Effects of fructose-1,6-diphosphate on adriamycin-induced calcium and sarcoplosnic reticulum Ca2+-ATPase activity in cardiomyocytes of rats

AIM: To study the effects of fructose-1,6-diphosphate (FDP) on adriamycin (ADR)-induced calcium and sarcoplasmic reticulum Ca²⁺-ATPase activity in cardiomyocytes of rats. METHODS: Rats were treated with ADR by intraperitoneal injection (2.5 mg·kg^-1 body weight) once every two days for 11 days, and then ADR-treated rats were intervened by FDP at different dosages (ip) once every other day for 41 days. Enzyme linked immune absorption assay (ELISA) was employed to detect froponin I (CTnI). CK-MB was examined by monoclonal antibody. Intracellular free calcium concentration was measured on fluorescent spectrophotometry and SRCa²⁺-ATPase activity was examined by inorganic phosphate. RESULTS: FDP (300, 600, 1 200 mg·kg^-1) significantly reduced the levels of CTnI and CK-MB in serum. Decreased calcium and increased SRCa²⁺-ATPase activity in cardiomyocytes were also observed when ADR-treated rats were intervened by FDP (P＜0.01). CONCLUSION: FDP reduced the injury of cardiotoxicity induced by ADR via decreasing intracellular free calcium and increasing SRCa²⁺-ATPase activity in cardiomyocytes.     

Effects of ischemic preconditioning on cardiac myocyte apoptosis and expression of bcl-2 during myocardial ischemia/reperfusion in rats

AIM:To explore the effect of ischemic preconditioning on cardiac myocyte apoptosis and the expression of bcl-2 during myocardial ischemia/reperfusion in rats. METHODS:We use TUNEL,immunohistochemical and in situ hybridization(ISH) methods to detect the cardiac myocyte apoptosis and the expression of bcl-2 during myocardial ischemia/reperfusion in rats. RESULTS:①The numbers of positive cardiac myocyte nuclear and the percentage of positive cardiac myocyte nuclear in IP+I/R_3h group decreased significantly(P<0.05,P<0.01)compared with I/R_3h group,respectively.②The numbers of bcl-2 protein positive cardiomyocyte and the percentage of bcl-2 protein positive cardiomyocyte in IP+I/R_3h group were higher(P<0.01)than that of I/R_3h group,respectively.The numbers of positive bcl-2 mRNA cardiomyocyte and the percentage of positive bcl-2 mRNA cardiomyocyte in IP+I/R_1h group were higher(P<0.01)than that of I/R_1h group,respectively.CONCLUSION:① The first window of IP's protection could reduce cardiomyocyte apoptosis significantly.② Up-regulating the protein expression of bcl-2 in cardiomyocytes during I/R may be one of the mechanisms of first window of IP's protection.     

苹果miR396家族鉴定及在不定根发育过程中的表达分析

分析了苹果miR396家族进化特性及其在苹果不定根发育过程中的表达模式。结果表明:苹果miR396家族有4条成熟体和7条前体序列(pre-miRNA)。Mfold预测显示Pre-miR396家族7个成员序列均可形成典型稳定的茎环二级结构,最小折叠自由能介于–62.9 kal·mol^-1(pre-miR396b)～–51.9kal·mol^-1(pre-miR396g)之间。系统发育进化树分析显示,pre-miR396家族亲缘关系可分为3个亚组(G1、G2、G3),每个亚组内基因数量不同,分别含有11、9、19个。靶基因预测显示,苹果miR396靶基因包括MdGRF1、MdGRF2和MdGRF5等,降解组测序进一步验证了mi R396对其候选靶基因MdGRF1、MdGRF2和MdGRF5的剪切关系。苹果miR396家族成员在侧根和果实中的表达量显著高于其他组织,其候选靶基因表达量则在花芽和腋芽中显著高于其他组织;不定根发育过程中,miR396家族不同成员表达模式存在显著差异,整体上呈上调表达趋势,其候选靶基因呈下调表达趋势;外源IBA处理显著诱导...     

