钼镉联合诱导对鸭抗氧化指标及脾脏凋亡基因mRNA表达的影响

Effects of co-induction of molybdenum and cadmium on antioxidant indexes and apoptosis genes mRNA expression in duck spleens

为了研究钼镉联合诱导对鸭抗氧化指标和脾脏凋亡基因mRNA表达的影响,以(NH4)6Mo7O24·4H2O和3CdSO4·8H2O分别作为钼源和镉源,将120只11日龄体质量相近、体况健康的鸭随机分为对照组、低钼组、高钼组、镉组、低钼镉组和高钼镉组,每组20只,对照组给予基础饲料,处理组在每千克基础饲料中分别添加钼15 mg、钼100 mg、镉4 mg、钼15 mg+镉4 mg、钼100 mg+镉4 mg,试验期为60 d。于试验30,60 d,各组取10只鸭,收集血液及脾脏组织,检测血清中抗氧化指标、脾脏组织CP基因和凋亡有关基因mRNA表达水平及观察其超微结构。结果显示:30 d,MDA含量联合组显著高于对照组(P<0.05),T-AOC高钼镉组显著低于其余各组(P<0.05),XOD活性联合组显著低于对照组(P<0.05);60 d,SOD活性、T-AOC处理组有下降趋势,且联合组显著低于对照组、单独组(P<0.05或P<0.01),XOD活性联合组显著低于对照组(P<0.05),而NOS、CAT活性和MDA含量有升高趋势,且联合组显著高于其他各组(P<0.05);60 d,除低钼组外,其余各组CP mRNA表达量显著低于对照组(P<0.05),而联合组Bak-1、Caspase-3 mRNA表达量极显著高于对照组、单独组(P<0.01);各组之间Bcl-2 mRNA表达量无显著差异(P>0.05);同时,电镜观察发现处理组脾脏组织细胞发生核变形、固缩,线粒体肿胀、嵴断裂、甚至空泡化等超微结构变化。结果表明,钼镉及其联合均可引起机体发生氧化应激,降低机体抗氧化能力,并激活线粒体介导的凋亡通路,从而导致脾脏组织的氧化损伤,并且钼和镉具有协同效应。

To investigate the co-induced effects of molybdenum(Mo) and cadmium(Cd) on antioxidant indexes and apoptosis-related genes expression in duck spleens.120 healthy 11-day-old ducks with similar body weight were randomly divided into six groups with 20 ducks in each group,and ducks in each group were fed with basal diet with different concentrations of Mo or/and Cd:control group(0 mg/kg Mo,0 mg/kg Cd),low dietary of Mo group(15 mg/kg Mo),high dietary of Mo group(100 mg/kg Mo),Cd group(4 mg/kg Cd),low dietary of Mo combined Cd group(LMoCd,15 mg/kg Mo,4 mg/kg Cd) and high dietary of Mo combined Cd group(HMoCd,100 mg/kg Mo,4 mg/kg Cd).(NH4)6Mo7O24·4 H2O and 3 CdSO4·8 H2O were used as sources of Mo and Cd,respectively,and the test period lasted 60 days.On 30th and 60th day,10 ducks were randomly selected from each group,blood and spleen tissues were collected to detect serum antioxidant indexes,CP and apoptosis-related genes mRNA expression levels in spleen and the ultrastructure of spleen tissue was observed.The results showed that,on 30th day,the MDA content in combination groups was significantly higher than that in control group(P<0.05);the T-AOC in HMoCd group was significantly decreased compared to other groups(P<0.05);the XOD activity in treatment groups except LMo group was dramatically decreased compared to control group(P<0.05).On 60 th day,the activity of SOD and T-AOC had a downward trend in treatment groups,and they were significant decrease in combination groups compared to other groups(P<0.05 or P<0.01);the XOD activity in treatment groups except LMo group was significantly lower than that in control group(P<0.05);the NOS,CAT activities and MDA content had a upward trend,and they were significant increase in combination groups compared to other groups(P<0.05);On 60 th day,compared to control group,the mRNA expression level of CP was remarkably decreased in treament groups expect LMo group(P<0.05),while the mRNA expression level of Bak-1 was significantly higher than that in control group(P<0.01),and it was dramatically increased in combination groups compared to single groups(P<0.01);the Caspase-3 mRNA expression was higher than that in control and single groups(P<0.01);and the Bcl-2 mRNA expression was not significantly different among the groups(P>0.05).In treatment groups,ultrastructural changes showed that deformation and pyknosis of nucleus,swelling,rupture and vacuolization of mitochondria.The study indicated that Mo or/and Cd could cause oxidative stress,which leaded to decrease antioxidant capacity and activated the mitochondria-mediated apoptotic pathway,resulted in oxidative damage of spleen tissue,meanwhile,it showed a possible synergistic relationship between the two elements.