cells, and its suppression may be a potential therapeutic strategy for treating human AML.

IL-27 Promotes Human Placenta-Derived Mesenchymal Stromal Cell Ability To Induce the Generation of CD4+IL-10+IFN-γ+ T Cells via the JAK/STAT Pathway in the Treatment of Experimental Graft-versus-Host Disease.

Human mesenchymal stromal cells (MSCs) harbor immunomodulatory properties to induce the generation of suppressive T cells. MSCs have been successfully used in treating graft-versus-host disease (GVHD) accompanied by abundant inflammatory cytokines such as IL-27. This study investigated the effects of IL-27 on the human placenta-derived MSCs (hPMSCs) to induce generation of CD4+IL-10+IFN-γ+ T cells in vitro and in the humanized xenogenic GVHD NOD/SCID model. The results showed that the percentages of CD4+IL-10+IFN-γ+ T cells were significantly increased in activated human PBMC from both healthy donors and GVHD patients with hPMSCs and in the liver and spleen of hPMSC-treated GVHD mice, and the level of CD4+IL-10+IFN-γ+ T cells in the liver was greater than that in the spleen in hPMSC-treated GVHD mice. The serum level of IL-27 decreased and the symptoms abated in hPMSC-treated GVHD. Further, in vitro results showed that IL-27 promoted the regulatory effects of hPMSCs by enhancing the generation of CD4+IL-10+IFN-γ+ T cells from activated PBMC. Activation occurred through increases in the expression of programmed death ligand 2 (PDL2) in hPMSCs via the JAK/STAT signaling pathway. These findings indicated that hPMSCs could alleviate GVHD mice symptoms by upregulating the production of CD4+IL-10+IFN-γ+ T cells in the spleen and liver and downregulating serum levels of IL-27. In turn, the ability of hPMSCs to induce the generation of CD4+IL-10+IFN-γ+ T cells could be promoted by IL-27 through increases in PDL2 expression in hPMSCs. The results of this study will be of benefit for the application of hPMSCs in clinical trials.

Repair of Peripheral Nerve Sensory Impairments via the Transplantation of Bone Marrow Neural Tissue-Committed Stem Cell-Derived Sensory Neurons.

The present study aimed to investigate the efficacy of transplantation of bone marrow neural tissue-committed stem cell-derived sensory neuron-like cells for the repair of peripheral nerve sensory impairments in rats. Bone marrow was isolated and cultured to obtain the neural tissue-committed stem cells (NTCSCs), and the differentiation of these cells into sensory neuron-like cells was induced. Bone marrow mesenchymal stem cells (BMSCs), bone marrow NTCSCs, and bone marrow NTCSC-derived sensory neurons (NTCSC-SNs) were transplanted by microinjection into the L4 and L5 dorsal root ganglions (DRGs) in an animal model of sensory defect. On the 2nd, 4th, 8th, and 12th week after the transplantation, the effects of the three types of stem cells on the repair of the sensory functional defect were analyzed via behavioral observation, sensory function evaluation, electrophysiological examination of the sciatic nerve, and morphological observation of the DRGs. The results revealed that the transplanted BMSCs, NTCSCs, and NTCSC-SNs were all able to repair the sensory nerves. In addition, the effect of the NTCSC-SNs was significantly better than that of the other two types of stem cells. The general posture and gait of the animals in the sensory defect model exhibited evident improvement over time. Plantar temperature sensitivity and pain sensitivity gradually recovered, and the sensation latency was reduced, with faster sensory nerve conduction velocity. Transplantation of NTCSC-SNs can improve the repair of peripheral nerve sensory defects in rats.

Hydroxysafflor yellow A suppresses angiogenesis of hepatocellular carcinoma through inhibition of p38 MAPK phosphorylation.

The antitumor effect of hydroxysafflor yellow A (HSYA), an active ingredient of the herb Carthamus tinctorius L. (Asteraceae) (safflower), was investigated in the current work. Researches of HSYA on vasculogenesis inhibition, along with the related molecular mechanisms, including the expression of MMP-2, MMP-9, and p38MAPK (COX-2, ATF-2, p-p38MAPK, and p38MAPK) signaling pathway in H22 tumor-bearing mice or HepG2 cells were performed. The animal experiments proved the level of MMP-2 and MMP-9 in H22-transplanted tumor tissue in mice markedly decreased by HSYA, and results both in vivo and in vitro confirmed that COX-2 expression was reduced significantly via p38MAPK|ATF-2 signaling pathway. According to the outcomes, HSYA suppressed p38MAPK phosphorylation in a concentration-dependent manner, while exerting no effect on the total p38MAPK protein expression. It was also showed that suppression of p38 activation by SB203580 decreased the HepG2 cell viability, proliferation, and migration, wherein HSYA exhibited a similar effect. Furthermore, Western blot analysis on caspase-3 and cleaved-caspase-3 revealed that HSYA could induce apoptosis of HepG2 cells. These findings provided experimental evidences that HSYA might be a promising anticancer agent for HCC.

Inhibition of Glutathione Synthesis via Decreased Glucose Metabolism in Stored RBCs.

