表没食子儿茶素没食子酸酯对大鼠肾脏缺血再灌注损伤的保护作用

Protective effect of EGCG on renal ischemia-reperfusion injury

目的探讨表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)对大鼠肾缺血再灌注损伤的保护作用及作用机制。方法将50只雄性SD大鼠随机分为假手术组、模型组和EGCG(低,中,高)剂量组,每组10只。利用血管夹夹闭大鼠双侧肾蒂45 min,构建大鼠肾缺血再灌注损伤模型。恢复肾脏血流灌注24 h后,处死大鼠,收集血清。利用ELISA法检测血清肌酐(SCr)、血清尿素氮(BUN)、干扰素(interferon-γ,IFN-γ)、肿瘤坏死因子(tumor meerosis factor-α,TNF-α)和白介素6(interleukin-6,IL-6)表达水平;取肾脏标本PAS染色法观察肾组织病理形态;黄嘌呤氧化酶法检测过氧化氢酶(Cata-lase,CAT)、谷胱甘肽过氧化物酶(glutathione peroxidase,GPx)和超氧化物歧化酶(superoxide dismutase,SOD)的活性;硫代巴比妥酸法检测丙二醛(malonaldehyde,MDA)的含量;免疫蛋白印记(Western blotting)法检测p53、Wnt、p21和β-catenin表达水平;实时定量PSCR(RTPSCR)检测肾脏IFN-γ、TNF-α和IL-6含量。结果与假手术组相比,模型组SCr、BUN、IFN-γ、TNF-α、IL-6、MDA、p53、Wnt、p21、β-catenin、IFN-γ、TNF-α和IL-6表达水平以及肾组织病理改变均明显增高,而CAT,GPx和SOD活性明显降低。与模型组相比,EGCG高剂量组SCr、BUN、IFN-γ、TNF-α、IL-6、MDA、p53、Wnt、p21、β-catenin、IFN-γ、TNF-α和IL-6表达水平以及肾组织病理改变均明显降低,而CAT,GPX和SOD活性明显增高。结论 EGCG预处理可通过抑制炎症和氧化应激而减轻肾脏缺血再灌注损伤,其作用机制与抑制Wnt/β-catenin/p53信号通路激活相关。

Objective To explore the protective effects of EGCG on renal ischemia-reperfusion injury （IRI） and the mechanism. Methods Male SD rats were randomly divided into Sham, IRI and EGCG （low, middle and high dose） groups. The model of IRI was induced by clamping the bilateral- renal pedicles for 45min and removing right kidney, successive reperfusion for 24 h. The levels of SCr, BUN, IFN-γ, TNF-α and IL-6 in the serum were examined by ELISA. The expression levels of Wnt, β-catenin, p53 and p21 were detected by Western blotting. The expression of MDA was meas- ured by TBA. Moreover, the morphrologic changes of kidney and the activation of CAT, GPX and SOD in the kidney were measured by PAS and hydrogen peroxide enzyme, respectively. Results Com- pared to Sham group, the levels of SCr, BUN, IFN-γ, TNF-α, IL-6, Wnt, γ-βcatenin, p53, p21 and MDA were significantly increased, the pathological changes of the kidney significantly aggravated and activities of CAT, GPx and SOD significantly reduced in the kidney in the IRI group. Compared to IRI group, the levels of SCr, BUN, IFN-γ, TNF-α, IL-6, Wnt, t3-catenin, p53, 1021 and MDA were sig- nificantly reduced, pathological changes of the kidney alleviated and activities of CAT, GPx and SOD in the kidney increased in the EGCG group. Conclusions EGCG preconditioning can reduce kidney IRI by suppressing inflammation and oxidative stress in rats, which may be associated with the inhibition of Wnt/β-catenin/p53 signal pathway activation.