Inhibitory effect of fructose-1, 6-diphosphate on adriamycin-induced cardiomyocyte apoptosis in rats

AIM:To study the effect of fructose-1, 6-diphosphate (FDP) on adriamycin(ADM)-induced cardiomyocyte apoptosis in rats. METHODS:Twenty-four Wistar rats were randomly divided into three groups: control group, ADM treated group and FDP intervention group. The contents of malondialdehyde (MDA) and NO₂^-/NO₃^-, the activities of glutathione peroxidase (GPx) and superoxide dismutase (SOD) were determined by colorimetric method in myocardial tissue, and the cardiomyocyte apoptosis was detected by TUNEL method in myocardial tissue, and the expression of inducible nitric oxide synthase (iNOS) mRNA, Bcl-2 mRNA and Bax mRNA in myocardial tissue were detected by in situ hybridization. RESULTS:The contents of NO₂^-/NO₃^- and MDA in myocardial tissue, the expressive levels of iNOS mRNA and Bax mRNA in cardiomyocyes and its apoptotic amounts in FDP intervention group were significantly lower than those in ADM treated group (P＜0.01). However, the activities of SOD and GPx in myocardial tissue, the expressive level of Bcl-2 mRNA of cardiomyocytes in FDP intervention group were significantly higher than those in ADM treated group (P＜0.01). CONCLUSION:FDP antagonized the reduced expression of Bcl-2 mRNA and increased expression of Bax mRNA in myocardial tissue induced by ADM, and in turn inhibited ADM-induced cardiomyocyte apoptosis.     

Cardiomyocyte apoptosis and related gene expression after acute myocardial infarction in rats

AIM: To investigate cardiomyocyte apoptosis and the expression of caspase-3, Bcl-2 and Bax after acute myocardial infarction (AMI) in rats.METHODS: AMI model was established with the ligation of left coronary artery in 78 randomly selected female SD rats.Twenty-four hours after operation, 43 survivors were randomly divided into 48-hour and 4-week two groups according to the time points: MI 48 h (n=11) and MI4 weeks (n=13) groups, sham-operated rats (S, n=27) were also randomly selected and reassigned to S48 h (n=10) and S4 weeks (n=10) groups.Cardiomyocyte apoptosis was detected with in situ terminal deoxynucleotidyl transferase (TdT)-dUTP nick-end labeling (TUNEL staining) and DNA gel electrophoresis.Caspase-3, Bcl-2 expression and Bax expression were detected with immunohistochemistry and Western blotting analysis.RESULTS: Compared with sham-operated group, after AMI, systolic, diastolic, and mean arterial blood pressures (SBP, DBP, MAP), left ventricular systolic pressure (LVSP) and the maximum change rate of left ventricular pressure rise and fall (±dp/dt) were significantly decreased (P<0.05, P＜0.01), while left ventricular end diastolic pressure (LVEDP) was significantly increased (P<0.05) in MI 48 h group.All the above indices in MI 4 weeks group had the same change as that in MI48h group, with the LVEDP significantly higher (P<0.01), except for a non-significantly change in SBP, DBP and MAP (all P>0.05).In both MI 48 h and MI 4 weeks groups, myocyte apoptotic index was significantly increased in the infracted/scar, border and non-infarcted areas (P<0.05,P＜0.01) with caspase-3 and Bax expressions increased significantly (P<0.05, P＜0.01) in myocytes of the above three areas and Bcl-2 expression increased only in myocytes of the infracted area in MI 48 h group.Western blotting indicated that Bcl-2/Bax ratio was also decreased in MI 48 h subgroup.CONCLUSIONS: After AMI in rats, cardiomyocyte apoptosis happened in the infarction/scar, border and non-infarcted areas, with caspase-3 and Bax expression in myocytes increased, and with Bcl-2 expression increased in myocytes of infracted area and Bcl-2/Bax ratio decreased only early after AMI.     

