高铜诱导肉鸡心肌氧化损伤和内质网应激

High level of copper induces oxidative damage and endoplasmic reticulum stress in myocardium of broilers

探讨高铜对肉鸡心肌氧化损伤和内质网应激的影响,将48羽1日龄白羽肉鸡随机平均分为4组,分别饲喂对照日粮(Cu 11 mg/kg,对照组)和高铜日粮(Cu 110 mg/kg,高铜I组;Cu 220 mg/kg,高铜Ⅱ组;Cu 330 mg/kg,高铜Ⅲ组)。49日龄时进行心脏采集,制备切片观察心脏组织病理学变化,检测心肌总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性、谷胱甘肽还原酶(GR)活性及丙二醛(MDA)含量的变化,实时荧光定量PCR检测内质网应激相关基因GRP78、GRP94、eIF2α、ATF6、XBP1、CHOP的mRNA转录水平,Western blot检测GRP78蛋白表达水平。结果显示,与对照组相比,高铜组心肌纤维间隙增宽;随着日粮中铜含量的增加,心脏组织中T-AOC、SOD、CAT和GR活力下降,MDA含量显著升高(P<0.05),GRP78、GRP94、eIF2α、ATF6、XBP1和CHOP mRNA表达量升高,GRP78蛋白表达显著上调(P<0.05)。结果表明,高铜可以诱导心肌氧化损伤和内质网应激。

To investigate whether high level of copper can induce oxidative damage and endoplasmic reticulum stress in heart of broilers,48 one-day-old healthy white feather broilers were randomly divided into 4 groups with 12 birds in each-group in this study.The broilers were fed with diets as follows:control diet(Cu 11 mg/kg,control group),and high-Cu diets(Cu 110 mg/kg,high-Cu group I;Cu 220 mg/kg,high-Cu group Ⅱ;Cu 330 mg/kg,high-Cu group Ⅲ).The heart tissues were collected on day 49 for pathologic examination.The activities of total antioxidant capacity(T-AOC),superoxide dismutase(SOD),catalase(CAT),glutathione reductase(GR) and the content of malondialdehyde(MDA) were detected.Moreover,the mRNA expression levels of GRP78,GRP94,eIF2α,ATF6,XBP1 and CHOP were measured by real-time quantitative PCR(RT-qPCR),and the protein expression of GRP78 was determined by Western blot.The results showed that the myocardial fiber gap in the high-Cu group was widened compared to control group.With the increase of dietary Cu,the activities of T-AOC,SOD,CAT,GR were significantly decreased and the content of MDA was markedly increased(P<0.05).Furthermore,the mRNA expression levels of GRP78,GRP94,eIF2α,ATF6,XBP1 and CHOP were increased in high-Cu group compared to control group,and the protein expression level of GRP78 was also up-regulated remarkedly(P<0.05).These results suggested that high level of Cu could induce oxidative damage and endoplasmic reticulum stress in myocardium of broilers.