Leptin protects rat cardiomyocytes from H2O2-induced apoptosis

AIM: To investigate the effect of leptin on H₂O₂-induced apoptosis in rat cardiomyocytes (H9c2 cells) and the underlying mechanisms.METHODS: Terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) was used to determine H₂O₂-induced apoptosis in H9c2 cells in the absence or presence of leptin. The activities of caspase-3 and extracellular signal-regulated kinase (ERK) were examined by Western blotting.RESULTS: (1)Leptin significantly inhibited H₂O₂-induced apoptosis in H9c2 cells (P<0.01). This effect of leptin was opposed by MEK inhibitor PD98059. (2)H₂O₂ inhibited basal ERK activity. Leptin activated ERK and partially inhibited H₂O₂-induced caspase-3 activation.CONCLUSION: Leptin protects H9c2 cells from H₂O₂-induced apoptosis possibly by activating ERK.     

Adiponectin activates AKT and protects rat cardiomyocytes against H2O2-induced apoptosis

AIM: To study the effect of adiponectin on H₂O₂-induced apoptosis in rat cardiomyocytes (H9c2 cells). METHODS: Terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) was used to determine H₂O₂-induced apoptosis of H9c2 cells in the absence or presence of adiponectin. The content of caspase-3 and Akt (protein kinase B, PKB) was examined by Western blotting. RESULTS: Adiponectin significantly inhibited H₂O₂-induced apoptosis in H9c2 cells (P<0.01). Adiponectin increased basal and H₂O₂-induced Akt activity and significantly inhibited H₂O₂-induced activation of caspase-3 (P<0.01). Pretreatment with LY294002, a specific inhibitor of Akt upstream kinase PI3K (phosphatidylinositol 3-kinase), not only increased H₂O₂-induced H9c2 cell apoptosis, but also abrogated the anti-apoptotic effect of adiponectin. CONCLUSION: Adiponectin protects H9c2 cells against H₂O₂-induced apoptosis by activating PI3K/Akt signaling pathway.     

Protective effects of nmhaFGF on NRK52E cell apoptosis induced by H2O2

AIM: The present study was designed to establish H2O2-induced NRK52E cell apoptotic model and to investigate the effects and the mechanism of nmhaFGF on the NRK52E cell apoptosis induced by H2O2. METHODS: In vitro experiment, a apoptotic model of normal rat kidney epithelium (NRK52E) was made by MTT method, Hoechst33342 dyeing and flow cytosorting (FCR). NRK52E cells were cultured with different concentrations of nmhaFGF and haFGF for 24 h before H2O2 was added. The apoptotic rate was detected with FCR method. RESULTS: H2O2 at concentration of 0.4 mmol/L, the optimal condition to establish the apoptotic model, was used to treat NRK52E cells for 18h. Different doses of nmhaFGF (0.01, 0.03, 0.10, 0.30, 1.00 mg/L) reduced the apoptotic rates with the dose rising. However, the decreasing tends of apoptotic rates with dose increasing for haFGF was not so obvious. CONCLUSION: nmhaFGF protects the NRK52E cells against apoptosis. The mechanism might be connected with its non-mitogenic property.     

Effects of luteolin on endothelial cell injury induced by H2O2

AIM: To study the effect of luteolin on endothelial cell injuries induced by H₂O₂. METHODS: Endothelial cells were cultured in vitro and divided into seven groups: control; solvent; H₂O₂; quercetin+H₂O₂; luteolin-L+H₂O₂; luteolin-M+H₂O₂; luteolin-H+H₂O₂ group, respectively. Endothelial cells were incubated with 750 μmol/L H₂O₂ for 18 h or 14 h in the absence or presence of various concentrations of luteolin and quercetin. The expression of caspase-3, the pro-apoptotic factors, was detected by immunohistochemical technique, and the apoptotic index was detected by flow cytometry. Meanwhile, the amount of malondialdehyde (MDA), nitric oxide (NO), lacate dehydrogenase (LDH) in serum, and cell viability were measured. RESULTS: Incubation of endothelial cells with H₂O₂ for 18 h elicited the increase in the extent of immunostaining for caspase-3, the rate of apoptosis, the release of LDH, and the number of dead cells accompanied by the decrease in the content of NO in the medium, which were inhibited by pretreatment of luteolin at concentrations of 0.5-50 μmol/L in a concentration-dependent manner (P<0.01). CONCLUSION: Luteolin possesses a protective effect against endothelial cell injuries induced by H₂O₂, which may be related with anti-oxidation, increasing the concentration of NO and inhibiting the activation of caspase-3.     

