脑肠肽改善梗阻性肾病中肾脏纤维化和细胞凋亡的实验研究

Ghrelin attenuates renal fibrosis and apoptosis of obstructive nephropathy

目的:研究脑肠肽对肾间质纤维化及肾细胞凋亡的改善作用及其作用机制。方法:将雄性Sprague-Dawley(SD)大鼠随机分为4组,假手术组+盐水或脑肠肽治疗组,模型组+盐水或脑肠肽治疗组。对模型组大鼠行左侧输尿管结扎术建立单侧输尿管梗阻(UUO)动物模型。术后7 d和14 d分批处死大鼠,留取梗阻侧肾组织行Masson染色以观察各组大鼠肾组织病理改变,通过免疫组化分析α平滑肌肌动蛋白(α-SMA)、转化生长因子β1(TGF-β1)、磷酸化的Smad3(p-Smad3)的水平蛋白表达,用realtime-PCR(RT-PCR)法检测α-SMA、TGF-β1的m RNA表达水平。用TUNEL染色法标记凋亡肾脏细胞。结果:脑肠肽通过减少胶原产生,抑制细胞外基质沉积和减少α-SMA蛋白表达改善肾脏纤维化。同时,脑肠肽通过阻断TGF-β1/Smad3信号通路,抑制肌成纤维细胞聚集。另外,脑肠肽改善UUO诱导肾小管细胞凋亡。结论 :脑肠肽可以减少UUO诱导的肾脏纤维化、改善肾细胞凋亡,有望成为治疗梗阻性肾病肾脏纤维化的药物。

Objective To investigate the effect and underlying mechanisms of ghrelin in a rat model of renal fibrosis. Methods Male Sprague-Dawley rats were divided into 4 groups, including sham operation ＋ saline or brain gut peptide treatment group, model ＋ saline or brain gut peptide treatment group. Unilateral ureteral obstruction （UUO） was established by left ureteral ]igation. 7 days and 14 days after operation, the rats were sacrificed, while the kidney tissue of obstruction side was harvested for pathlogieal changes through Masson coloration. Expression of α-smooth muscle actin （α-SMA）, transforming growth factor betal （TGF-β1） and phosphorylated Smad3 （p-Smad3） in renal tissues were analyzed through immunohistochemistry. Expression of α- SMA and TGF-β1 mRNA was detected by real-time-PCR. Apoptosis kidneys cells were marked with TUNEL. Results Ghrelin inhibited renal fibrosis by reducing the production of collagen, restraining extraeellular matrix （ECM） deposition and decreasing the expression of ct-SMA. Meanwhile, ghrelin inhibited the accumulation of myofibroblasts by blocking the transforming growth factor-β1/Smad3 （TGF-β1/Smad3） signaling pathway. Moreover, ghrelin could attenuate renal tubular cell apoptosis induced by UUO injury. Conclusion Ghrelin can reduce renal fibrosis and renal cell apoptosis induced by UUO, demonstrating that ghrelin is a potent antifibrotic agent that may have therapeutic potential for patients with obstructive nephropathy.