Cardiomyocyte apoptosis and related genes expression in sinoaortic-denervated rats

AIM: To study apoptosis and related genes expressions of cardiomyocytes in sinoaortic-denervated(SAD) rats. METHODS: SAD or sham-operation (Sham) was performed in male SD rats at the age of 10 weeks. After 16 weeks, apoptotic cells were stained in situ by terminal dexynucleotidyl-transferase mediated-dUTP nick end labeling (TUNEL). All stained results were analysised using computer image analysis techniques. Protein products and mRNA of Bcl-2, Bax, Fas and Fas-L were assessed by quantitative immunohistochemistry and RT-PCR. RESULTS: The numbers of apoptotic cardiomyocytes were significantly increased in SAD rats, the expressions of Bcl-2 were significantly decreased, whereas Bax,Fas and Fas-L were significantly increased in SAD rats.CONCLUSION: Apoptosis and dysregulation of gene expressions may be involved in the cardiomyocytes remodeling in SAD rats.     

Time course and distribution of myocyte apoptosis induced by acute ischemia in rats

AIM:Myocyte apoptosis in rats can be induced by acute ischemia, but time course and distribution of myocyte apoptosis were unclear.METHODS:DNA agarose gel electrophoresis and TdT-mediated dUTP nick end-labling(TUNEL)assay were performed to evaluate apoptosis in mycardium exposed to 45 minutes, 2 hours, 6hours, 12 hours ischemia and sham-operated rats in vivo.RESULTS:DNA ladders were clearly visible in agarosegel of DNA from ischemic myocardium exposed to 2 hours, 6 hours and 12 hours ischemia, and DNA ladders became more apparent with increasing duration of ischemia.TUNEL positive cells with apoptotic morphologic characters were present in above ischemia time, and apoptotic index increased with increasing ischemia time.The majority of TUNEL positive cells were myocytes.Apoptotic index was higher in subendocardium than in subepicardium(P<0.101), while higher in border ischemia region than in the central ischemia area(P<0.105).CONCLUSION:A time-effect relation existed between the number of apoptosis and the time range of supposed time;Apoptotic myocytes scattered inthe ischemic myocardium, mainly localized at subendocardium and ischemic border.     

Inhibitory effect of geinistein on apoptosis in hUVECs induced by MCP-1

AIM: To study the inhibitory effect of genistein on apoptosis in human umbilical vein endothelial cells (hUVECs) induced by monocyte chemotactic protein-1 (MCP-1). METHODS: The hUVECs were cultured in vitro and identified. Growth-arrested hUVECs were stimulated with genistein at different concentrations (0.1 μmol, 1.0 μmol, 10 μmol, 100 μmol) and co-treated with MCP-1 (10 μg/L). The survival rates of hUVECs were detected by MTT assay. The cell cycle and DNA content were detected by flow cytometry. To explore the possible mechanism of the genistein interventions, the expressions of Bcl-2, Fas and Bax proteins were detected by flow cytometry and Western blotting.RESULTS: Genistein increased the survival rate and the level of Bcl-2, inhibited Fas and Bax, decreased the ratios of apoptosis compared with MCP-1-induced hUVECs apoptotic group in a dose-dependent-manner. CONCLUSION: Genistein inhibits the apoptosis induced by MCP-1 and the inhibitory effect was relative to the dose of genistein. Its mechanism might be involved in the down-regulation of Fas and Bax expressions and the up-regulation of Bcl-2.     

