促红细胞生成素通过调节未折叠蛋白反应减轻顺铂所致的肾小管上皮细胞凋亡

Erythropoietin attenuates cisplatin-induced nephrotoxicity by regulating unfolded protein response

目的:探讨促红细胞生成素(EPO)能否通过调节未折叠蛋白反应减轻顺铂(CP)诱导的肾小管上皮细胞凋亡。方法:健康雄性SD大鼠随机分为3组(每组12只),包括正常对照组(control组)、CP组和CP+重组人EPO组(CP+rHuEPO组)。顺铂或生理盐水注射96 h后处死SD大鼠,留取血液和肾脏组织,检测血尿素氮(BUN)和血清肌酐(SCr)水平,PAS染色光镜观察肾脏形态结构变化;TUNEL染色检测肾小管上皮细胞凋亡;采用Western blotting法、免疫组化及激光共聚焦技术检测EPO受体(EPOR)和葡萄糖调节蛋白78(GRP78)蛋白表达。结果:与control组比较,CP组与CP+rHuEPO组大鼠BUN及SCr水平均显著升高(P<0.05),TUNEL染色显示凋亡细胞阳性率显著上升(P<0.05),EPOR及GRP78蛋白表达显著上调(P<0.05);PAS染色光镜示CP组肾脏组织结构出现明显损伤性变化;与CP组比较,CP+rHuEPO组SCr水平显著降低(P<0.05),凋亡细胞阳性率显著下降(P<0.05),EPOR及GRP78蛋白表达下调(P<0.05),肾脏病理损伤减轻。结论:EPO可以减轻顺铂引起的肾损害,其机制可能与调节未折叠蛋白反应减轻肾小管上皮细胞凋亡相关。

AIM： To investigate whether erythropoietin （EPO） attenuates cisplatin （CP）-induced nephrotoxic- ity by regulating unfolded protein response （UPR）. METHODS： Healthy male Sprague-Dawley （SD） rats were randomly divided into control group （n = 12）, CP group （n = 12） and CP combined with recombinant human erythropoietin （CP ＋ rHuEPO） group （n = 12）. All animals were sacrificed 96 h after injection of normal saline or CP. Blood samples and kid- ney tissues were collected to evaluate blood urea nitrogen （BUN）, serum creatinine （SCr） and the morphological alteration of the kidneys. The apoptosis of the renal tubular epithelium cells was detected by TUNEL. The protein levels of EPO re- ceptor （EPOR） and glucose-regulated protein 78 （GRP78） were measured by the methods of Western blotting, immuno- histochemistry and immunofluorescent staining. RESULTS： Compared with control group, significant increases in the lev- els of SCr and BUN were observed in CP group and CP ＋ rHuEPO group, whereas SCr was significantly lower in the rats treated with rHuEPO after CP injection than that in the CP-injected rats. The histological structure of the kidneys observed by PAS staining showed marked structural damage in CP group. No or very little structural damage was detected in control group and CP ＋ rHuEPO group. The observations of morphological evidence showed that CP caused an increase in TUNEL- positive cells and the apoptotic cell death induced by CP was significantly abrogated by rHuEPO at 96 h. The over-expres- sion of CP-induced EPOR and GRP78 was suppressed by rHuEPO. CONCLUSION： CP activates UPR in renal tubular epithelial cells. EPO has a protective effect on the kidneys with CP-induced nephrotoxicity, which may be related to the regulation of UPR-induced apoptosis.