Effects of norepinephrine preconditioning and ischemic preconditioning on apoptosis and Bcl-2, Bax expression in rat myocardial cells during myocardial ischemic reperfusion

AIM: To study the effects of norepinephrine preconditioning(NE-P) and ischemic preconditioning (IP)on apoptosis and Bcl-2, Bax expression in rat myocardial cells in myocardial ischemic reperfusion (I/R). METHODS: The model of rat ischemic-reperfusion was used to conduct NE-preconditioning. Apoptotic myocytes were detected with TUNEL. Bcl-2, Bax expression were detected with immunohistochemistry. RESULTS: The rate of apoptosis cells in I/R group was higher, the rate of apoptosis cells in NE-P group and IP was lower significantly than that in I/R group(P＜0.01). The expression of Bcl-2 in I/R group was lower, but the expression of Bax was higher, the expression of Bcl-2 in NE-P group was higher significantly than that in I/R group(P＜0.01), the expression of Bax in NE-P group was lower than that in I/R group(P＜0.01). There was no significantly difference between NE-P and IP group in the above parameters (P＞0.05). CONCLUSION: NE-P reduced myocyte apoptosis by I/R in rats; The expression of Bcl-2 ,Bax genes played an important role in myocardial apoptosis.     

Effect of aminoguanidine on TNF-α,IL-1β and neuronal apoptosis after focal cerebral ischemic injury in rats

AIM: To evaluate the effect of aminoguanidine (AG) on inflammatory factors and neuronal apoptosis after focal cerebral ischemic injury in rats and the possible mechanism of protective effect of AG against cerebral ischemic injury.METHODS: Thirty male SD rats (weighing 250 g-280 g) were randomly divided into three groups: (1) sham operated group (SH group,n=10),(2) ischemic groups (IS group,n=10),(3) AG group (n=10).In AG group,AG at dose of 100 mg·kg-1 was given intraperitoneally twice a day for 3 consecutive days.In IS group,normal saline was given instead of AG.Focal cerebral ischemia was produced by middle cerebral artery occlusion (MCAO) for 12 h.A nylon thread with rounded tip was inserted into left internal carotid artery cranially until resistance was felt.The distance from bifurcation of common carotid artery to the tip of the thread was about 18-19 mm.Focal cerebral ischemia was confirmed by left Horners syndrome and right side hemiplegia.In SH group,the carotid artery was exposed but no thread was inserted.The expression of tumor necrosis factor-α(TNF-α) was determined by immunochemistry and the content of interleulin-1β(IL-1β) was measured by radioimmunoassay.The expressions of Bcl-2 and Bax protein were detected by flow cytometry.RESULTS: The expression of TNF-α and the content of IL-1β were markedly increased after MCAO.Significantly increased DNA fragmentation,the indication of apoptosis,was detected after MCAO.The expression of TNF-α and the content of IL-1β were significantly lower in AG group than those in IS group.The percentage of apoptosis cells and expression of Bax protein were markedly lower in AG group than those in IS group but still significantly higher than those in SH group.The expression of Bcl-2 protein was markedly higher in AG group than that in IS group.No significant difference in the expression of Bcl-2 protein between IS and SH group was observed.CONCLUSION: AG inhibits the increase in the expression of TNF-α and the content of IL-1β,and protects neurons from apoptosis induced by focal cerebral ischemia through increasing the Bcl-2 protein expression and inhibiting the Bax protein expression.     

Effects of simvastatin on expression of Bcl-2 and Bax in myocardium of rats with renal ischemia-reperfusion injury

AIM: To observe the effect of simvastatin on myocardial tissue after renal ischemia-reperfusion injury and its mechanism. METHODS: A rat model of renal ischemia-reperfusion injury was prepared by clamping the bilateral renal arteries for 45 min. The rats (n=36) were randomly divided into sham operation group, renal ischemia-reperfusion (I/R) group and simvastatin group with 12 rats in each group. The content of serum creatinine (SCr), blood urea nitrogen (BUN) and myocardial tissue malondialdehyde (MDA), the myocardial activity of lactate dehydrogenase (LDH), creatine kinase (CK) and superoxide dismutase (SOD), and the myocardial protein expression of Bcl-2 and Bax were detected. RESULTS: Compared with sham operation group, the content of SCr, BUN and myocardial MDA, and the myocardial activity of LDH and CK in I/R group were significantly increased (P<0.05), and the activity of SOD was significantly decreased (P<0.05). Compared with I/R group, the content of SCr, BUN and myocardial MDA, and the myocardial activity of LDH and CK in simvastatin group were significantly decreased (P<0.05), while SOD activity was enhanced (P<0.05). The protein expression of Bcl-2 and Bax in sham operation group was less than that in I/R group (P<0.05), and the protein level of Bax in simvastatin group was significantly lower than that in I/R group (P<0.05), while the protein level of Bcl-2 was increased (P<0.05). CONCLUSION: Simvastatin has a protective effect on the myocardium of the rats with renal ischemia-reperfusion injury, and the protective mechanism may be related to the elimination of free radicals by simvastatin, increase in the protein expression of Bcl-2 and decrease in the protein expression of Bax.     