Role of thioredoxin-ASK1 in doxorubicin-induced apoptosis of neonatal rat cardiac myocytes

AIM: To investigate the role of thioredoxin(Trx)-apoptosis signal-regulating kinase 1(ASK1) in doxorubicin-induced apoptosis of neonatal rat cardiac myocytes (NRCMs). METHODS: Primary cardiomyocytes were isolated from newborn Sprague-Dawley rats with the purity of NRCMs >95%. NRCMs were pretreated with the indicated concentrations of ebselen 2 h prior to the addition of doxorubicin, then treated with doxorubicin at concentration of 1 μmol/L for another 24 h. The viability of the cells was examined by MTT assay.Reactive oxygen species(ROS) levels were measured by a ROS-specific probe 2',7'-dichlorodihydrofluorescein diacetate (H₂DCFDA). Apoptotic cardiomyocytes were determined by Hoechst 33258 nuclear staining. The activity of caspase-3 was detected with a caspase-3 colorimetric assay kit. The protein levels of poly(ADP-ribose) polymerase 1(PARP1), ASK1, p-ASK1, p38 and p-p38 were determined by Western blotting. Immunoprecipitation and immunoblotting were performed to detect whether the Trx-ASK1 was dissociated. RESULTS: Doxorubicin induced significant apoptosis of NRCMs. The levels of ROS were significantly increased. Ebselen significantly decreased the apoptosis. Compared with control group, increased activity of caspase-3 was showed in doxorubicin group (P<0.01). Increased protein levels of PARP1, ASK1 and p38 were observed (P<0.01). The increase in the dissociated Trx-ASK1 was also found. Compared with doxorubicin group, ebselen decreased the activity of caspase-3 (P<0.01), the levels of PARP1,ASK1 and p38 proteins (P<0.05), and the dissociated Trx-ASK1. CONCLUSION: Doxorubicin induces significant apoptosis of NRCMs. ASK1 is partly dissociated from Trx, and starts the ASK1-mediated apoptotic signaling. The process is significantly attenuated by pretreatment with ebselen. Trx-ASK1 plays an important role in doxorubicin-induced apoptosis of cardiomyocytes.     

Glucose-regulated protein 78 promote cardiomyocyte apoptosis in liver cirrhotic rats

AIM: To explore the cardiomyocyte apoptosis induced by glucose-regulated protein 78/immunoglobulin heavy chain-binding protein (GRP78/BiP) in liver cirrhotic rats and its mechanism. METHODS: The liver cirrhotic rat model was established with multiple pathogenic factors, and sampled at the time points of 4 weeks, 6 weeks and 8 weeks. In experiment 1, the heart was collected and weighed, the thickness of the left ventricular wall was measured, and the ratios of the left ventricular wall thickness to the heart weight, and the heart weight to the body weight were calculated. In experiment 2, TUNEL was used to detect the apoptotic cardiomyocytes,and the protein levels of GRP78/BiP, CCAAT/enhancer-binding protein homologous protein/growth arrest and DNA damage-inducible protein 153 (CHOP/GADD153), caspase-12, nuclear factor-κB p65 (NF-κB p65) and B-cell lymphoma/leukemia-2 (Bcl-2) in the myocar-dium were detected by the method of immunohistochemistry. RESULTS: Compared with the normal myocardium, significant larger ratios of the left ventricular wall thickness to the heart weight and the heart weight to the body weight, a significant increase in the cardiomyocyte apoptosis, and a significant larger positive expression index of GRP78/BiP in the hearts 8 weeks after modeling were observed. The protein levels of CHOP/GADD153 and caspase-12 were gradually increased during the development of liver cirrhosis and were significantly increased at 8 weeks. The positive expression of NF-κB p65 and Bcl-2 showed consistent changes, and were markedly higher at 4 weeks than those at the other time points. The positive expression index of GRP78/BiP was positively correlated with the apoptotic index, and the levels of CHOP/GADD153 and caspase-12. The positive expression index of CHOP/GADD153 was negatively correlated with NF-κB p65 and Bcl-2. CONCLUSION: Elevated expression of GRP78/BiP may play a crucial role in the pathogenesis of liver cirrhotic cardio-myopathy mediated by endoplasmic reticulum stress.     

