臭氧氧化后处理对大鼠肾缺血再灌注损伤慢性纤维化的作用

目的 观察臭氧氧化后处理(简称"臭氧后处理")对大鼠肾缺血再灌注损伤远期改变的影响.方法 通过随机数字表将36只SD雄性成年大鼠分为假手术(Sham)组、缺血再灌注(I/R)组和臭氧后处理(Postcond)组,每组12只.Sham组:腹部正中切开后充分游离并显露双侧肾脏,切除右肾结束手术.I/R组:切除右肾后,无创血管夹阻断肾蒂45 min,随后开放肾血管.Post-cond组:同样操作夹闭左肾蒂45 min,在恢复肾动静脉血灌流后,连续10 d经直肠给予臭氧治疗.术后2周测定肾功能,包括血清肌酐(Scr)和尿素氮(BUN)水平浓度.分别于术后2周及8周观察肾组织病理变化,蛋白水平上检测平滑肌肌动蛋白(α-SMA)、细胞转化生长因子(TGF-β1)和信号传导蛋白(Smad-2)在肾脏的表达.结果 术后2周各组肾功能已经基本恢复正常(P>0.05).Postcond组引起的肾小管间质损伤接近于Sham组,而I/R组HE显示仍有肾小管细胞萎缩变形,炎性细胞浸润甚至空泡形成.同时Masson染色显示小管间质胶原纤维增加(P<0.05).Postcond组的α-SMA、TGF-β1和Smad-2蛋白的表达高于Sham组,但是都明显低于其在I/R组的表达(P<0.05).结论 臭氧可以减轻肾缺血再灌注损伤从而减少肾纤维化,其机制可能与抑制TGF-β1/Smad-2信号通路,降低α-SMA、TGF-β1和Smad-2蛋白在肾组织的表达有关.

Effect of ozone oxidative postconditioning on chronic kidney fibrosis induced by ischemic reperfusion in rats

Objective To investigate the effect of ozone oxidative postconditioning on the long-term pathological changes after renal ischemia reperfusion injury in rats. Methods 36 adult male SD rats were divided into three groups by random number table method, 12 rats in each group. The rats in the sham operation group were excised only the right kidney, but the rats in the ischemia reperfusion group and the ozone postconditioning group were first excised the right kidney, then their kidney vessels were blocked for 45 min by noninvasive endoclip before reopening. After reperfusion of the kidney vessels, the rats in the ozone postconditioning group were treated rectally with ozone lasting for 10 days. The serum levels of creatinine( Scr) and urea nitrogen( BUN) were examined in all rats at 2 weeks after operation for renal func-tion evaluation. At 2 and 8 weeks after operation, the pathological changes in kidney tissue were observed, and the expression levels ofα-smooth muscle actin (α-SMA), transforming growth factor-β1 (TGF-β1) and signaling protein (Smad-2) in rats' kidney were tested in a protein level. Results The BUN and Scr levels largely turned to normal at 2 weeks after operation in the three groups (P>0. 05). At the moment, the pathological changes of tubulointerstitial injury in the ozone postconditioning group were similar to those in the sham opera-tion group, but in the ischemia reperfusion group there still were atrophic and deformed tubular cells, infiltrated inflammatory cells and even cavitation by HE staining, and development of tubulointerstitial fibrosis by Masson staining (P<0. 05). The levels of protein expression ofα-SMA, TGF-β1 and Smad-2 in the ischemia reperfusion group were all significantly higher than those in the other two groups ( P<0. 05), although these expression levels in the ozone postconditioning group were also higher. Conclusion Application of the ozone post-condtioning could attenuate renal fibrosis induced by ischemia reperfusion injury in rats, and its internal mechanism might be inhibition of the TGF-β1/Smad-2 signaling pathway and down-regulation of protein expression ofα-SMA, TGF-β1 and Smad-2 in the kidney tissue.