Endogenous basic fibroblst growth factor is a protective factor against myocardial ischemia/reperfusion injury of rats

AIM: To observe the role of exogenous and endogenous basic fibroblst growth factor (bFGF) on myocardial ischemia/reperfusion(I/R) injury of rats.METHODS:bFGF and bFGF antiserum were applied to rat isolated I/R heart. Myocardial function, coronary effluent volume,protein and myoglobin content as well as LDH activity in coronary effluent fluid, myocardial calcium, MDA and ATP concentration as well as PKC, MAPK activity were measured. RESULTS:Compared with control, myocardial function in I/R group significantly decreased. Protein, myoglobin content and LDH activity in coronary effluent liquid as well as myocardial MDA and calcium content increased, while myocardial ATP concentration decreased(all P＜0.01). Compared with I/R group, ±LV dp/dt_max in bFGF group increased by 43% and 26%, respectively. LVEDP decreased by 40%. HRr/HRi and B/A augmented by 42% and 20%, respectively. Protein and myoglobin content as well as LDH activity lowered by 29%,30％ (all P＜0.01) and 33％ (P＜0.05) respectively. Myocardial MDA and calcium content decreased by 44% and 35%, respectively, while myocardial ATP level as well as PKC and MAPK activity increased by 34%,41％ and 10% (all P＜0.01), respectively. In bFGF antiserum group, ±LV dp/dt_max were 35% and 38% lower than those in I/R group. LVEDP increased by 93%. HRr/HRi and B/A decreased by 36% and 45%, respectively. Protein and myoglobin content as well as LDH activity augmented by 54%,96％ (all P＜0.01) and 34％ (P＜0.05) respectively. Myocardial MDA and calcium content increased by 24% and 50%, respectively, while myocardial ATP level as well as PKC and MAPK activity lowered by 28%,21％ and 8% (all P＜0.01), respectively. CONCLUSION:Endogenous bFGF is a protective factor against myocardial ischemia/reperfusion injury of rats.     

Effects of human thioredoxin on pneumocyte apoptosis and Bcl-2/Bax expression in rats with lung ischemia/reperfusion injury

AIM: To explore the relationship between apoptosis in the lung tissues and lung ischemia/reperfusion injury, and to observe the effects of human thioredoxin (hTrx) on apoptosis in lung ischemia/reperfusion injury. METHODS: The single lung in situ ischemia/reperfusion animal model was used. Eighty four Wistar rats were randomly divided into control group (control), groups of ischemia for 1 h and reperfusion for different times (IR1h, IR3h, IR5h), and groups of IR+human thioredoxin treatment (IR1h +hTrx, IR3h +hTrx and IR5h +hTrx). Transmission electron microscope (TEM), terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and immunocytochemistry techniques were used to observe apoptosis, apoptosis signal-regulating kinase 1 (ASK1) and expression of Bcl-2 and Bax in various phases of lung ischemia/reperfusion. RESULTS: Cell apoptosis in lung tissues was significantly high, ASK1, Bcl-2 and Bax protein were up-regulated in lung tissues of lung ischemia/reperfusion injury as compared to control (all P<0.01). Compared to IR group, hTrx suppressed apoptosis as well as expression of ASK1 and Bax protein (P<0.01), Bcl-2 protein and the ratio of Bcl-2/Bax were up-regulated in lung tissues (all P<0.05 or P<0.01). There was a significant correlation between the expression of ASK1, Bax protein and cell apoptosis (r=0.775, r=0.814, respectively; all P<0.01). There was a negative correlation between cell apoptosis and Bcl-2/Bax protein (r=-0.275, P<0.05). CONCLUSION: Initiating cell apoptosis by the activation of Bcl-2/Bax system in lung tissues may contribute to the pathogenesis of lung ischemia/reperfusion injury. The protective effects of hTrx include suppressing the expression of ASK1, down-regulating the ratio of Bcl-2/Bax and blocking apoptosis in lung tissues in lung ischemia/ reperfusion injury.     