Effect of PKC activition on cardiac myocyte apoptosis and Bcl- 2 expression during myocardial ischemia/reperfusion in rats

AIM: To explore the effect of PKC activition on cardiac myocyte apoptosis and expression of bcl- 2 during myocardial ischemia/reperfusion(I/R) in rats. METHODS: TUNEL,immunohistochemistry and in situ hybridization were used. RESULTS: The TUNEL data showed that the numbers of positive cardiac myocyte nucleus and the percentage of positive cardiac myocyte nucleus in PMA+IR_{3 h} group decreased significantly(P＜0.05,P＜0.01), compared to those in IR_3h group. The number of Bcl-2 protein positive cardiomyocytes and the percentage of Bcl-2 protein positive cardiomyocytes in PMA+IR_3h group were higher than those in IR_3h group (P＜0.01) bcl- 2 mRNA expression showed the same changes in PMA+IR_0h group compared to IR_1h group.CONCL USIONS:Activation of PKC decreased cardiomyocyte death during I/R.Upregulation of bcl-2 gene expression in cardiomyocytes during I/R may be one of the mechanisms of decreasing cardiomyocyte death by PCK activating during I/R.     

Relationship between apoptosis,proliferation and expression,mutation of related genes in breast cancer

AIM:To study the relationship between apoptosis, proliferation and expression,mutation of related genes in breast cancer.METHODS:Methods of TUNEL, immunohistochemical S-P and PCR-SSCP were used respectively to study apoptotic index (AI), mitotic index(MI), expression of Bcl-2,p53,c-erbB-2,PCNA,Ki67,TopoⅡ and mutation of p53 in 54 cases of breast cancer.RESULTS:AI and MI were 9.40±3.78 and 5.96±2.36, respectively. There was a significant direct correlation between them(r=0.46.P＜0.01).High expression of Bcl-2,PCNA,Ki67,TopoⅡ coincided with high AI,MI(P＜0.01). High expression of p53,c-erbB-2 and mutation of p53 coincided with high MI(P＜0.01). Type of p53 mutation coincided with AI(P＜0.05).CONCLUSION:Disturbance of gene control between apoptosis and proliferation is related with expression,mutation of related genes in breast cancer.     

Inhibitory effect of butylphthalide on apoptosis of hippocampal neurons in Alzheimer disease rats via SIRT1/NF-κB signaling pathway

AIM: To investigate the effect of butylphthalide on apoptosis of hippocampal neurons in Alzheimer disease (AD) rats via SIRT1/NF-κB signaling pathway and its mechanism. METHODS: AD rat model was established by intragastric administration of AlCl₃ and intraperitoneal injection of D-galactose. After treated with butylphthalide at 25 mg/kg (low dose), 50 mg/kg (medium dose) and 100 mg/kg (high dose), the effects of butylphthalide on the morphology of hippocampal neurons, apoptosis rate, and the protein levels of Bcl-2, Bax, cleaved caspase-3 and the SIRT1/NF-κB signaling pathway associated proteins were determined by HE staining, flow cytometry and Western blot, respectively. After treated with SIRT1 agonist SRT1720 and inhibitor sirtinol, the role of SIRT1/NF-κB signaling pathway in hippocampal neuronal apoptosis was observed. On the basis of giving 50 mg/kg butylphthalide, sirtinol was administered, and the effect of butylphthalide on neuronal apoptosis regulated by SIRT1/NF-κB signaling pathway was evaluated. RESULTS: The morphology of hippocampal neurons in the AD rats were improved, the apoptosis rate of hippocampal neurons and the protein levels of Bax and cleaved caspase-3 were inhibited, and the protein levels of Bcl-2 and the activation of SIRT1/NF-κB signaling pathway were promoted by butylphthalide significantly (P<0.05). The protein expression of Bcl-2 and the activation of SIRT1/NF-κB signaling pathway were promoted, and the apoptosis of hippocampal neurons and the protein levels of Bax and cleaved caspase-3 were inhibited by SRT1720 remarkably (P<0.05), whereas the effect of sirtinol was contrary to that of SRT1720. After sirtinol treatment, the inhibitory effect of butylphthalide on apoptosis of hippocampal neurons, the protein levels of Bax and cleaved caspase-3, and the promotion of Bcl-2 protein expression in hippocampal neurons were markedly weakened (P<0.05). CONCLUSION: Butylphthalide inhibits the apoptosis of hippocampal neurons in the AD rats by down-regulating the protein expression of Bax and cleaved caspase-3, and up-regulating the protein expression of Bcl-2 through activating SIRT1/NF-κB signaling pathway.     

