夹竹桃麻素对高草酸尿症大鼠肾脏氧化应激损伤的保护作用

Protective effect of apocynin on renal oxidative injury in a rat model of hyperoxaluria

目的观察NADPH氧化酶特异抑制剂夹竹桃麻素（apocynin）对高草酸尿症大鼠肾脏氧化应激（OS）损伤的保护作用。方法自由饮用含有0.8％乙二醇的水4周建立高草酸尿症sD大鼠模型。大鼠按随机数字表法分为4个组：空白组、高草酸尿症组、apocynin干预组、apocynin对照组。后两组给予apocynin（0．2g·kg^-1·d^-1）灌胃，对照组给予正常饮水。4周后检测大鼠肾脏OS指标（尿H2O2和8-异前列腺素），以及Ccr及肾脏／体质量比值。免疫组化观察NADPH氧化酶亚基p47phox在肾脏中的表达位置。RT—PCR和免疫印迹法分别检测肾组织NADPH氧化酶亚基p47phox、gp91phox、Nox-1 mRNA以及p47phox蛋白的表达水平。结果p47phox在各组肾脏中均有广泛的表达，包括肾皮质区、内髓区、外髓区等。与空白组比较，高草酸尿症组大鼠尿H2O2和8-异前列腺素水平显著升高，Ccr降低，肾脏／体质量比值增高（均P〈0．05）；肾脏p47phox、gp91phox和Nox-1的mRNA表达均显著增加（均P〈0．05），p47phox蛋白表达也增多（P〈0．01）。apocynin干预治疗可抑制肾脏p47phox、Nox-1 mRNA及p47phox蛋白的表达，但gp91phox mRNA表达未明显减少，而大鼠尿H2O2和8-异前列腺素水平下降，Ccr增加，肾脏／体质量比值减少，但仍高于对照组水平。结论NADPH氧化酶是高草酸尿症诱导大鼠肾脏OS损伤过程中活性氧形成的来源之一。使用apocynin抑制NADPH氧化酶活性可部分减轻肾脏的OS损伤程度，保护肾功能。

Objective To investigate the protective effect of apocynin against renal oxidative injury in a rat model of hyperoxaluria. Methods Animal model of hyperoxaluria was established by administration of 0.8% ethylene glycol （EG） to adult male Sprague-Dawley rats in drinking water for 4 weeks. Simultaneous treatment with apocynin （0.2 g·kg^-1·d^-1） by intragastric administration were performed in the rats. Markers of oxidative stress（OS） state, urinary H2O2 and 8- （so-prostaglandin IP）, and renal injury were assessed at the end of the study. Expression and localization of NADPH oxidase subunits （p47phox, gp91phox, Nox-1） in kidneys were examined by immunohistochemistry, real-time PCR and Western blot, respectively. Results p47phox expressed widely in kidneys of model rats, including renal cortex, inner medulla and outer medulla. Compared with the control, OS and renal injury occurred in rats receiving EG, in accordance with the up-regulated expression of NADPH oxidase subunits in kidneys. Treatment with apocynin significantly reduced the excretion of urinary H2O2 and 8-IP, improved the ereatinine clearance and the kidney/body weight, with the down-regulated expression of NADPH oxidase subunits （except gp91phox mRNA） in kidneys, but the levels of OS markers in apocynin-treated rats were still higher than thoset of normal controls. Conclusions The increased expression of NADPH oxidase subunits is suggested to be partially accounted for the development of renal OS in this rat model of hyperoxaluria. Apocynin treatment is effective for renal protection in this model.