Effect of H2O2 on voltage-gated potassium channels in rat pulmonary artery smooth muscle cells

AIM:To determine the effect of hydrogen peroxide (H₂O₂) on voltage-gated potassium channel currents (IKv) in pulmonary vascular smooth muscle cells (PASMCs). METHODS:Using whole cell patch-clamp technique, IKv was recorded in freshly isolated rat PASMCs with acute enzymatic digestion method. The effect of hydrogen peroxide on IKv in PASMCs was investigated in normoxia. RESULTS:IKv in PASMCs was increased significantly by H₂O₂ and the increase depended on the concentration in normoxia. Current-voltage relationship curve shifted to the left. CONCLUSION:Hydrogen peroxide is an important K+ channel opener.     

VEGF induces HUVECs to produce extracellular H2O2 and its proliferation role

AIM:To study the effect of VEGF on extracellular H₂O₂ production in HUVECs and the role of H₂O₂ in the VEGF-induced proliferation. METHODS:HUVECs was stimulated with 500 μg/L VEGF. Products of extracellular H₂O₂ was detected by H₂DCFDA staining. MTT method was used to value the influences of 3×10⁶ U/L catalase and 5-20 mmol/L H₂O₂ to VEGF function. RESULTS:After treatment for 15 min with VEGF, HUVECs appeared fluorescence, and continued to become stronger, peaked at 45 min then decreased. HUVECs, which was treated simultaneity with VEGF and 3×10⁶ U/L catalase, only appeared very faint fluorescence. The proliferation of HUVECs by VEGF was restrained when treated with 3×10⁶ U/L catalase. The extrinsic H₂O₂ at concentration of 5-10 mmol/L promoted the proliferation of HUVECs but inhibited the proliferation effect of VEGF on HUVECs (P<0.01). CONCLUSION:These findings indicate that VEGF induces HUVECs to produce extracellular H₂O₂ and plays role in proliferation, but extrinsic H₂O₂ restrains VEGF function.     

Role of ERK1/2-STAT3 pathway in adaptive cytoprotection induced by H2O2 preconditioning

AIM:To explore the role of extracellular signal-regulated kinases ERK1/2-STAT3 pathway in adaptive cytoprotection induced by H₂O₂ preconditioning in PC12 cells. METHODS:In PC12 cells, the experimental model of cytoprotection by H₂O₂ preconditioning against oxidative stress-induced injury was set up. The morphological changes in the apoptotic cells were observed by using of chromatin dye Hoechst 33258. The percent of apoptotic cells was determined by flow cytometry (FCM) with propidium iodide staining. The levels of p-ERK1/2 and p-STAT3 expression were detected by Western blotting assay. RESULTS:Preconditioning with H₂O₂ at concentration of 100 μmol/L for 90 min obviously inhibited apoptosis induced by 300 μmol/L H₂O₂, and both ERK1/2 and STAT3 were activated. UO126 (10 μmol/L, an inhibitor of ERK1/2) or AG-490 (10μmol/L, an inhibitor of JAK2) significantly blocked the cytoprotection effect of H₂O₂ preconditioning. Moreover, UO126 (10 μmol/L) also markedly inhibited the up-regulation of p-STAT3 expression by H₂O₂ preconditioning. CONCLUSION:H₂O₂ preconditioning activates ERK1/2-STAT3 signal pathway, which may be one of the mechanisms underlying H₂O₂ preconditioning-induced cytoprotection.     

Changes of NO- and H2O2-dependent soluble guanylate cyclase pathway in the hypoxic hypercapnic pulmonary hypertension rats