Influence of energetic metabolism alteration on cardiac myocyte apoptosis

Many studies indicate that apoptosis is involved in the progression of congestive heart failure. At present, mechanisms that mitochondria regulates cell apoptosis is widely accepted.Cardiac myocytes have abundant mitochondria, which plays an important role in maintenance of cell physiological function. Recent studies find that cardiac energy metabolic shifts occur as a normal response to diverse physiologic and dietary conditions and as a component of the pathophysiologic processes which accompany cardiac hypertrophy, heart failure, and myocardial ischemia.Both clinical and experimental studies show that cardiac function can be improved and apoptosis is inhibited by intervention in energetic metabolism of myocytes.     

Protective effect of cardiomyopeptidin on cultured rat neonatal myocardial cells damaged by adriamycin

AIM:To investigate the protective effect of cardiomyopeptidin on cultured myocardial cells damaged by adriamycin in neonatal rats.METHODS:The activities of CPK, LDH and the dehydrogenase of mitochondria in the cells damaged by adriamycin were observed in the presence or absence of cardiomyopeptidin, _i was measured with fluorescent dye Fura-2-AM.RESULTS:Cardiomyopeptidin reduced the activities of CPK and LDH and increased the activities of dehydrogenase of mitochondria in a dose-dependent manner; CMP also dose-dependently decreased _i.CONCLUSION:Cardiomyopeptidin has a protective effect on cultured rat neonatal myocardial cells damaged by adriamycin.     

Role of CRIF1 in cardiomyocyte apoptosis induced by palmitic acid

AIM: To investigate the effects of CR6-interacting factor 1 (CRIF1) on the apoptosis of mouse cardiomyocytes (MCMs) induced by palmitic acid. METHODS: The MCMs cultured with medium containing palmitic acid at 0 and 300 μmol/L for 24 h were divided into control group and palmitic acid group, respectively. In order to explore the effects of CRIF1 on MCMs injuries induced by high fat, MCM exposed to palmitic acid at 300 μmol/L for 24 h were divided into vehicle group, scrambled (Scra) siRNA group and CRIF1 siRNA group. The cells in vehicle group were only treated with transfection reagent, the cells in Scra siRNA group were given a treatment with transfection reagent and scrambled RNA, and the cells in CRIF1 siRNA group were given a treatment with transfection reagent and CRIF1 specific siRNA. In order to further confirm the specific mechanism of CRIF1 in high fat-induced MCM injuries, MCMs in CRIF1 siRNA group were divided into DMSO group and N-acetyl cysteine (NAC) group, and were given the same intervention of palmitic acid. RT-qPCR, Western blot and immunofluorescence staining were used to detect the mRNA and protein expression of CRIF1. The apoptotic rate was analyzed by flow cytometry, and the level of intracellular reactive oxygen species (ROS) was tested by DHE staining and ELISA. RESULTS: The expression of CRIF1 was significantly increased after exposure to palmitic acid (P<0.05). Compared with control group, the apoptotic rate was increased significantly in vehicle group and Scra siRNA group (P<0.05). The apoptotic rate was significantly increased in CRIF1 siRNA group (P<0.05). Compared with control group, the intracellular ROS content was significantly increased in vehicle group and Scra siRNA group (P<0.05). Compared with vehicle group and Scra siRNA group, the intracellular ROS content was significantly increased in CRIF1 siRNA group (P<0.05). Compared with DMSO group, the intracellular ROS content and the apoptotic rate were remarkably decreased in NAC group (P<0.05). CONCLUSION: With the inhibition of oxidative stress, CRIF1 may reduce the apoptosis of MCMs induced by high fat.     

