热量限制抑制内质网应激对脑缺血再灌注损伤的影响

Effect of Calorie Restriction Inhibition of Endoplasmic Reticulum Stress on Cerebral Ischemia Reperfusion Injury

目的探讨能否通过热量限制(CR)抑制脑缺血再灌注后内质网应激通路葡萄糖调节蛋白78(GRP78)、C/EBP同源蛋白(CHOP)表达对脑缺血再灌注损伤(CIRI)起保护作用。方法选取6~8周雄性健康C57BL/6J小鼠30只,将其随机分为假手术组(Sham组)、造模组(CIRI组)及CR组,每组10只,持续干预至第28天测其质量及空腹血糖。限制饮食干预4周后,建立短暂性脑缺血再灌注模型,再灌注24h后,采用改良的GarciaJH评分评价其神经功能缺损情况,HE染色观察其光镜下结构,免疫组化及蛋白质印迹法检测GRP78、CHOP阳性蛋白的表达情况及凋亡蛋白caspase-3的表达情况。结果CR干预后,3组小鼠质量差异无统计学意义(F=0.979,P=0.389);CR组血糖较Sham组及CIRI组下降,差异有统计学意义(F=74.714,P<0.001);缺血再灌注24h后,CIRI组小鼠脑梗后GarciaJH评分较CR组及Sham组下降,CR组较CIRI组相比评分升高,但较Sham组依旧下降(F=258.221,P<0.001);CIRI组小鼠再灌注24h后GRP78、CHOP及caspase-3蛋白表达升高,差异有统计学意义(P<0.05);CR组小鼠再灌注24h后,与CIRI组相比,GRP78、CHOP及caspase-3蛋白表达降低,与Sham组相比,蛋白表达依旧升高,差异有统计学意义(P<0.05)。结论热量限制抑制小鼠脑缺血再灌注后内质网应激通路GRP78、CHOP蛋白表达对脑缺血再灌注损伤起保护作用。

Objective To investigate whether caloric restriction(CR)can inhibit the expression of glucose regulated protein 78 kD(GRP8)and C/EBP-homologous protein(CHOP)in endoplasmic reticulum stress pathway after cerebral ischemia reperfusion and protect cerebral ischemia reperfusion injury CIRI.Methods Thirty healthy male C57BL/6J mice aged 6-8 weeks were randomly divided into sham operation group(Sham group),model group(CIRI group)and CR group,with 10 mice in each group.Their body weight and fasting blood glucose were measured on day 28.After dietary restriction intervention for 4 weeks,the transient cerebral ischemia-reperfusion model was established.After 24 hours of reperfusion,the modified Garcia JH score was used to evaluate the neurological deficit,the microscopic structure was observed by HE staining,the expression of GRP8 and CHOP positive protein was detected by immunohistochemistry,and the expression of caspase-3 apoptosis protein were detected by Western blot.Results After CR intervention,there was no statistical difference in body weight among the three groups(F=0.979,P-0.389).Compared with Sham group and CIRI group,the blood glucose of CR group decreased(F=74.714,P<0.05).After 24 hours of ischemia-reperfusion,the Garcia JH score of CIRI group was lower than that of CR group and Sham group,the score of CR group was higher than that of CIRI group,but still lower than that of Sham group(F=258.221,P<0.05).The expressions of GRP8,CHOP and caspase-3 in CIRI group were higher(P<0.05).Compared with CIRI group,the expression of GRP8,CHOP and caspase-3 protein in CR group decreased 24 hours after reperfusion,and the protein increased compared with Sham group(P<0.05).Conclusion Calorie restriction can inhibit the expression of GRP8 and CHOP protein in endoplasmic reticulum stress pathway after cerebral ischemia reperfusion and protect cerebral ischemia reperfusion injury.