AIM: To study the effect of hypoxia and hypercapnia on nitric oxide (NO) in plasma and superoxide dismutase (SOD), catalase (CAT), soluble guanylate cyclase (sGC), cyclic guanosine monophospholate (cGMP) in lung tissue in rats, and to explore the effect of NO- and H2O2-sGC pathway on the development of the pulmonary hypertension. METHODS: The model of hypoxic and hypercapnic 1, 2, 4-week group (HH 1 week, HH 2 weeks, HH 4 weeks) and control group was set up. NO content in plasma, CAT and SOD in rat lung were determined by spectrophotometry. The sGC activity in lung tissue was detected by enzyme kinetic analysis. cGMP content in lung tissue was examined with ［125I］-radioimmunoassay. RESULTS: The mean pulmonary artery pressure (mPAP) showed significantly higher in HH 1 week, HH 2 weeks and HH 4 weeks groups compared with control group (all P<0.05). NO concentration in plasma, CAT, SOD, basal or nitroprusside-or H2O2- stimulated sGC activity and cGMP concentration in lung homogenates were significantly lower (P<0.05, P<0.01, P<0.01, respectively) in HH 1 week, HH 2 weeks and HH 4 weeks groups compared with control group. CONCLUSION: The inhibition of NO- and H2O2-sGC pathway by hypoxia and hypercapnia plays an important role in the development of pulmonary hypertension.     

Acetyl-L-carnitine attenuates H2O2-induced oxidative damage of PC12 cells

AIM: To investigate the effect of acetyl-L-carnitine (ALC) on H₂O₂-induced oxidative damage in PC12 cells and its possible mechanism. METHODS: A moderate oxidative damage PC12 cell model was induced by exposure of the PC12 cells to H₂O₂. ALC at different concentrations (100, 200 and 400 μmol/L) was applied to the PC12 cells cultured in vitro, and CCK8 assay was used to detect the cell viability. The cells were divided into control group, H₂O₂ group, and low-ALC, medium-ALC and high-ALC groups. The apoptosis of the cells was analyzed by flow cytometry. The protein levels of Nrf2 and cleaved caspase-3 were determined by Western blot. The nuclear translocation of Nrf2 was observed by immunofluorescence staining. RESULTS: ALC at different concentrations (100, 200 and 400 μmol/L) significantly inhibited H₂O₂-induced PC12 cell apoptosis, and the medium concentration group had the best effect. Compared with H₂O₂ group, low, medium and high concentrations of ALC significantly increased the viability of the PC12 cells induced by H₂O₂, inhibit cell apoptosis (P<0.05), significantly down-regulated the protein level of cleaved caspase-3 (P<0.05), up-regulated the protein level of Nrf2 (P<0.05), and promoted the translocation of Nrf2 from the cytoplasm to the nucleus. CONCLUSION: Acetyl-L-carnitine attenuates H₂O₂-induced oxidative damage of PC12 cells, inhibits the apoptosis and increases the viability, which is related to the activation of Nrf2 signaling pathway.     

Effect of NPPB and niflumic acid on expression of GCL and CLIC4 in H2O2 injured C6 glioma cells

AIM: To observe the effect of 5-nitro-2- (3-phenylpropylamino) benzoate acid (NPPB), niflumic acid (NFA) (chloride channel blockers) on malignant glioma C6 cells injured by hydrogen peroxide (H₂O₂). METHODS: The viability of C6 cells treated with NPPB, NFA and H₂O₂ was measured by MTT assay. LDH release rate and GSH contents were detected by ultraviolet spectrophotometry. mRNA levels of GCLC, GCLM and CLIC4 were determined by RT-PCR. CLIC4 protein level was detected by Western blotting. RESULTS: Compared to the control group, H₂O₂ treatment induced the decrease in cell viability and GSH contents, the increase in LDH release rate, the decrease in the expression of GCLC, GCLM and CLIC4 mRNA and the increase in CLIC4 protein level (P<0.05 ), respectively. Compared with the H₂O₂ group, H₂O₂ combined with NPPB or NFA treatment did not change the cell viability, the GSH contents and the GCLC, GCLM mRNA expression. However, the LDH release rate and CLIC4 protein level decreased (P<0.05). CONCLUSION: The chloride channel blockers NPPB or NFA lessen the oxidative injury of C6 cells through modulating the function of membrane and down-regulating the protein expression of CLIC4.     