Inhibitory effect of salidroside on liver oxidative stress in rats with non-alcoholic steatohepatitis

AIM：To explore the effects of salidroside (SDS) on the oxidative stress in liver tissues from rats with non-alcoholic steatohepatitis (NASH). METHODS：The experimental animal model of NASH was established in SD rats fed on high-fat and high-cholesterol diet (HFHCD) for 14 weeks. SDS (300 mg·kg-1·d-1) was administered via gavage daily from the 8th week after HFHCD feeding. At the end of the 14th week, serum samples were taken for detection of alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG) and total cholesterol (TC). Liver tissues were taken for TG, TC, malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) detection. The content of 8-isoprostaglandin F2α (8-iso-PGF2α) in liver tissues was determined by ELISA. The liver histopathological changes were observed under microscope with HE staining. The expression of 8-hydroxydeoxyguanosine (8-OHdG) in liver tissues was determined by immunohistochemical staining. RESULTS：At the end of the 14th week, ALT, AST, TG and TC in serum, and TG, TC, MDA and 8-iso-PGF2α in liver homogenate in NASH model group were significantly increased compared with control group, while SOD and GSH in liver tissues were significantly decreased. The liver expression of 8-OHdG in NASH model group was higher than that in control group. Compared with NASH model group, SDS significantly inhibited the elevation of serum ALT, AST, TG and TC, and liver TG, TC, MDA and 8-iso-PGF2α, but increased the levels of SOD and GSH in liver tissues. Meanwhile, the liver histopathological score and 8-OHdG expression were decreased in SDS treatment group. CONCLUSION：Salidroside can effectively inhibit steatohepatitis induced by HFHCD, and its antioxidant effect may be one of the mechanisms.     

Effects of ischemic preconditioning on hepatocyte apoptosis induced by hepatic ischemia-reperfusion in cirrhotic rats

AIM:To investigate the protective effect of ischemic preconditioning (IPC) on hepatic ischemia-reperfusion(I/R) injury in cirrhotic rats and its possible mechanism. METHODS:Hepatic I/R was induced by Pringle maneuver. The cirrhotic rats were randomized into three groups: Group A: before 30 min of ischemia, a short period of 5 min ischemia and 5 min reperfusion were given; Group B: before 30 min of ischemia, a short period of 10 min ischemia and 10 min of reperfusion were given; Group C: 30 min ischemia only. The serum alanine transferase (ALT), hepatic Fas-mRNA, caspase-3 activity and hepatocyte apoptosis were analyzed. RESULTS:The 7-day survival rate in the group A and B were 100%, respectively. However, it was only 62.5% in the group C. After 6 h of reperfusion, the ALT levels in both group A and B were significantly lower than that of in group C, P＜0.01. The ALT level of group A was also lower than that of group B, P＜0.01. The hepatic Fas-mRNA expression, caspase-3 activity and apoptotic hepatocyte in group A were significantly lower than those of in group C, P＜0.01. CONCLUSIONS:IPC has significant protective effect against hepatic I/R injury. An IPC with 5 min of ischemia and 5 min of reperfusion has the maximal protective effect. The protective mechanism of IPC against hepatic I/R injury is via down-regulation of Fas-mRNA expression, inhibiting caspase-3 activity and subsequently inhibiting hepatocyte apoptosis.     

Protective effect of HSP70 on injuried myocardial cells induced by H2O2

AIM: To investigate the role of heat-shock protein 70(HSP₇₀) in the protection of myocardial cells against ischemic injury.METHODS: Myocardial cells were cultured in vitro. HSP₇₀ was induced by hyperthermia. H₂O₂-injured myocardial cells were divided into different groups. Flow cytometry, DNA Ladder and biochemistry methods were employed to observe the myocardial cells of different groups.RESULTS: Immunohistochemistry showed hyperthermia induced the up-regulation of HSP₇₀ in myocardial cells. Apoptotic rate, activity analysis of cytochrome C and succinic dehydrogenase in H₂O₂-injuried and HSP₇₀-protected groups were obviously different. Electron micrograph shomed hyperthermia alliviated myocardial cell injury induced by H₂O₂. CONCLUSION: HSP₇₀ delays apoptosis and protects against H₂O₂-induced myocardial cell injury.     

