二甲双胍通过抑制内质网应激诱导的细胞凋亡对子痫前期大鼠的保护作用

Protective effect of metformin on rats with preeclampsia by inhibiting endoplasmic reticulum stress-induced apoptosis

目的研究二甲双胍对子痫前期(PE)大鼠胎盘内质网应激的影响,探讨二甲双胍对子痫前期大鼠的保护作用及机制。方法30只成功受孕Sprague-Dawley大鼠随机分为对照组、PE组和二甲双胍组,每组10只。采用N-硝基-L-精氨酸甲酯(L-NAME)诱导建立子痫前期大鼠模型,于妊娠第14~18天,PE组和二甲双胍组皮下注射L-NAME 200 mg/kg,对照组皮下注射等量生理盐水;同时,二甲双胍组给予200 mg/kg二甲双胍灌胃,PE组和对照组在相应的妊娠天数采用相等剂量的等渗盐水灌胃。检测大鼠的血压、24 h尿蛋白含量;妊娠第20天麻醉剖宫取胎,测量胎鼠的顶臀长、体重,胎盘直径、重量;RT-qPCR检测胎盘组织中内质网应激相关分子葡萄糖调节蛋白78(GRP78)和半胱氨酸天冬氨酸蛋白酶12(caspase-12)的mRNA水平;Western blot分析胎盘组织中GRP78和caspase-12蛋白水平的表达结果;TUNEL染色法分析胎盘组织的凋亡情况。结果与对照组比较,PE组大鼠收缩压水平和24 h尿蛋白水平升高(P<0.01);与PE组相比,二甲双胍干预可降低子痫前期大鼠的收缩压水平和24 h尿蛋白含量(P<0.01)。与对照组相比,PE组中子痫前期大鼠胎盘GRP78和caspase-12的mRNA和蛋白水平明显升高(P<0.01);与PE组相比,二甲双胍组中子痫前期大鼠胎盘GRP78和caspase-12的mRNA和蛋白水平降低(P<0.01)。TUNEL结果显示,PE组中凋亡细胞显著增加,二甲双胍组显著减少(P<0.05)。结论二甲双胍对子痫前期具有保护作用,其机制可能与抑制内质网应激诱导的细胞凋亡有关。

Objective To investigate the effects of metformin on placental endoplasmic reticulum stress in preeclampsia(PE)rats,and to explore the protective effect and mechanism of metformin on preeclampsia rats.Methods Thirty Sprague-Dawley rats were randomly divided into control group,PE group and metformin group,with 10 rats in each group.A rat model of preeclampsia was induced by N-nitro-L-arginine methyl ester(L-NAME).On the 14th to 18th day of pregnancy,PE group and metformin group were injected with L-NAME 200 mg/kg subcutaneously,while the control group was injected with the same amount of normal saline subcutaneously.At the same time,the metformin group was given 200 mg/kg metformin by gavage,while the PE group and the control group were given the same dose of isotonic saline by gavage on the corresponding pregnancy days.Blood pressure and 24 h urinary protein content of rats were detected.On the 20th day of gestation,the crown-rump length and weight of the fetal rats,and the diameter and weight of the placenta were measured.The mRNA levels of endoplasmic reticulum stress-related molecules GRP78 and caspase-12 in placental tissue were determined by RT-qPCR.The expression of GRP78 and caspase-12 protein in placental tissue was analyzed by Western blot.The apoptosis of placental tissue was analyzed by TUNEL staining.Results Compared with the control group,the systolic blood pressure level and 24 h urinary protein level of rats in the PE group were increased(P<0.01).Compared with the PE group,metformin intervention could reduce the systolic blood pressure level and 24 h urinary protein content of rats with preeclampsia(P<0.01).Compared with the control group,the mRNA and protein levels of GRP78 and caspase-12 in the placenta of preeclampsia rats in the PE group were significantly increased(P<0.01),while the mRNA and protein levels of GRP78 and caspase-12 in the placenta of preeclampsia rats in the metformin group were significantly decreased compared with the PE group(P<0.01).TUNEL results showed that apoptotic cells increased significantly in the PE group and decreased significantly in the metformin group.Conclusion Metformin has a protective effect on preeclampsia,and its mechanism may be related to the inhibition of endoplasmic reticulum stress-induced apoptosis.