Effect of diazoxide on change of H2O2 in rat pulmonary artery smooth muscle cells and proliferation of hypoxic rat pulmonary artery smooth muscle cells

AIM: To investigate the contribution of diazoxide,an opener of mitochondrial ATP-sensitive K+ channel (MitoK_ATP),and mitochondrial membrane potential (ΔΨm) to change of H₂O₂ in rat pulmonary artery smooth muscle cells (PASMCs) and to unbalance between cell proliferation and apoptosis of PASMCs induced by hypoxia.METHODS: The rat PASMCs were isolated from fresh normal lung tissues and cultured,which were divided into 6 groups,as follows: ① control group;② diazoxide group;③ 5-HD group;④chronic hypoxia group;⑤ chronic hypoxia+diazoxide group;⑥ chronic hypoxia +5-HD group.The relative change in mitochondrial potential was detected with rhodamine fluorescence (R-123) technique.The level of H₂O₂ in rat PASMCs was detected with chemiluminescence method.The proliferation of rat PASMCs was examined by cell cycle analysis and MTT colorimetric assay.RESULTS: After exposed to diazoxide for 24 h,the intensity of R-123 fluorescence,the level of H₂O₂ and the A value in normoxic rat PASMCs were significantly increased,and the apoptosis of rat PASMCs was significantly decreased as compared with control group (P<0.05).However,there were no significant changes in these tests after the rat PASMCs had been exposed to 5-HD for 24 h.Chronic hypoxia or chronic hypoxia+diazoxide markedly increased the intensity of R-123 fluorescence,the level of H₂O₂ and the A value in rat PASMCs,and also markedly decreased the apoptosis of rat PASMCs as compared with control group (P<0.05),and these changes were more significant in chronic hypoxia +diazoxide group than those in chronic hypoxia group (P<0.05).5-HD partly weakened the effect of hypoxia on the intensity of R-123 fluorescence,the level of H₂O₂,the A value and the apoptosis of rat PASMCs (P<0.05).Significant and positive correlations were found between the intracellular H₂O₂ and the R-123 fluorescence or the A value.Significant and negative correlation was found between the intracellular H₂O₂ and the apoptosis of rat PASMCs.CONCLUSION: The results suggest that the opening of MitoK_ATP followed by a depolarization of ΔΨm can contribute to the increase in the level of H₂O₂ in rat PASMCs and to the proliferation of rat PASMCs induced by hypoxia.This might be a mechanism of the development of hypoxic pulmonary hypertension.     

Effects of iPSC-MSCs on mitochondria of PC12 cells injured by CoCl2

AIM: To investigate the effects of induced pluripotent stem cells-derived mesenchymal stem cells (iPSC-MSCs) on cobalt chloride (CoCl₂)-induced injuries of PC12 cells and its possible mechanism. METHODS: PC12 cells were exposed to CoCl₂ to set up a chemical-induced cellular injury model and were cocultured with iPSC-MSCs. The cell viability was tested by CCK-8 assay. The apoptosis was measured by flow cytometry using Annexin V/PI staining. The mitochondrial membrane potential (MMP) was analyzed by flow cytometry using JC-1 staining. Immunofluorescence was employed to observe mitochondrial transfer from iPSC-MSCs to PC12 cells. RESULTS: Apoptosis of PC12 cells was increased and MMP of PC12 cells was decreased after exposed to CoCl₂ at concentration of 400 μmol/L for 24 h. Coculture of PC12 cells with iPSC-MSCs reduced the apoptosis and recovered the MMP of the PC12 cells. Tunneling nanotubes were formed between iPSC-MSCs and PC12 cells, through which the iPSC-MSCs transferred the mitochondria to the PC12 cells. CONCLUSION: iPSC-MSCs protect PC12 cells from CoCl₂-induced injuries, which may be associated with the mitochondrial transfer from iPSC-MSCs to PC12 cells.     

Effects of schisandrin B on apoptosis of lens epithelial cells treated with H2O2

AIM: To investigate the effects of Schisandrin B (Sch B) on apoptosis of lens epithelial cells (LEC) treated with H₂O₂. METHODS: Eyes in SDrats were excised and lenses were separated under operating microscope in sterilized condition. Lenses were divided randomly into four groups with different treatment: control group, hydrogen peroxide group (H₂O₂), pirenoxine sodium group (PS) and schisandrin Bgroup (Sch B). Lenses were incubated in CO₂ incubator for 24 h with 300 μmol·L^-1 H₂O₂ and with or without 0.5 mmol·L^-1 Sch B. LECaoptosis and apoptosis rate were measured by TUNELmethod. Ultrastructure changes and apoptosis bodies of LECwere observed via transmitted electron microscope. RESULTS: (1) Apoptosis rate in H₂O₂ group (92.0±2.6) was significantly higher than that in control group (3.5±1.8). Apoptosis rate in Sch Bgroup (13.8±3.27) was remarkably lower than that in H₂O₂ group and PSgroup. (2) Ultrastructure observation indicated that apoptosis cells occurred in most LEC in H₂O₂ group and the changes were severe presenting different stages. While a few apoptosis cells were observed in Sch Bgroup, the changes were slight and most of them were in early and middle stages. CONCLUSION: These data indicated that Sch Bsignificantly inhibited apoptosis of LECduring experimental oxidative injury, the effects were stronger than PS.     

