金雀异黄酮对糖尿病大鼠心肌Nrf2/HO-1通路的影响

目的：观察金雀异黄酮(genistein，Gen)对糖尿病大鼠心肌组织核因子E2相关因子2(nuclear factor erythroid 2-related factor 2，Nrf2)/血红素氧化酶1(heme oxygenase-1，HO-1)通路的影响。 方法：将32只雄性SD大鼠随机分为 4组：正常对照(NC)组、糖尿病对照(DM)组、低剂量Gen治疗(L-Gen)组和高剂量Gen治疗(H-Gen)组(n=8)。采用腹 腔注射55 mg/kg链脲佐菌素建立糖尿病大鼠模型。造模成功后，L-Gen组和H-Gen组大鼠分别灌胃给予Gen溶液10 和50 mg/kg。8周后，测定各组大鼠左心室动力学指标和空腹血糖(fasting blood glucose，FBG)水平；测定心肌组织丙 二醛(malondialdehyde，MDA)、谷胱甘肽过氧化物酶(glutathione peroxidase，GSH-Px)、超氧化物歧化酶(superoxide dismutase，SOD)和过氧化氢酶(catalase，CAT)水平；采用透射电镜观察心肌超微结构变化；RT-PCR检测心肌组织 HO-1 mRNA表达，蛋白质印迹法检测Nrf2和HO-1蛋白表达。结果：与NC组比较，DM组左心室收缩压(left ventricular systolic pressure，LVSP)，左心室内压最大上升/下降速率(maximal rise/fall rate of left ventricular pressure，±dp/dtmax)， GSH-Px，SOD和CAT水平明显降低(均P<0.01)；左心室舒张末期压(left ventricular end-diastolic pressure，LVEDP)， FBG和MDA水平明显增高(均P<0.01)；心肌超微结构损伤明显，心肌组织Nrf2和HO-1表达明显降低(均P<0.01)。与 DM组比较，L-Gen组FBG无显著差异，±dp/dtmax和LVSP明显升高(均P<0.05)，LVEDP和MDA水平明显下降(P<0.05或 P<0.01)，GSH-Px，SOD和CAT活性明显增高(P<0.05或P<0.01)，心肌超微结构损伤减轻，Nrf2和HO-1表达升高(均 P<0.01)；H-Gen组上述指标改善更明显(P<0.05或P<0.01)。 结论：金雀异黄酮可减轻糖尿病大鼠心肌氧化应激损伤， 其机制与调节心肌Nrf2/HO-1通路，提高抗氧化酶活性相关。

Effects of genistein on Nrf2/HO-1 pathway in myocardial tissues of diabetic rats

Objective: To investigate the effects of genistein (Gen) on nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway in myocardial tissues of diabetic rats. Methods: Thirty-two male SD rats were randomly divided into 4 groups: a normal control (NC) group, a diabetic control (DM) group, a low-dose Gen treatment (L-Gen) group, and a high-dose Gen treatment (H-Gen) group (n=8). Intraperitoneal injection of streptozotocin was utilized to induce diabetic rat model. After the establishment of diabetic model, the rats in L-Gen and H-Gen groups were intragastric administration with 10 and 50 mg/kg Gen solution. Following 8 weeks, the left ventricular hemodynamic parameters and fasting blood glucose (FBG) levels were measured. The levels of malondialdehyde (MDA), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) in myocardial tissue were determined. The ultrastructure of myocardium was observed under transmission electron microscopy. The expression of HO-1 at mRNA level in myocardial tissue was detected by RT-PCR. The protein levels of Nrf2 and HO-1 in myocardial tissue were detected by Western blotting. Results: Compared with the NC group, left ventricular systolic pressure (LVSP), maximal rise/ fall rate of left ventricular pressure (±dp/dtmax), and the levels of GSH-Px, SOD and CAT were decreased (all P<0.01), while the left ventricular end-diastolic pressure (LVEDP), FBG and MDA were increased (all P<0.01) in the DM group. The myocardial ultrastructure was obviously damaged, and the expressions of myocardial Nrf2 and HO-1 were significantly decreased (both P<0.01) in the DM group. Compared with the DM group, there was no difference in FBG in the L-Gen group, while ±dp/dtmax and LVSP were significantly increased (all P<0.05), and LVEDP and MDA were decreased (P<0.05 or P<0.01), and the levels of GSH-Px, SOD and CAT were increased (P<0.05 or P<0.01) in the L-Gen group. The myocardial ultrastructure damage was alleviated and the expressions of Nrf2 and HO-1 were increased (both P<0.01) in the L-Gen group. Compared with L-Gen group, the aforementioned indexes were improved in the H-Gen group (P<0.05 or P<0.01). Conclusion: Genistein exerted antioxidant effects on myocardial injury in diabetic rats, and the mechanisms might be related to regulating the Nrf2/HO-1 pathway and enhancing the activities of antioxidant enzymes in myocardial tissues.