过表达APE1对糖尿病心肌病小鼠心肌损伤的保护作用及机制的研究

Protective Effects and Mechanism of APE1 Overexpression on Myocardial Damage in Mice with Diabetic Cardiomyopathy

目的探讨APE1过表达在糖尿病心肌病小鼠中对心肌损伤的保护作用及机制。方法采用雄性APE1转基因PCR阳性小鼠与其同窝雄性阴性对照小鼠分别给予正常饮食和高糖高脂饮食8周后,按70mg·kg-1的标准腹腔注射链脲佐菌素(STZ)或相应剂量的柠檬酸钠缓冲液72h后,若空腹血糖(FBG)>11.1mmol·L-1视为造模成功。后随机分为4组:普通饲料喂养的阴性小鼠对照组(CON组)、普通饲料喂养的APE1转基因小鼠组(CON+APE1组)、高糖高脂饮食结合STZ的阴性小鼠对照组(DCM组)和高糖高脂饮食结合STZ的APE1转基因小鼠组(DCM+APE1组),每组各15只小鼠。再培养8周后,分别测定小鼠体重、血糖值;镜下观察心肌细胞及组织病理变化;酶联免疫吸附法(ELISA)检测心肌组织活性氧(ROS),丙二醛(MDA),超氧化物歧化酶(SOD)及炎性因子IL-6、IL-1β和肿瘤坏死因子-α(TNF-α)的含量。结果与DCM组相比,DCM+APE1组的糖尿病心肌病小鼠的体重有所增加,而FBG有所下降(P<0.05);抑制心肌细胞肥大、凋亡及心肌纤维化的程度;增强SOD活性,降低MDA和ROS含量(P<0.05);降低组织中炎性因子IL-1β,IL-6,TNF-a的含量(P<0.05)。结论 APE1对糖尿病心肌病小鼠的心肌细胞损伤具有保护作用,其机制可能与APE1的抗氧化应激和抗炎作用有关。

Objective To investigate the protective effect and mechanism of APE1 overexpression on myocardial injury in mice with diabetic cardiomyopathy.Methods Male APE1 transgenic PCR-positive mice and their counterparts(PCR-negative mice)were given a normal diet or a high-sugar and high-fat diet for 8 weeks,respectively.And then,streptozotocin(STZ)was injected intraperitoneally at a standard of 70 mg·kg-1 or sodium citrate buffer solution of same volume.If fasting blood glucose(FBG)>11.1 mmol·L-1 after 72 hours’ injection,DCM animal models were considered successful.These mice were then divided into 4 groups:the control group of PCR-negative mice fed with normal diet(CON group),the group of APE1 transgenic mice fed with normal diet(CON+APE1 group),the group of PCR-negative mice fed with a high-sugar and high-fat diet combined with STZ group(DCM group)and the group of APE1 transgenic mice fed with a high-sugar and high-fat diet combined with STZ group(DCM+APE1 group).There were 15 mice in each group.After another 8-week feeding,body weight and FBG were measured respectively.The myocardial cells and matrix were observed under the microscope.The enzyme-linked immunosorbent assay(ELISA)was used to detect reactive oxygen species(ROS),malondialdehyde(MDA),super-oxidation content of dismutase(SOD)and inflammatory factors interleukins(IL)IL-6,IL-1β and tumor necrosis factor-α(TNF-α).Results Compared with DCM group,the body weight increased and FBG decreased in DCM+APE1 group(P<0.05).And in DCM+APE1 group,the degree of myocardial cell hypertrophy,apoptosis and myocardial fibrosis was inhibited.SOD activity was enhanced and MDA and ROS contents were lower(P<0.05).And the contents of inflammatory factors IL-1β,IL-6,TNF-a were reduced(P<0.05).Conclusion APE1 has protective effects on myocardial damage in diabetic cardiomyopathy mice and its mechanism may be related to the antioxidant stress and anti-inflammatory effects of APE1.