肌肽对高糖诱导的H9c2细胞损伤的拮抗作用

Carnosine protects against high glucose-induced injury in H9c2 cells

目的:探讨肌肽对高糖诱导的H9c2心肌细胞损伤的拮抗作用。方法:体外培养大鼠心肌细胞H9c2,细胞分为正常对照组、高糖损伤组和肌肽预保护组。MTT法检测细胞存活率,DCFH-DA荧光探针检测细胞内活性氧(ROS)水平,并利用Western blotting检测半胱氨酸天冬氨酸蛋白酶(caspase-8、caspase-9和caspase-3)活性片段的表达。结果:细胞存活率随着高糖刺激时间和高糖浓度的增加而逐渐降低,而肌肽预保护组细胞的存活率显著高于高糖处理组(P<0.05)。高糖组ROS水平比正常对照组明显增加(P<0.05),而肌肽预保护组与高糖组相比ROS水平降低(P<0.05)。高糖组caspase-8、caspase-9和caspase-3活性片段表达量比正常对照组显著升高(P<0.05),而肌肽预保护组与高糖组相比,caspase-9和caspase-3活性片段表达量显著降低(P<0.05),而活化caspase-8相对含量无明显变化(P>0.05)。结论:肌肽能够拮抗高糖诱导的H9c2心肌细胞氧化应激和凋亡损伤。

AIM： To explore the protective effect of carnosine （Car） on cardiomyocytes with high glucose （HG）-induced injury. METHODS：Rat H9c2 cardiomyocytes were cultured in vitro and divided into three groups： normal control （NC） group, HG group and Car pretreatment （Car＋HG） group. The survival rate of H9c2 cells was measured by MTT assay. Intracellular level of reactive oxygen species （ROS） was detected by fluorescent probe DCFH-DA. The protein expression of caspase-8, caspase-9 and caspase-3 was determined by Western blotting. RESULTS：The survival rate of H9c2 cells decreased with the increases in glucose concentration and time, while pretreatment with 20 mmol/L Car could increase the survival rate significantly （P〈0.05）. The intracellular level of ROS in HG group was significantly increased compared with NC group （P〈0.05）, while that in Car＋HG group was significantly decreased compared with HG group （P〈0.05）. The expression of caspase-8, caspase-9 and caspase-3 proteins in HG group was significantly increased compared with NC group （P〈0.05）. Compared with HG group, the expression of caspase-9 and caspase-3 was significantly decreased in Car＋HG group （P〈0.05）, but the expression of caspase-8 did not obviously change （P〉0.05）. CONCLUSION：Carnosine can protect H9c2 cells against the injury of oxidative stress and apoptosis induced by high glucose.