Tetramethylpyrazine combined with bone marrow mesenchymal stem cell transplantation inhibits neuronal apoptosis in rats with cerebral ischemia

ATM: To investigate the effects of tetramethylpyrazine (TMP) combined with bone marrow mesenchymal stem cells (BMSCs) on neuronal apoptosis, and Bcl-2 and Bax expression in rats with cerebral ischemia. METHODS: The BMSCs were isolated by the whole bone marrow adherent method and cultured, and those in the 3rd passage were used for tail-vein transplantation. The rats were subjected to right middle cerebral artery occlusion (MCAO) using suture method, and the rats except sham group were randomly divided into model group, BMSCs (1×10⁹ cells/L) group, TMP (40 mg/kg) group and combination (TMP+BMSCs) group with 12 rats in each group. Neurological function was evaluated by modified neurological severity scoring (mNSS) on 1 d, 7 d and 14 d after cerebral ischemia. Toluidine blue staining was performed to detect cerebral infarct volume, HE staining was used to observe brain histopathological change, neuronal apoptosis was observed by TUNEL staining, and the mRNA and protein expression of Bcl-2 and Bax was detected by real-time fluorescence quantitative PCR and Western blot at 14 d after cerebral ischemia. RESULTS: Compared with BMSCs group and TMP group, TMP combined with BMSCs significantly reduced the score of mNSS (P<0.01) and the infarct volume (P<0.01), alleviated the pathological damage in the peripheral area of cerebral ischemia, decreased the number of TUNEL positive cells (P<0.01), increased the expression of Bcl-2 and decreased the expression of Bax at mRNA and protein levels (P<0.01).CONCLUSION: Tetramethylpyrazine combined with transplantation of BMSCs improves the functional recovery, reduces the infarct volume, relieves the ischemic injury of the brain tissue, and attenuates neuronal apoptosis in the rats with cerebral ischemia. The mechanism may be related to regulating the expression of Bcl-2 and Bax.     

Effects of non-wounded ischemic preconditioning on ischemia-reperfusion injury in isolated rat hearts

AIM:To observe the protective effect of non-wounded ischemic preconditioning on ischemic/reperfusion injury in isolated rat hearts. METHODS: 25 male SD rats, weighting (250±30) g, were randomly divided into three groups: control group (C,n=8), anoxia/reoxygenation group (A,n=8) and non-wounded legs ischemic preconditioning group (N-WIP,n=9).Hearts were isolated from rats and perfused on a Langendorff apparatus with a normal Krebs-Henseleit buffer (saturation 95% O₂+5% CO₂) at a constant pressure (8.33 kPa) and temperature (37 ℃) in C group; Following 15 min equilibration, hearts were subjected to 15 min of global ischemia and 15 min reperfusion (37℃) in A group; Rats were subjected to non-wounded leg repeated-brief ischemic preconditioning, and then treated in procedure similar to A group in N-WIP group.The activities of superoxide dismutase (SOD) and Ca²⁺-Mg²⁺-ATPase, malondialdehyde (MDA) content of efflux from coronary vessel and myocardium, myocardium monophasic action potential and contractile force were measured before ischemia, 15 minutes after ischemia and 5, 15 minutes after reperfusion. RESULTS:Compared with A group, non-wounded legs ischemic preconditioning reduced the incidence of reperfusion arrhythmias (P＜0.05), decreased the content of MDA of myocardium (P＜0.01), enhanced the activities of SOD (P＜0.01) and stabilized myocardial membranous potential,the activity of Ca²⁺-Mg²⁺-ATPase and contractile function. CONCLUSION:These results indicate that non-wounded leg ischemic preconditioning has a protective effect on ischemia-reperfusion injury in isolated rat hearts. The mechanism may be related to the strength of antioxidation, the stability of Ca²⁺-Mg²⁺-ATPase activity and membranous structure in myocardium.     