Minocycline suppresses sodium nitroprusside-induced apoptosis in PC12 cells by regulating PI3K/Akt signaling

AIM：To explore the role of PI3K/Akt signaling in the anti-apoptotic effect of minocyline (MC) on the apoptosis of PC12 cells induced by sodium nitroprusside (SNP). METHODS：PC12 cells were divided into 4 groups: blank control group, SNP (500 μmol/L) group, MC (10 μmol/L)+SNP group and LY294002+MC+SNP group. The cell viability was observed by MTT assay. The expression of Akt and p-Akt was determined by Western blotting. RESULTS： The viability of the PC12 cells decreased after exposed to 500 μmol/L SNP for 24 h. Meanwhile, MC at concentration of 10 μmol/L significantly blocked the effect of SNP, such as decreasing the cell viability. Pretreatment with LY294002 for 60 min prior to exposure of the PC12 cells to MC and SNP down-regulated the expression of p-Akt induced by SNP. CONCLUSION：Minocycline regulates PI3K/Akt signaling pathway to restrain the apoptosis of PC12 cells induced by SNP.     

Ferulic acid protects against apoptosis of PC12 cells induced by kainic acid

AIM：To investigate the effect of ferulic acid (FA) on the apoptosis of PC12 cells induced by kainic acid (KA) in vitro. METHODS：In order to establish an Alzheimer disease neuronal cell model, the rat pheochromocytoma cell line PC12 was treated with KA at a concentration of 50 μmol/L. These model neurons were divided into KA model group and 3 groups treated with FA at doses of 25, 50 and 100 μmol/L, respectively. At the same time, normal group was established without KA pretreatment. The viability of the PC12 cells was detected by MTT assay. The expression of Bcl-2, Bax and cytochrome C (Cyt C) was determined by immunocytochemical method. Apoptotic rate of the PC12 cells was measured by flow cytometry with annexin V/PI double staining. The protein levels of Bcl-2, Bax and Cyt C were analyzed by Western blotting. RESULTS：The cell survival rate, the expression of Bcl-2 and the ratio of Bcl-2 to Bax in KA model group were significantly decreased (P<0.01),while the expression of Bax and Cyt C was obviously increased compared with normal control group (P<0.01). The apoptotic rate in KA model group was obviously increased compared with normal control group (P<0.01) After the intervention of FA, the cell survival rates were increased and the apoptotic rates were decreased. Furthermore, the positive rate and expression of Bcl-2, and the ratio of Bcl-2 to Bax in each dose of FA treatment group were significantly increased, while the expression of Bax and Cyt C in each dose group was significantly reduced as compared with KA model group (P<0.05 or P<0.01). CONCLUSION：KA obviously induces apoptosis of PC12 cells. FA had obvious protective effect on PC12 cells against the toxicity of KA. FA blocks endogenous apoptic pathway through inhibiting the expression of Bax and Cyt C and increasing the expression of Bcl-2 and the ratio of Bcl-2/Bax, thus improving the survival rate of PC12 cells.     

H2S inhibits neuron apoptosis induced by anoxia-reoxygenation through cAMP-mediated PI3-K/Akt/P70S6K kinase cell-survival signaling pathways

