PINK1/Parkin通路介导的线粒体自噬在十溴联苯醚诱导肉鸡肾脏损伤中的作用

Effects of mitochondrial autophagy mediated by PINK1/Parkin pathway in kidney injury of broilers exposed to decabromodiphenyl ether

[目的]本试验旨在研究十溴联苯醚(BDE-209)暴露对肉鸡肾脏组织损伤的影响,探讨潜在的肾脏毒性作用及相关机制。[方法]选取150只1日龄雄性AA白羽肉鸡,随机分为5组,每组6个重复,每个重复5只,在5组的基础日粮中分别添加0、0.004、0.04、0.4和4.0 g·kg^(-1) BDE-209,试验期42 d。试验结束后测定血清尿素氮(BUN)和肌酐(CRE)浓度及肾脏氧化应激指标,观察肾脏组织形态结构及线粒体膜电位变化,用免疫荧光、qPCR及Western blot分析自噬相关蛋白p62、LC3-Ⅱ/LC3-Ⅰ及PINK1/Parkin mRNA水平及蛋白表达变化。[结果]与对照组相比,不同剂量BDE-209处理导致肾脏损伤,引起肾小球增大,内容物增多,肾小管水肿及胞质疏松,线粒体膜电位下降。当BDE-209剂量高于0.04 g·kg^(-1)时,血清BUN和CRE浓度均显著升高(P<0.05);0.4和4.0 g·kg^(-1) BDE-209组肾脏SOD和GSH-Px活性均显著降低(P<0.05),0.04、0.4和4.0 g·kg^(-1) BDE-209组MDA浓度均显著升高(P<0.05)。免疫荧光、qPCR及Western blot结果均显示:日粮添加BDE-209后p62表达和LC3-Ⅱ/LC3-Ⅰ值显著增大(P<0.05),PINK1蛋白表达量也显著上升(P<0.05)。[结论]BDE-209暴露诱导肉鸡肾脏氧化应激,激活PINK1/Parkin通路介导的线粒体损伤,促进自噬蛋白LC3-Ⅰ转化为LC3-Ⅱ,p62蛋白增加,阻碍自噬体的降解,最终导致肉鸡肾脏组织损伤的发生。

[Objectives]The aim of this study was to investigate the effects of decabromodiphenyl ether(BDE-209)exposed to broilers on kidney damage,and to explore the potential nephrotoxicity and mechanisms.[Methods]One day-old 150 male AA broilers were randomly allotted to 5 groups with 6 replicates per group and 5 broilers per replicate.The broilers were exposed to BDE-209 concentrations with 0,0.004,0.04,0.4,4.0 g·kg^(-1) added to a standard diet for 42 days,respectively.At the end of the experiment,the concentration of blood urea nitrogen(BUN)and creatinine(CRE)in serum as well as kidney oxidative stress indexes were measured,and the histological and morphological structure and mitochondrial membrane potential of kidney were observed.The expression of autophagy proteins involving in p62,microtubule-associated protein 1 light chain 3(LC3)and PTEN-inducible kinase 1(PINK1)/Parkin signaling pathway were analyzed by fluorescence immunohistochemistry,real-time PCR and western blot.[Results]Compared with control,kidney injury was observed at different BDE-209 treatment groups,including glomerular enlargement and cellular composition increased,renal tubular edema and cytoplasmic porosity and mitochondrial membrane potential decreased in kidney.Additionally,the levels of BUN,CRE in serum increased significantly(P<0.05)when the content of BDE-209 was upper 0.04 g·kg^(-1),and the activities of SOD and GSH-Px in 0.4 and 4.0 g·kg^(-1) BDE-209 groups decreased significantly(P<0.05),the concentration of MDA increased in 0.04,0.4 and 4.0 g·kg^(-1) BDE-209 groups(P<0.05).Moreover,the expression level of p62 and the ratio of LC3-Ⅱ/LC3-Ⅰincreased(P<0.05),and the PINK1 expression were also significantly up-regulated in kidney tissues(P<0.05).[Conclusions]BDE-209 exposure can cause kidney damage,and the underlying mechanisms may be that BDE-209 exacerbate oxidative stress,then activate PINK1/Parkin pathway to induce mitochondrial injury,promote the transformation of autophagy protein LC3-Ⅰto LC3-Ⅱand the accumulation of p62 protein,which hindere the degradation of autophagy and resulted in the renal injury.