Effect of epigallocatechin gallate on cardiomyocyte apoptosis induced by ischemia-reperfusion in rats

AIM: To observe the effects of epigallocatechin gallate (EGCG) on cardiomyocyte apoptosis induced by ischemia-reperfusion (IR) in rats. METHODS: The left anterior descending branch of coronary artery was ligated for 30 min and reperfused for 60 min to make a the myocardial ischemia-reperfusion model in rats. The experiment was divided into five groups: sham, ischemia/reperfusion (IR), EGCG (10 mg/kg and 20 mg/kg) and salvia miltiorrhizae (SM, 100 mg/kg) group. The apoptotic cardiomyocytes were detected by in situ end labeling method, and the expressions of Bcl-2 and Bax were shown through immunohistochemistry method. RESULTS: There was no apoptosis myocardial cell in sham operation group. The apoptosis index and expression of bax significantly increased, and bcl-2/bax reduced in IR group (P<0.01). In EGCG-treated group, however, the changes above were obviously alleviated (P<0.01). CONCLUSION: EGCG significantly inhibits cardiomyocyte apoptosis in ischemia-reperfusion rat hearts. The possible mechanism is to raise the ratio of Bcl-2/Bax proteins by increasing in the expression of bcl-2 gene and decreasing in the expression of bax gene.     

Effect of fucoidan on intestinal ischemia-reperfusion injury in rats

AIM:To investigate the effect and potential mechanism of fucoidan on intestinal ischemia-reperfusion (I/R) injury in rats. METHODS:Adult male Wistar rats were randomly divided into 3 groups:sham group, I/R group and Fucoidan+I/R group. Fucoidan at 160 mg/kg was intraperitoneally injected in rats of Fucoidan+I/R group 7 d prior to operation, and the equal volume of saline was intraperitoneally injected in rats of sham group and I/R group. The rats in I/R group and Fucoidan+I/R group underwent superior mesenteric artery occlusion for 1 h and then reperfusion for 2 h. Following reperfusion, the histomorphological changes of the ileum were examined by HE staining. The levels of diamine oxidase (DAO), D-lactic acid (D-LA), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-1β were detected in the blood samples, the levels of malondialdehyde (MDA) and glutathione (GSH), the activity of superoxide dismutase (SOD) and myeloperoxidase (MPO), and the protein levels of Bax, cleaved caspase-3 and Bcl-2 were analyzed in intestinal tissue samples. RESULTS:Compared with sham group and Fucoidan+I/R group, the serum levels of DAO, D-LA, TNF-α, IL-6 and IL-1β were significantly increased in I/R group (P<0.05), Chiu's score of intestinal tissue, MDA content, MPO activity, the levels of Bax and cleaved caspase-3 protein in the intestinal tissues were also significantly increased (P<0.05), while the tissue GSH content, SOD activity, and Bcl-2 protein levels were significantly decreased (P<0.05). CONCLUSION:Fucoidan attenuates intestinal tissue damage caused by I/R, which may be related to anti-oxidation, anti-inflammatory and anti-apoptotic effects.     

Protective effect of ischemic-preconditioning under the mild hypothermia against small intestine ischemia-reperfusion injury in rats

AIM: To investigate the protective effect of ischemic-preconditioning under the mild hypothermia against small intestine ischemia-reperfusion injury in rats and its mechanism. METHODS: Thirty-two rats were randomized into 4 groups (8 rats in each group): sham operated group (Sham), ischemia-reperfusion (I/R) group, ischemic-preconditioning (IP) group, mild hypothermia ischemic-preconditioning (MHIP) group. The wet/dry ratio, Ca²⁺-Mg²⁺-ATPase activity in intestine tissue, the malondialdehyde (MDA) content, activities of lactate dehydrogenase (LDH), superoxide dismutase (SOD) and total antioxdase (TAX) in blood were determined. Ultrastructure, Bcl-2 and Bax expression in intestinal mucosa tissue were also observed. RESULTS: After I/R, the intestinal tissue wet/dry ratio, the content of MDA, LDH activity, the optic density of Bcl-2 and Bax proteins were significantly higher in I/R group than those in sham group (P<0.01). The activities of Ca²⁺-Mg²⁺-ATPase, SOD, TAX were significantly lower in I/R group than those in sham group (P<0.01). The intestinal tissue wet/dry ratio, the content of MDA, LDH activity and the optic density of Bax protein were significantly lower in IP group than those in I/R group (P<0.01), and also lower in MHIP group than in IP group (P<0.05). The activities of Ca²⁺-Mg²⁺-ATPase, SOD, TAX and the optic density of Bcl-2 protein were significantly higher in IP group than in I/R group (P<0.01). CONCLUSION: MHIP can protect intestine against I/R injury in rats, which may be related to enhancing oxidation-resistance of intestine, inhibiting lipid peroxidation, upregulating the expression of Bcl-2 protein and downregulating the expression of Bax protein.     

