全氟辛酸对大鼠肝脏氧化应激与PPARα及其所调控的CYP4A1基因表达的影响

Effects of perfluorooctanoic acid on oxidative stress and PPARα and its related CYP4A1 gene expression in rat liver

目的研究全氟辛酸(perfluorooctanoic acid,PFOA)致大鼠肝脏氧化应激以及对过氧化物酶体增殖剂激活受体(PPAR)α、细胞色素P450(CYP)4A1基因以及PPARα蛋白表达的影响。方法将28只雄性SD大鼠随机分为4组,每组7只,分别为对照组(双蒸水)、低剂量组[PFOA 1 mg/(kg·d)]、中剂量组[PFOA 5 mg/(kg·d)]和高剂量组[PFOA 25 mg/(kg·d)],连续14 d经口灌胃后处死,称重肝脏并计算肝脏系数。用生化检测试剂盒测定大鼠肝脏组织总超氧化物歧化酶(T-SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性以及丙二醛(MDA)含量;荧光定量PCR检测PPARα及CYP4A1基因的mRNA转录水平;Western blot检测PPARα蛋白表达水平。结果从灌胃第5天开始,高剂量组体重与对照组差异有统计学意义(P<0.05)。中、高剂量组肝脏重量和肝脏系数与对照组相比,均显著升高(P<0.05)。低剂量组大鼠肝脏SOD和GSH-Px活性与对照组相比显著升高(P<0.05);中、高剂量组大鼠肝脏MDA含量是对照组2.5倍和3.5倍(P<0.05)。低、中、高剂量组PPARα及其所调控的CYP4A1基因mRNA表达水平均被显著诱导升高。低、中、高剂量组PPARα蛋白表达均上调(P<0.05)。结论 PFOA暴露可导致大鼠肝脏氧化应激,从而引起SOD和GSH-Px以及MDA的变化。同时,PFOA暴露可诱导大鼠肝脏的PPARα、CYP4A1基因表达上调,可增强脂肪酸β氧化,从而导致脂质过氧化产生,对大鼠肝脏有明显的毒性作用。

Objective To study the effects on oxidative stress and the expression of PPARα-related genes and protein in the liver of rats induced by pentadecafluorooctanoic acid（ PFOA）. Methods A total of 28 male SD rats were randomly divided into four groups： control group： double distilled water,low dose group： PFOA 1 mg/（ kg·d）,middle dose group： PFOA 5 mg/（ kg·d）,high dose group： PFOA 25 mg/（ kg·d）,and were administrated by gavage once a day for 14 days take the organization after anesthesia,according to the follow-up experiments need treatment. The activity of oxidative stressrelated enzymes and the content of malondialdehyde（ MDA） in liver tissue were detected.The mRNA levels of peroxisome proliferators-activited receptors α（ PPARα） and cytochrome P4504A1（ CYP4A1） were detected by real-time PCR. The protein expression of PPARα was detected by Western blot. Results There was significant difference between high dose group and control group of the body weight（ P 0. 05）. The liver weight and relative liver weight of the middle and high dose groups were significantly higher than those of the control group（ P 0. 05）. The activity of superoxide dismutase（ SOD） and glutathione peroxidase（ GSH-Px） in the liver of the low dose group were significantly higher than that of the control group（ P 0. 05）. The content of MDA in liver of middle and high dose groups were increased by 2. 5 times and 3. 5 times compared with that of control group（ P 0. 05）. The expression of PPARα and its regulated CYP4A1 mRNA were significantly increased in low,middle and high dose groups. The expression of PPARα protein in the low,middle and high dose groups were up-regulated.Conclusion PFOA exposure can lead to oxidative stress in rat liver, resulting in antioxidant enzymes SOD and GSH-Px and MDA changes. At the same time,PFOA exposure induced up regulation of PPARα and CYP4A1 in the liver of rats to enhance theβ-oxidation of fatty acids,leading to lipid peroxidation,which has obvious toxic effects on rat liver.