褪黑素对镉致鸭大脑皮质毒性损伤的保护作用

Protective Effect of Melatonin on Toxic Damage Caused by Cadmium in Cerebral Cortex of Duck

为探究褪黑素对镉致鸭大脑皮质毒性损伤的保护作用,本试验将16只20日龄高邮鸭随机分为4组,分别为对照组、褪黑素组、镉组、镉与褪黑素共处理组。对照组鸭自由采食饮水;褪黑素组鸭自由饮用含有0.2 mg·L^(-1)褪黑素的水;镉组鸭自由采食拌有2 mg·kg^(-1)氯化镉的饲料;镉与褪黑素共处理组鸭自由饮用含有0.2 mg·L^(-1)褪黑素水的同时自由采食拌有2 mg·kg^(-1)氯化镉的饲料。60 d后,剖检并采集鸭大脑皮质。比色法检测大脑皮质中丙二醛(MDA)和总抗氧化能力(T-AOC)的水平,ELISA法检测肿瘤坏死因子(TNF-α)、白介素-1β(IL^(-1)β)的含量,免疫组化染色观察Nrf2核转位,免疫印迹法检测Nrf2、HO-1的蛋白表达。结果显示,与对照组相比,镉组鸭大脑皮质发生明显Nrf2核转位,T-AOC水平极显著降低(P<0.01),MDA、TNF-α、IL^(-1)β含量和Nrf2、HO-1蛋白表达量极显著升高(P<0.01);与镉组相比,镉与褪黑素共处理组鸭大脑皮质Nrf2核转位减少,T-AOC水平显著升高(P<0.05),MDA、TNF-α、IL^(-1)β含量和Nrf2、HO-1蛋白表达量显著或极显著降低(P<0.05或P<0.01)。综上,褪黑素对镉所致的鸭大脑皮质毒性损伤具有一定的保护作用。

In order to investigate the protective effect of melatonin on toxic damage caused by cadmium in cerebral cortex of duck,sixteen GaoYou ducks were randomly allocated into 4 groups:control group,melatonin-treated group,cadmium-treated group,cadmium and melatonin co-treated group.The ducks in the control group were free to eat and drink.The ducks in the melatonin group received drinking water containing 0.2 mg·L^(-1) melatonin.The ducks in the cadmium group received feeding mixed with 2 mg·kg^(-1) cadmium chloride.The ducks in the cadmium and melatonin co-treated group received drinking water containing 0.2 mg·L^(-1) melatonin plus feeding mixed with 2 mg·kg^(-1) cadmium chloride.After 60 d,the cerebral cortices of ducks were dissected and collected.The levels of malondialdehyde(MDA)and total antioxidant capacity(T-AOC)in cerebral cortex of duck were measured by colorimetry,the contents of tumor necrosis factor-alpha(TNF-α)and interleukin-1β(IL^(-1)β)were detected by ELISA,the nuclear translocation of Nrf2 was observed by immunohistochemical staining,the protein expression of Nrf2 and HO-1 was detected by Western blot.The results showed that compared with the control group,the Nrf2 nuclear translocation was obvious,the level of T-AOC showed extremely significant decrease(P<0.01),the contents of MDA,TNF-α,IL^(-1)β,the protein expression of Nrf2 and HO-1 showed extremely significant increase(P<0.01)in the cerebral cortex of duck in cadmium-treated group.Compared with the cadmium-treated group,the Nrf2 nuclear translocation was decreased,the level of T-AOC showed significant increase(P<0.05),the contents of MDA,TNF-α,and IL^(-1)β,the protein expression of Nrf2 and HO-1 showed significant or extremely significant decrease(P<0.05 or P<0.01)in the cerebral cortex of duck in cadmium and melatonin co-treated group.The results indicate that melatonin has a protective effect on toxic damage caused by cadmium in cerebral cortex of duck.