Panax quinquefolium saponins protect rat myocardium from ischemia/reperfusion injury through attenuating excessive endoplasmic reticulum stress

AIM: To investigate whether excessive endoplasmic reticulum stress (ERS) is involved in the protective mechanism of Panax quinquefolium saponins (PQS) against ischemia/reperfusion (I/R) injury in rat myocardium. METHODS: The model of myocardial I/R injury in vivo was made by ligating the left anterior descending artery for 45 min followed by 24 h of reperfusion in SD rats. The hemodynamics and serum content of cardiac troponin T (cTnT) were measured. The myocardial infarct size was measured by Evans blue and 2, 3, 5-triphenyltetrazolium chloride (TTC) staining. Cardiomyocyte apoptosis was detected using in situ TDT-mediated dUTP nick end labeling (TUNEL). The protein levels of glucose-regulated protein 78 (GRP78), calreticulin (CRT), C/EBP homologous protein (CHOP), caspase-12, apoptosis-associated proteins Bax and Bcl-2 were determined by Western blotting. RESULTS: Compared with I/R group, the mean arterial pressure in PQR+IR group was decreased by 32.0%, and left ventricular±dp/dtmax was increased by 64.0% and 35.0%, respectively.The serum content of cTnT was decreased by 53.3%, the percentage of area of necrosis (AN)/area at risk (AAR) was reduced by 65.5% and the apoptosis rate was decreased by 54.9%.The myocardial pathological changes were improved. Bcl-2 protein expression was increased by 110.0% and that of Bax was decreased by 47.8%. CRT protein expression was decreased by 43.4 %, CHOP protein expression and the protein level of cleaved caspase-12 were decreased by 38.6% and 23.7% in PQS+I/R group. CONCLUSION: PQS alleviates I/R injury in myocardium by inhibition of excessive ERS.     

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.     

Expression of calcium sensing receptor during ischemia/reperfusion myocardial damage and relationship between CaSR and injury of myocardium

AIM: To investigate the expression of calcium sensing receptor(CaSR) during myocardial injury induced by ischemia/reperfusion and disclose the relationship between CaSR and myocardial ischemia/reperfusion. METHODS: The experimental model was established by the 30 min ligating and 1 h, 2 h, 4 h, 6 h reperfusing the left descending coronary artery (LAD) in rats. Wistar rats were randomly divided into 5 groups: sham group, ischemia/reperfusion 1 h, 2 h, 4 h, 6 h groups (I/R 1 h, 2 h, 4 h, 6 h group). CaSR mRNA expression was detected by RT-PCR. Left ventricular function was recorded. The levels of plasma lactate dehydrogenase (LDH), alondialdehyde (MDA) and superoxide dismutase (SOD) were measured. The change of ultrastructure in the ischemia/reperfusion myocardium of rats was observed by electron microscopy. RESULTS: LVSP,±dp/dtmax and SOD activity decreased gradually with the reperfusion time prolonged. LDH and MDA peaked at 2 h. The ultramicro-structural injury at the 1 h and 2 h was more serious than that at 4 h and 6 h. The expression of CaSR increased significantly after reperfusion of 1 h and 2 h, and decreased after 4 h and 6 h. CONCLUSION: The increased expression of CaSR mRNA and serious injure of myocardium were observed. CaSR may be associated with the myocardial ischemia/reperfusion injury.     

Effects of ligustrazine ferulate on myocardial apoptosis and apoptosis-related protein expression in rats with myocardial ischemia-reperfusion injury

