细胞凋亡在雷公藤甲素所致大鼠急性肾损伤中的作用及其发生机制

Role of apoptosis in triptolide-induced acute nephrotoxicity and possible mechanisms in rats

目的观察雷公藤甲素所致大鼠急性肾损伤情况,研究细胞凋亡在雷公藤甲素所致大鼠急性肾损伤中的作用及其发生机制。方法大鼠分别单次ip给予雷公藤甲素1、2 mg/kg,给药后48 h心脏采血,检测血浆尿素氮(BUN)与肌酐(Scr)水平;肾脏HE染色,光镜下观察肾组织形态学改变;应用原位末端转移酶标记法(TUNEL)检测肾组织细胞凋亡情况;利用免疫组织化学染色法结合计算机图像分析技术检测肾组织内凋亡相关蛋白的表达情况,并利用RT-PCR技术测定肾组织内凋亡相关蛋白调控基因的表达。结果雷公藤甲素2个剂量组均可见大量肾小管上皮细胞凋亡,且高剂量的作用显著大于低剂量,细胞凋亡与肾功能改变相关;肾组织中Bax、Bid、Bad、Fas以及FasL蛋白表达明显增多,且呈剂量依赖性,而Bcl-2的表达未见明显改变。结论一次性ip大剂量雷公藤甲素会在短时间(48 h)内造成严重的肾损伤,肾小管上皮细胞凋亡是雷公藤甲素所致大鼠急性肾损伤的重要组织学基础之一,且Bcl-2家族以及Fas/FasL在雷公藤甲素诱导的肾小管上皮细胞凋亡的过程中起重要作用。

Objective To investigate the role of apoptosis in triptolide-induced acute nephrotoxicity and the possible mechanisms in vivo.Methods Thirty male SD rats were randomly divided into control and two testing groups.The rats of two testing groups were ip injected with triptolide solution at doses of 1 and 2 mg/kg of body weight,respectively,and the rats of the control group were ip injected with 0.9% physiological saline instead.Testing rats were killed 48 h after the injection;Blood samples were collected and both kidneys were removed.The BUN and Scr concentrations in plasma were measured,and renal histology was examined by HE staining.TUNEL staining was performed to evaluate apoptosis of renal tissue.Renal expression of apoptosis related proteins Bcl-2,Bax,Bid,Bad,Fas,and FasL proteins,as well as corresponding regulating genes were assessed by immuno-histochemical staining and real-time PCR.Results After injection,a large number of apoptotic tubular cells appeared corresponding to the increases of BUN and Scr concentrations.Furthermore,increased expression of Bax,Bid,Bad,Fas,and FasL was detected at both protein and mRNA levels,but the expression of Bcl-2 did not differ among the three groups.Conclusion These results suggest that apoptosis of tubular cells plays a key role in the pathogenesis of triptolide-induced acute nephrotoxicity,and Bcl-2 family,as well as Fas and FasL,is involved in this process.