AIM: To investigate the effect of hydrogen sulfide on neuron apoptosis through PI₃-K/Akt/P70S6K cell-survival signal transduction pathways after neuron anoxia-reoxygenation.METHODS: Newborn (24-48 h) Wistar rats were decapitated.The hippocampus tissue was dissected and cells were suspended.Cells were plated at 1.0×10⁸ cells/L on poly-dlysine-treated 96-well (100 μL/well) plates and 6-well (2 mL/well) plates.Cells were used after 7 days.For anoxia-reoxygenation (oxygen glucose deprivation,OGD) experiments,cells were washed three times in a glucose-free balanced salt solution (BSS).They were then placed in deoxygenated glucose-free medium and cultured under 95% N₂,5% CO₂ in an anaerobic chamber equilibrated to 37 ℃ and 100% humidity for 45 min.OGD was terminated by replacement of stored medium and by returning the cultures to a standard incubator maintained at 37 ℃ in 95% air,5% CO₂.In experimental group,cells were respectively carried out OGD,OGD+150 μmol/L NaHS,OGD+150 μmol/L NaHS+10 μmol/L triciribin,OGD+150 μmol/L NaHS+10 nmol/L rapamycin and OGD+150 μmol/L NaHS+10 μmol/L triciribin+10 nmol/L rapamycin.Control cells were cultured normally.24 h later,neuron viability and apoptosis were measured.The level of cAMP and protein expression of PI₃-K,Akt and P70S6K were detected.RESULTS: NaHS enhanced concentration of cAMP and expression of PI₃-K,Akt and P70S6K.Meanwhile,increased neuron viability and decreased neuron apoptosis (P<0.01 vs group C or group I/R) were observed.Triciribin inhibited Akt and P70S6K,as well as increased neuron apoptosis and decreased neuron viability (P<0.05,P<0.01 vs group NaHS).Rapamycin inhibited P70S6K,as well as increased neuron apoptosis and decreased neuron viability (P<0.05,P<0.01 vs group NaHS).CONCLUSION: H₂S inhibits hippocampus neuron apoptosis and protects neuron from anoxia-reoxygenation injury through cAMP-mediated PI₃-K/Akt/P70S6K kinase cell-survival signaling pathways.     

Inhibitory effect of quercetin on apoptosis of PC12 cells induced by rotenone

AIM: To observe the effects and mechanisms of quercetin on the apoptosis of PC12 cells induced by rotenone. METHODS: PC12 cells were used in the study. Quercetin at the concentration of 300 μmol/L was added into the PC12 cells cultured in DMEM-F12 medium with 10% fetal calf serum. The morphological changes of the cells were observed under fluorescence microscope. The apoptotic rate was determined by flow cytometry assay. The protein levels of Bax and Bcl-2 were determined by Western blotting, and the mitochondrial membrane potential was measured by ratiometric probe JC-1.RESULTS: In the cells treated with rotenone+quercetin, the morphology of the cells was significantly improved, and the apoptotic rate was decreased to 6.7%, significantly lower than that in the cells treated with rotenone alone (P<0.01). The expression of Bcl-2 was up-regulated and Bax was down-regulated in rotenone+quercetin group (P<0.01), while the mitochondrial membrane potential was also increased (P<0.01) as compared to those in rotenone group.CONCLUSION: Pretreatment of quercetin inhibits the development of apoptosis in PC12 cells induced by rotenone. One of the mechanisms may be correlated with up-regulating the expression of Bcl-2 and down-regulating the expression of Bax, thus maintaining mitochondrial membrane potential.     

EGCG antagonizes hypoxia-induced autophagy and apoptosis in PC12 cells by mTOR regulation

AIM:Hypoxia (evoked by CoCl2)-induced apoptosis and autophagy are emerging as crucial events in the etiopathology of many neurodegenerative diseases. Epigallocatechin gallate (EGCG) is the active ingredient in tea polyphenols with abilities of anti-apoptosis and anti-autophagy, but the mechanism has not been fully elucidated. In recent years, studies have reported that the mammalian target of rapamycin (mTOR) involved in the regulation of a variety of neurological like differentiation and maturation of nerve cells, anti-oxidative stress, etc. Therefore, we investigate that whether EGCG protects PC12 from hypoxia-induced apoptosis and autophagy by enhancing mTOR expression. METHODS:The expression of mTOR and beclin-1 were detected by Western blotting. The expression of caspase-3 was measured by ELISA. The cell viability was detected by CCK-8 assay. The LC-3 expression in nucelus was observed by immunofluorescence. RESULTS:Hypoxia induced apoptosis and autophagy in PC12 cells. EGCG antagonized hypoxia-induced apoptosis and autophagy by enhancing mTOR expression. Blocking the pathway of mTOR reversed the protective effect of EGCG on PC12 cells. CONCLUSION: EGCG antagonizes hypoxia-induced autophagy and apoptosis in PC12 cells by controlling mTOR regulation.