HOE642对缺氧/复氧心肌细胞的保护机制

Protection of HOE642 Against Cardiomyocyte Injury Caused by Anoxia and Reoxygenation

目的观察Na+/H+交换抑制剂HOE642对心肌细胞缺氧/复氧(A/R)损伤的保护作用,方法原代培养的心肌细胞分为对照组、A/R组、A/R+HOE642组、A/R+尼卡地平(Nic)组、A/R+蛋白激酶(PKC)阻滞剂(H7)组和A/R+丝裂元活化蛋白激酶(MAPK)阻滞剂(PD98059)组。检测各组心肌细胞内游离钙浓度([Ca2+]i)、细胞活力、ATP含量及孵育液中乳酸脱氢酶(LDH)含量、MAPK和PKC活性。免疫印迹法检测心肌细胞钙蛋白酶(u-calpain和m-calpain)。结果A/R+Nic、A/R+HOE642使心肌细胞[Ca2+]i降低,且m-calpain蛋白表达亦降低。A/R+Nic、A/R+HOE642组心肌细胞孵育液中心肌激酶(LDH、CK)均低于A/R组(P<0.01);细胞活力、ATP含量、PKC和MAPK活性高于A/R组(P<0.05或P<0.01)。PKC抑制剂H7及MAPK抑制剂PD98059组心肌细胞孵育液中心肌激酶(LDH、CK)均高于A/R组(P<0.05),细胞活力、ATP含量明显低于A/R组(P<0.05)。结论HOE642与钙通道阻滞剂一样,可抑制心肌细胞内游离钙超载引起的心肌细胞A/R损伤,阻断PKC和MAPK,使A/R的心肌细胞损伤加剧。

Objective To investigate the protective effect of calcium antagonists on anoxia/reoxygenation （A/R） injury of cardiomyocytes. Methods Primary-cultured cardiomyocytes were divided into six groups, namely A/R, A/R ＋ nicardipine （Nic）, A/R＋HOE642, A/R ＋ H7, A/R ＋ PD98059 and control groups. The following parameters were measured in all groups, intracellular calcium concentration （[Ca^2＋]i）, cardiac cell viability, ATP content, lactate dehydrogenase （LDH） and creative phosphokinase（CK） activity in the medium, PKC and MAPK activity. The calpain（u-calpain and m-calpain） protein expression levels were measured by western blot. Results In comparison with A/R group, A/R＋nicardipine （Nic） and A/R＋Nic groups showed a marked decrease of [Ca^2＋]i, m-calpain protein expression, LDH and CK content in the medium,a higher cell viability, ATP content, activity of PKC and MAPK （P〈0. 01）. On the contrary, A/R＋H7 and A/R＋PD98059 groups showed higher LDH and CK content in the medium, and lower ATP content and cell viability as compared with A/R group （P〈0.05）. Conclusion The A/R mediated Ca^2＋ overload resulting from cardiomyocyte injury could be attenuated by blocking Ca^2＋ entry and H^＋/Na^＋ exchange, and very likely PKC and MAPK are involved in the mechanism of protection against the A/R injury of cardiomyocytes.