蛋白激酶C与钙敏感受体在心肌缺血预适应中的保护作用

目的 探讨蛋白激酶C(PKC)与钙敏感受体(CaR),在心肌缺血预适应(IPC)中的保护作用.方法 采用细胞培养方法 ,体外培养大鼠乳鼠心肌细胞,模拟缺血预适应模型,实验分为7组:①正常对照组(C),②缺血再灌注组(1/R),③IPC组,④IPC+PKC抑制剂组(IPC+PKCI),⑤IPC+PKCI+CaR激动剂组(IPC+PKCI+CARS),⑥IPC+CaRS组,⑦IPC+CaR抑制剂组(IPC+CaRI).分别用TUNEL,Hoechst 33342染色法检测细胞凋亡,四甲基偶氮唑比色法(MTT)观察细胞存活率,Western Blot法检测胞浆内caspase-12,CaR,钙蛋白酶(calpain)表达.结果 光镜下,I/R组细胞核缩小,呈强蓝色荧光,染色质浓缩,出现凋亡小体,其他各实验组有不同程度的荧光增强,尤以IPC+PKCI+CaRS组多见强蓝色荧光细胞核.心肌细胞存活率和凋亡率,I/R组[(62.99±0.65)%,(19.13±0.87)%],IPC组[(78.67±0.37)%,(14.21±0.74)%],IPC+PKCI组[(71.09±0.52)%.(20.46±0.81)%],IPC+PKCI+CaRS组[(66.10±0.75)%,(24.89±1.43)%],IPC+CaRS组[(69.56±0.44)%,(21.64±0.77)%],IPC+CaRI组[(85.81±0.60)%,(13.12±0.69)%]明显低于或高于对照组[(100.00)%,(6.02±0.31)%],除IPC+CaRI组心肌细胞存活率外,其他各组与对照组比较差异有统计学意义(P＜0.05或＜0.01).Western Blot测定,胞浆白CaR蛋白在IPC+PKCI,IPC+CaRS,IPC+PKCI+CaRS组表达较IPC组高,IPC+CaRI组较IPC组低,caspase-12蛋白在I/R,IPC+CaRS,IPC+PKCI+CaRS 组,相对分子质量(胁)为60×103的活性片段表达均较高,calpain在I/R,IPC,IPC+PKCI,IPC+PKCI+CaRS,IPC+CaRS组表达均高于对照组和IPC+CaRI组,其中I/R组最高,对照组最低,IPC+CaRI组次之.结论 PKC与CaR受体之间的相互作用在IPC中可以通过减少肌浆网钙释放而起到对心肌的保护作用.Protective mechanism of the interaction between protein kinase C and calcium sensing receptor in jschemiapreconditioning DU Li-juan,WANG Yah-li,SUN Zhi-rui,ZHAO Ya-jun,LI Quan-feng,WANG Li-na,ZHANG Wei-hua Departmem of Pothophysioloty,Harbin Medical University,Harbin 150081,China

Protective mechanism of the interaction between protein kinase C and calcium sensing receptor in jschemiapreconditioning

Objective To investigate the protective mechanism of protein kinase C(PKC)and calcium sensing receptor(CaR)in ischemia preconditioned rat hearts.Methods Using cell culture method,in vitro cultured inhibitor(IPC+CaRI).Apoptosis was detected using TUNEL and Hoechst33342 cell viability was detected by MTT,the protein expression of easpase-12,calpain and CaR in endochylema were detected using Wedtetm blot.ResultsIn I/R group nucleus was shrank,big blue,chromatin concentrated,apoptotle body appeared.Other groups haddifferent fluorescence intensity varying degree,IPC+PKCI+CaRS group had more big blue nucleus.Myocardialcell viability and apoptotic rate,I/R group[(62.99±0.65)%,(19.13±0.87)%],IPC group[(78.67±0.37)%,(14.21±0.74)%],IPC+PKCI group[(71.09±0.52)%,(20.46±0.81)%],IPC+PKCI+CaRS group(66.10±0.75)%,(24.89±1.43)%],IPC+CaRS group[(69.56±0.44)%,(21.64±0.77)%],IPC+CaRI group(85.81±0.60)%,(13.12±0.69)%],all had a difference(P＜0.05 or＜0.01)compared with C group[(100.00)%,(6.02±0. 31)%].Western blot identified that CaR expression in IPC+PKCI and IPC+CaRS,IPC+PKCI+CaRS groupswas more than that in IPC and IPC+CaRI groups;easpase-12 had more active fragment(60×103)in I/R,IPC+CaRS,IPC+PKCI+CaRS groups;ealpain expressions in I/R,IPC,IPC+PKCI,IPC+PKCI+CaRS,IPC+CaRSgroups were higher than those in C and IPC+CaRI,I/R group was the highest one,C group the second,IPC+CaRI the third.Conclusion The interaction of PKC and CaR can reduce the intracellular Ca2+ from sarcoplasmicreticulum thus provide a protection.