BACKGROUND/AIMS: Although red blood cells (RBCs) transfusions can be lifesaving, they are not without risk. RBCs storage is associated with the abnormal metabolism of glutathione (GSH), which may increase the risk of the oxidative damage of RBCs after transfusion. The responsible mechanisms remain unknown. METHODS: We determined the L-cysteine efflux and influx by evaluating the changes of free -SH concentrations in stored RBCs. The glutamate cysteine ligase (GCL) activities and protein content in stored RBCs was determined by fluorescence assay and western blotting. In addition, the glucose metabolism enzyme activity of RBCs was measured by spectrophotometric assay under in vitro incubation conditions. RESULTS: We found that both L-cysteine transport and GCL activity significantly declined, thereby inducing the dysfunction of GSH synthesis during blood storage, which could be attenuated by ATP supplement and DTT treatment. In addition, the glycometabolic enzyme (G6PDH, HK, PK and LDH) activity significantly decreased after 6 weeks storage. Oxidant stress-induced dysfunction in glucose metabolism was the driving force for decreased GSH synthesis during storage. CONCLUSION: These experimental findings reflect an underlying molecular mechanism that oxidant stress induced glucose metabolism dysfunction contribute to decreased GSH synthesis in stored RBCs.

Vitamin C and E Supplements Enhance the Antioxidant Capacity of Erythrocytes Obtained from Aged Rats.

BACKGROUND/AIMS: The main purpose of the present study was to investigate the effects of vitamin C and E supplements on the antioxidant capacity of erythrocytes obtained from young and aged rats. METHODS: Male Wistar rats aged 3 and 24 months were used. Vitamins C and E were injected at doses of 200 mg/kg (day) intraperitoneally in young and aged groups. The antioxidant capacity, oxidant stress parameters, and deformability of red blood cells collected from different age stages were evaluated. An in vitro oxidation system was constructed to explore the mechanisms of antioxidant capacity change in the vitamin treatment groups. RESULTS: Treatment with vitamins C and E can effectively restore the antioxidant capacity and deformability of red blood cells (RBCs) in aged rats. Under in vitro oxidative conditions, an age-dependent decline in the influx rate of L-cysteine was observed. This was significantly improved following treatment with vitamins C and E. CONCLUSION: We present evidence of an improvement in the antioxidant capacity of RBCs by treatment with vitamins C and E in aged rats. These observations also suggest that treatment with vitamins C and E improves glutathione synthesis by enhancing the influx rate of L-cysteine through the modification of membrane proteins and lipids.

Inhibition of Glutathione Synthesis Induced by Exhaustive Running Exercise via the Decreased Influx Rate of L-Cysteine in Rat Erythrocytes.

BACKGROUND/AIMS: The main purpose of this study was to investigate the effect of exhaustive exercise on L-cysteine uptake and its effect on erythrocyte glutathione (GSH) synthesis and metabolism. METHODS: Rats were divided into three groups: sedentary control (C), exhaustive running exercise (ERE) and moderate running exercise (MRE) (n=12 rats/group). We determined the L-cysteine efflux and influx in vitro in rat erythrocytes and its relationship with GSH synthesis. Total anti-oxidant potential of plasma was measured in terms of the ferric reducing ability of plasma (FRAP) values for each exercise group. In addition, the glucose metabolism enzyme activity of erythrocytes was also measured under in vitro incubation conditions. RESULTS: Biochemical studies confirmed that exhaustive running exercise significantly increased oxidative damage parameters in thiobarbituric acid reactive substances (TBARS) and methemoglobin levels. Pearson correlation analysis suggested that L-cysteine influx was positively correlated with erythrocyte GSH synthesis and FRAP values in both the control and exercise groups. In vitro oxidation incubation significantly decreased the level of glucose metabolism enzyme activity in the control group. CONCLUSION: We presented evidence of the exhaustive exercise-induced inhibition of GSH synthesis due to a dysfunction in L-cysteine transport. In addition, oxidative stress-induced changes in glucose metabolism were the driving force underlying decreased L-cysteine uptake in the exhaustive exercise group.

[Increased oxidative damages of erythrocytes caused by declined blood oxygen saturation].

This paper was to explore the effect of blood oxygen saturation (SO2) on oxidative damages of erythrocytes under the condition of oxidative stress. Keeping SO2 of cultured erythrocytes in vitro at the states of 0.3, 0.5, 0.7, 0.9 and 0.98, respectively, we induced oxidative stress by tert-buthylhydroperoxide (BHP, 0.15 mmol/L of final concentration). After incubation, antioxidant capacity was assessed by measuring content of reduced glutathin hormone (GSH) in erythrocytes. Methemoglobin (MetHb) content, lipid peroxidation (thiobarbituric acid-reactive substances, TBARS) and denatured globin-chains on the plasma membrane were measured to assess the extent of oxidative damages. The results showed that in the presence of BHP, GSH contents increased from 0.3 to 0.98 groups; MetHb, TBARS and globin-chains levels all dropped with the rise of SO2. In conclusion, antioxidant capacity and oxidative damages of erythrocytes are closely related to SO2, declined SO2 could promote oxidative damages of erythrocytes.