Effects of taurine on the change of apoptosis induced by IL-1β, TNF-α and IFN-γ in rat pancreatic islet cells

AIM: To investigate the changes of apoptosis in isolated pancreatic islet cells, insulin secretion, expression of Bcl-xL and Bax induced by combination of IL-1β, TNF-α and IFN-γ, and effects of taurine on them.METHODS: Isolated pancreatic islet cells from Wistar rat were incubated in monolayer in vitro. NO^-₂/ NO^-₃ production, NOS activity, insulin secretion, the protein expression of Bcl-xL and Bax, percentage of islet cell apoptosis and DNA fragmentation in pancreatic islet cells incubated with combination of IL-1β, TNF-α and IFN-γ were measured, and the effects of taurine on the changes of them were further investigated. RESULTS: Combination of IL-1β, TNF-α and IFN-γ induced a significant increase in percentage of pancreatic islet cell apoptosis, NO^-₂/ NO^-₃ production and NOS activity, DNA ladder appearance, a decrease in insulin content, up-regulation in the protein expression of Bax and down-regulation in the protein expression of Bcl-xL (P<0.01), which were blocked by addition of taurine (P<0.01). These effects occurred in a dose dependent manner.CONCLUSION: Taurine attenuates β cell apoptosis induced by IL-1β, TNF-α and IFN-γ. The mechanism of which may be the inhibition of NOS activity and the decrease of NO production as well as the downregulation of Bax/Bcl-xL proportion.     

Effects of Panax quinquefolium saponin on mitochondrial membrane potential and cardiomyocyte apoptosis in ischemia/reperfusion rats

AIM：To investigate whether mitochondrial membrane potential (ΔΨm) and the mitochondrial apoptotic pathway are involved in the protective mechanism of Panax quinquefolium saponin (PQS) against cardiomyocyte apoptosis after ischemia/reperfusion (I/R) injury in rat myocardium. METHODS：Ninety healthy male SD rats were randomly divided into sham group, I/R group, PQS (200 mg·kg-1·d-1) +I/R group, cyclosporine A (CsA) group, CsA (10 mg·kg-1) +I/R group and PQS +CsA +I/R group. The model of myocardial I/R injury in vivo was established by ligating the left anterior descending artery (LAD) for 30 min followed by 120 min of reperfusion in the rats. The serum activity of lactate dehydrogenase (LDH) was measured by automatic chemistry analyzer. The myocardial infarct size was measured by Evans blue and 2,3,5-triphenyltetrazolium chloride (TTC) staining. Cardiomyocyte apoptosis was detected by in situ TDT-mediated dUTP nick end labeling (TUNEL). The protein levels of Bcl-2, Bax, cleaved caspase-3 and cytosolic cytochrome C were determined by Western blotting. ΔΨm was measured by laser scanning confocal microscopy and fluorescence microplate reader. RESULTS：Compared with I/R group, the serum content of LDH,the infarction size in PQS+I/R group, CsA+I/R group and PQS+CsA+I/R group and the myocardial apoptotic index were decreased. Compared with I/R group, the fluorescence intensity of mitochondria after JC-1 staining was enhanced in PQS+I/R group, CsA+I/R group and PQS+CsA+I/R group, and the relative fluorescence units (RFU) of ΔΨm were improved in those 3 groups. In PQS+I/R group, CsA+I/R group and PQS+CsA+I/R group, the protein expression of Bcl-2 was increased, and that of Bax was decreased compared with I/R group. Moreover, in those 3 groups, the protein levels of cleaved-caspase-3 and cytosolic cytochrome C were decreased compared to I/R group, respectively. CONCLUSION：PQS attenuates myocardial injury and cardiomyocyte apoptosis during I/R, and the protective mechanisms of PQS were associated with the modulation of ΔΨm and the inhibition of mitochondrial apoptosis pathway.