金雀异黄酮对糖尿病大鼠心肌损伤的保护作用

Protective Effects of Genistein on Myocardial Injury in Diabetic Rats

目的观察金雀异黄酮(genistein,Gen)对糖尿病大鼠心肌损伤的保护作用,并探讨其机制。方法雄性SD大鼠随机分为正常(N)组、糖尿病(D)组、Gen 5mg/kg治疗(L)组和Gen 25mg/kg治疗(H)组,每组8只。采用链脲佐菌素55mg/kg腹腔注射诱导1型糖尿病大鼠模型。造模成功4周后,L组和H组大鼠开始分别灌胃给予Gen溶液5mg/kg和25mg/kg。干预4周后,测定各组大鼠血流动力学指标和空腹血糖(FBG);通过HE染色和透射电镜下分别观察大鼠心肌病理形态结构和超微结构改变;测定心肌组织肿瘤坏死因子-α(TNF-α)、白介素-1β(IL-1β)、白介素-6(IL-6)、丙二醛(MDA)、谷胱甘肽(GSH)含量和Caspase-3活性;RT-PCR检测心肌组织Bcl-2和Bax mRNA表达;Western blot检测心肌硫氧还蛋白(Trx)、Trx相互作用蛋白(TXNIP)和凋亡信号调节激酶1(ASK1)的蛋白表达。结果与N组比较,D组FBG、TNF-α、IL-1β、IL-6、MDA含量和Caspase-3活性增高(P<0.01),血流动力学指标和GSH含量下降(P<0.01);心肌病理形态结构和超微结构明显损伤,心肌Bcl-2mRNA和Trx蛋白表达下降(P<0.01),Bax mRNA、TXNIP和ASK1蛋白表达增高(P<0.01)。与D组比较,L和H组中,FBG差异无统计学意义,TNF-α、IL-1β、IL-6、MDA含量和Caspase-3活性下降(P<0.05,P<0.01),血流动力学指标和GSH含量增高(P<0.05,P<0.01);心肌病理形态结构和超微结构明显改善;心肌Bcl-2mRNA和Trx蛋白表达增加(P<0.05,P<0.01),Bax mRNA、TXNIP和ASK1蛋白表达下降(P<0.05,P<0.01)。结论金雀异黄酮对糖尿病大鼠心肌损伤具有保护作用,其机制可能与减轻心肌炎症反应,调节Trx系统表达,抑制氧化应激和细胞凋亡相关。

Objective To investigate the effects of genistein （Gen） on myocardial injury in diabetic rats and explore its mechanisms. Methods Male SD rats were randomly divided into normal （N） group, diabetic （D） group, Gen 5 mg/kg treatment （L） group and Gen 25 mg/kg treatment （H） group （n=8 for each group）. Intraperitoneal injection of streptozotocin was utilized to establish type 1 diabetic rat model. After successful building models, from the fifth week, the rats in the L and H groups were daily gavaged with 5 mg/kg and 25 mg/kg Gen solution, respectively. After 4 weeks of treatment with Gen, the hemodynamic parameters and fasting blood glucose （FBG） level were measured. The morphological structure and ultrastructure of myocardium were observed using HE staining and transmission electron microscopy, respectively. The levels of tumor necrosis factor-α （TNF-α）, interleukin-lβ （IL-1β）, interleukin-6 （IL-6）, malondialdehyde （MDA）, glutathione （GSH） and Caspase-3 in myocardial tissue were measured. The levels of myocardial Bcl-2 and Bax at mRNA expression were detected using RT-PCR. The levels of myocardial thioredoxin （Trx）, Trx-interacting protein （TXNIP） and apoptosis signal regulating kinase 1 （ASK1） at protein expression were detected using Western blot. Results Compared with the N group, the FBG, TNF-α, IL-1β, IL-6, MDA and Caspase-3 levels were increased （P〈0.01）, while hemodynamie parameters and GSH content were decreased （P〈0.01）, the myocardial morphological structure and ultrastructure were damaged in the D group. The levels of Bcb2 mRNA and Trx protein expression were significantly decreased （P〈0.01）, while the levels of Bax mRNA, TXNIP and ASK1 protein expression were significantly increased （P〈 0.01） in the D group. Compared with the D group, in the L and H groups, there was no significant difference in FBG, the TNF-α, IL-1β, IL-6, MDA and Caspase-3 levels were decreased （P〈0.05, P〈0.01）, while thehemodynamic parameters and GSH content were increased （P〈0.05, P〈 0. 01）; the myocardial morphological structural and ultrastructural damages were alleviated; the levels of Bcl-2 mRNA and Trx protein expression were increased （P〈0. 05, P〈0. 01）, while the levels of Bax mRNA, TXNIP and ASK1 protein expression were significantly decreased （P〈0.05, P〈0.01）. Conclusion Gen exhibits a protective effect on myocardial injury in diabetic rats, and the mechanisms may be associated with the reduction of inflammatory reaction, the regulation of Trx system expression, and the inhibition of oxidative stress and cell apoptosis.