AIM:To observe the effects of ligustrazine ferulate on the apoptosis of myocardial cells in rats with myocardial ischemia-reperfusion injury, and to explore its possible mechanism. METHODS:Sixty male SD rats were randomly divided into five groups: sham-operation group, ischemia-reperfusion group, ligustrazine (4 mg/kg) group, low-dose (4 mg/kg) ligustrazine ferulate group and high-dose (8 mg/kg) ligustrazine ferulate group. The rat myocardial ischemia-reperfusion model was established by 30 min of myocardial ischemia followed by 120 min of reperfusion. Drugs were administered to the rats by jugular vein injection 10 min before reperfusion. After the reperfusion was finished, the biochemical indicators in serum and the histological indexes in myocardium were detected. RESULTS: Compared with ischemia-reperfusion group, ligustrazine ferulate lowered the serum levels of creatine kinase MB form, lactate dehydrogenase, cardiac troponin I and malondialdehyde, elevated the activity of total superoxide dismutase in serum and the expression of Bcl-2 protein in myocardium, decreased the expression of Bax protein and myocardial apoptotic index, and increased the Bcl-2/Bax ratio (all P<0.01). All the indicators in ligustrazine ferulate groups were dose-dependently superior to those in ligustrazine group (P<0.05 or P<0.01). CONCLUSION: Ligustrazine ferulate protects rats against myocardial ischemia-reperfusion injury. Its anti-apoptotic effect may be related to up-regulation of Bcl-2 and down-regulation of Bax.     

Effects of benazepril on cardiac function,free oxygen radicals,sarcoplasmic reticulum Ca2+-ATPase following cardiac ischemia-reperfusion in spontaneously hypertensive rats

AIM: To investigate the effects of angiotensin converting enzyme inhibitor (ACEI), benazepril (B), on cardiac function , free oxygen radicals, sarcoplasmic reticulum(SR) Ca²⁺-ATPase following ischemia-reperfusion in sportaneously hypertensive rats (SHRs). METHODS: Thirty 10-week-old female SHRs were randomly assigned into two groups: group SHR was control; The animal in group SHR+B was given with 10 mg/kg of benazepril per day. Another 15 Wistar rats with the same age and sex were normal control (group Wistar). After 12 weeks of pretreatment, all rats in each group were subjected to 30 min of left anterior descending coronary artery occlusion and 30 min of reperfusion. Hemodynamic parameters, left heart-to-body weight ratio (LVW/BW), myocardial malondialdehyde (MDA) concentration, superoxide dismutase (SOD) activity, and SR Ca²⁺-ATPase activity were measured. RESULTS: Compared to group Wistar, the rats in group SHR had higher blood pressure, LVW/BW and myocardial MDA concentration, more serious left cardiac function injury and lower myocardial SOD activity and SR Ca²⁺-ATPase activity; group SHR+B had lower myocardial MDA concentration, higher myocardial SOD activity, but no difference in blood pressure, LVW/BW, the degree of left cardiac function injury and myocardial SR Ca²⁺-ATPase activity. CONCLUSION: Benazepril can attenuate ischemia-reperfusion-induced cardiac function injury by regression of left ventricular hypertrophy (LVH), improving SR Ca²⁺-ATPase activity and decreasing oxygen free radicals injury in SHRs.     

Effects of berberine and yohimbine on splenocyte apoptosis in septic mice

AIM: To observe the effects of berberine and yohimbine on splenocyte apoptosis in septic mice and underlying mechanisms. METHODS: The mice were subjected to cecal ligature and puncture (CLP). The drugs or vehicle were given intragastrically 2 h after the surgery according to the following 5 groups: sham, CLP, CLP+berberine, CLP+yohimbine, and CLP+berberine+yohimbine. The apoptosis of splenocytes stained by TUNEL was observed under laser scanning confocal microscope 20 h after CLP. The splenic lymphocytes were isolated and observed using flow cytometry. The activities of caspase-3, caspase-8 and caspase-9 in splenic lymphocytes were detected, and the expression of Fas, Bim, Bcl-2 and Bax in the splenocytes was also determined by Western blotting. RESULTS: The TUNEL staining showed that the apoptotic rate of the splenocytes in septic mice 20 h after CLP was significantly higher than that in sham and CLP+yohimbine groups (P＜0.05). Compared with CLP group, the proportion of apoptotic cells was decreased in septic mice in CLP+berberine+yohimbine and CLP+yohimbine groups (P＜0.05). Flow cytometry analysis demonstrated the similar results in the apoptosis of splenocytes and T lymphocytes. However, only yohimbine treatment reduced the apoptosis of B lymphocytes in the spleen of sepsis-challenged mice. Compared with CLP group, caspase-9 activity was significantly reduced in CLP+berberine group (P＜0.05), the activities of caspase-3, caspase-8 and caspase-9 were all statistically reduced (P＜0.05) in CLP+yohimbine group and CLP+yohimbine+berberine group. CLP significantly increased the expression of cytosolic Fas, Bim and mitochondrial Bax in the splenocytes, and decreased Bcl-2 expression compared with sham group. Compared with CLP group, the expression of cytosolic Bim and mitochondrial Bax in CLP+berberine group were reduced (P＜0.05). Fas expression decreased only in CLP+yohimbine group (P＜0.05). Berberine combined with yohimbine reduced the expression of cytosolic Fas, Bim and mitochondrial Bax in the septic mouse splenocytes (P＜0.05).CONCLUSION: Yohimbine reduces sepsis-induced splenic lymphocyte apoptosis in mice by inhibiting Fas expression and in turn blocking both extrinsic and intrinsic apoptosis pathways. Berberine reduces Bim expression and inhibits caspase-9 activation, but not caspase-3 activation and apoptosis in the septic mouse splenocytes. Berberine combined with yohimbine reduces splenocyte apoptosis in the septic mice by inhibiting both extrinsic and intrinsic apoptotic pathways.     

