The Co-induced Effects Of Molybdenum And Cadmium On Oxidative Damage And Related Genes Expression In Duck Spleen

This study was aimed to investigate the co-induced effects of Molybdenum(Mo) and Cadmium(Cd) on antioxidant function and its related gene expression in duck spleens. 360 healthy eleven-day-old ducks were randomly divided into control group and experimental groups(ⅰ, ⅱ, ⅲ, ⅳ and ⅴ groups). Control group was fed the basal diet, experimental groups were treated with Per kilogram of basal diet containing different concentrations of Mo or/and Cd: ⅰ group(15 mg/kg Mo), ⅱ group(100 mg/kg Mo), ⅲ group(4 mg/kg Cd), ⅳ group(15 mg/kg Mo,4 mg/kg Cd) and ⅴ group(100 mg /kg Mo, 4 mg/kg Cd). Hexaammonium molybdate((NH4)6Mo7O24·4H2O), cadmium sulfate(3CdSO4·8H2O) were used as sources of Mo and Cd respectively. T The treatment lasted for 120 days. Wing venous blood and spleen tissues were collected immediately from ducks by random selection of 10 ducks from each group on days 30, 60, 90 and 120, respectively for determining white blood cells, relative weight of spleen, MDA content, activities of XOD, CAT and NOS, the mRNA expression levels of Bak-1, Bcl-2, Caspase-3, MT-1, CP, TNF-α, COX-2, NF-κB, histopathology examination and ultrastructural changes of spleen tissue. The results are as following:1. Compared with control group, relative weight of spleen were decreased(P<0.05) in the high dietary of Mo combined with Cd group;WBC in the blood were decreased in the high dietary of Mo combined with Cd group compared with control group and single Mo group(P<0.05) on 90 and 120 day.2. The content of MDA were significantly increased in co-treated Mo and Cd groups compared with other groups(P<0.01); the activity of NOS were significantly increased(P<0.01) and the activities of XOD and CAT were significantly decreased(P<0.01) in co-treated Mo and Cd groups compared with control group and the low dietary of Mo group.3. The spleen appeared histological lesion: congestion, bleeding, red pulp and white pulp boundary disappeared, sheath artery wall thicken obviously in co-treated Mo and Cd groups, and the degree of damage was greater than the single Mo and Cd groups.4. The spleen appeared ultrastructural changes: deformed nuclei, karyopyknosis, mitochondrial crest fracture and vacuolation, and the degree of damage was greater than the single Mo and Cd groups.5. The expression levels of Bak-1, Caspase-3, TNF-α, NF-κB, COX-2 and MT-1 were obviously increased(P<0.05 or P<0.01), while the expression levels of Bcl-2 and CP were obviously decreased(P<0.05 or P<0.01).Conclusion: Exposure to Mo or/and Cd might lead to inflammatory response, the expression levels of TNF-α, NF-κB, COX-2 were obviously increased, while they also could cause the acitivities of antioxidant enzymes decreased, and activating mitochondrial mediated apoptosis pathways, and eventually led to spleen injury. Interaction of Mo and Cd may have a synergistic effect on the spleen toxicity.