虾青素通过激活SIRT1通路抑制动力相关蛋白1介导的线粒体分裂减轻大鼠对比剂急性肾损伤

Astaxanthin attenuates contrast⁃induced acute kidney injury in rats by inhibiting dynamin⁃related protein 1⁃mediated mitochondrial fission through activating SIRT1 pathway

目的探讨虾青素(astaxanthin,AST)是否通过激活沉默信息调节因子2相关酶类1(silent mating type information regulation 2 homolog⁃1,SIRT1)信号通路下调动力相关蛋白1(dynamin⁃related protein 1,Drp1)介导的线粒体分裂从而减轻对比剂急性肾损伤(contrast⁃induced acute kidney injury,CI⁃AKI)。方法将40只体重160~180 g雄性Sprague⁃Dawley大鼠随机分成5组:假手术组(Sham组)、对比剂损伤组(CM组)、虾青素干预组(AST+CM组)、SIRT1抑制剂Ex527干预组(Ex527+CM组)、虾青素联合Ex527干预组(AST+Ex527+CM组)。造模72 h后行心脏取血后处死大鼠并收集肾脏组织进行后续检测。检测各组血清肌酐(Scr)和尿素氮(BUN)水平,同时检测氧化应激相关指标总超氧化物歧化酶(T⁃SOD)及丙二醛(MDA)含量;HE染色观察肾脏病理改变;透射电镜观察线粒体形态及数量;冰冻切片活性氧(ROS)染色检测ROS含量;TUNEL染色检测细胞凋亡水平;Western印迹检测SIRT1、p53、过氧化物酶体增殖物激活受体γ共激活因子1α(PGC⁃1α)、Drp1及凋亡相关蛋白Bcl⁃2、Bax的表达水平。结果(1)与CM组比较,AST+CM组Scr和BUN含量较低,T⁃SOD含量较多,MDA含量较少,而Ex527+CM组T⁃SOD含量较少,MDA含量较多(均P<0.05)。(2)与CM组比较,AST+CM组ROS表达量较低,Ex527+CM组ROS表达量较高(均P<0.05)。(3)与CM组比较,AST+CM组凋亡细胞数量较少,而Ex527+CM组凋亡细胞数量较多(均P<0.05)。(4)与CM组比较,AST+CM组SIRT1、PGC⁃1α及Bcl⁃2蛋白表达量均较高,p53、Drp1及Bax蛋白表达量均较低,Ex527+CM组SIRT1、PGC⁃1α及Bcl⁃2蛋白表达量均较低,p53、Drp1及Bax蛋白表达量均较高(均P<0.05)。结论虾青素可以通过激活大鼠SIRT1通路抑制Drp1介导的线粒体分裂从而减轻CI⁃AKI。

Objective To investigate whether astaxanthin(AST)down⁃regulates dynamin⁃related protein 1(Drp1)through activating the silent mating type information regulation 2 homolog⁃1(SIRT1)signaling pathway,thereby attenuating contrast⁃induced acute kidney injury.Methods Forty adult male Sprague⁃Dawley rats weighing 160-180 g were randomly divided into five groups:sham surgery group(Sham group),contrast medium injury group(CM group),astaxanthin⁃intervention group(AST+CM group),SIRT1 inhibitor Ex527 intervention group(Ex527+CM group),and astaxanthin combined with Ex527 intervention group(AST+Ex527+CM group).After 72 hours of modeling,heart blood was removed and kidney tissues were collected for follow⁃up testing.Serum creatinine(Scr),blood urea nitrogen(BUN),and oxidative stress⁃related indexes total superoxide dismutase(T⁃SOD)and malondialdehyde(MDA)were measured by biochemistry;hematoxylin and eosin staining was performed to observe the pathological changes in the kidney;mitochondrial morphology and number were observed by transmission electron microscopy;reactive oxygen species(ROS)levels were detected by ROS staining in frozen sections;TUNEL staining was performed to detect apoptosis level.The expression levels of SIRT1,p53,peroxisome proliferator⁃activated receptorγcoactivator⁃1α(PGC⁃1α),Drp1 and apoptosis⁃related proteins Bcl⁃2 and Bax were detected by Western blotting.Results(1)Compared with the CM group,Scr and BUN level were significantly lower,T⁃SOD level was higher and MDA level was lower in the AST+CM group,while T⁃SOD level decreased and MDA level increased after the combination of Ex527(all P<0.05).(2)ROS expression was lower in the AST+CM group compared to the CM group and higher after the combination of Ex527(both P<0.05).(3)The number of apoptotic cells was significantly reduced in the AST+CM group compared to the CM group and increased after the combination of Ex527(both P<0.05).(4)The protein expression levels of SIRT1,PGC⁃1αand Bcl⁃2 were increased and the protein expression levels of p53,Drp1 and Bax were decreased(all P<0.05)in the AST+CM group compared with the CM group,and the protein expression levels of SIRT1,PGC⁃1αand Bcl⁃2 were decreased and the protein expression levels of p53,Drp1 and Bax were increased when Ex527 was combined(all P<0.05).Conclusion Astaxanthin can inhibit Drp1⁃mediated mitochondrial fission by activating the SIRT1 pathway,thereby reducing contrast⁃induced acute kidney injury in rats.