Protective effect of heat-shock pretreatment on rat ischemia-reperfusion myocardium

AIM:To investigate the changes of expression of P-selectin (Ps) in ischemia-reperfusion myocardium and to observe the effects of heat shock protein (HSP) on the expression of Ps and apoptosis. METHODS:Mature female Wistar rats (n=40) were divided into three groups at random. Under general anesthesia, the rats in heat-shock group were subjected to whole-body hyperthermia, and those in the other two groups were treated with anesthetic alone. Twenty-four hours later, the animals in heat-shock group and in control group were subjected to surgical operative ligation of coronary left anterior descending branch (LAD) for 1 h, then accepted reperfusion for 2 h. Those in sham operation group were also performed surgical operation without LAD ligation for 3 h. After operation, the CK-MB in blood serum, infarct size of left ventricles, HSP70, Bax, Bcl-2, Ps and apoptosis cells were measured. RESULTS:The amount of HSP70 in heat-shock group was significant higher than that in control group and in sham operation group (P<0.05). There was no difference between control group and sham operation group (P>0.05). Compared with control group, the infarct size, CK-MB, apoptosis cells, Bax and Ps in heat-shock group were significantly reduced (P<0.05). However, expression of Bcl-2 was similar (P>0.05). No expression of Ps in sham operation group was detected. CONCLUSIONS:HSP70 may reduce myocardial apoptosis during ischemia-reperfusion. One of the mechanisms is that HSP70 restraines the expression of Bax and Bax/Bcl-2. Ps plays an injurious role in ischemia-reperfusion myocardium. HSP70 is likely to restrain Ps from expression, which may be one of the mechanisms by which heat-shock pretreatment plays a protective role in ischemia- reperfusion myocardium.     

Effects of bFGF on neuronal apoptosis and fractalkine expression in cerebral ischemia/reperfusion rats

AIM: To study the effects of basic fibroblast growth factor (bFGF) on neuronal apoptosis and fractalkine expression in ischemic penumbra after cerebral ischemia/reperfusion in rats.METHODS: Thirty-six rats were randomly divided into 3 groups: sham operation group, ischemia/reperfusion group and bFGF group. The model of middle cerebral artery occlusion was established by the method of intraluminal filament blockage. The middle cerebral arteries were blocked for 1 h and then reperfused for 24 h. Neurological performances of all rats were scored with Bederson's standard. The brain tissues of the rats were stained and the average infarct volume was calculated. TUNEL method was used to determine the number of apoptotic neurons, and the expression of fractalkine was detected by the method of immunohistochemistry.RESULTS: The score of neurological performances in bFGF group was 2.23±0.59, lower than that in ischemia/reperfusion group (3.18±0.65). The number of apoptotic neurons in bFGF group (13.22±1.35) was lower than that in ischemia/reperfusion group (17.28±1.01, P<0.05), which was the lowest in sham operation group (0.91±0.65). Compared with sham operation group, the expression of fractalkine in ischemia/reperfusion group was decreased. The expression of fractalkine in bFGF group was mainly higher than that in ischemia/reperfusion group (P<0.05).CONCLUSION: Up-regulation of fractalkine may be one of the molecular mechanisms of bFGF to protect neurons against ischemia/reperfusion injury.