Varying Dietary Levels of Molybdenum Inducing Cell Apoptosis of Spleen Under Cadmium Stress in Caprine.

Abstract

The present experiment aims at evaluating chronic toxic effects of the combination of cadmium (Cd) and molybdenum (Mo) according to residual element contents, apoptosis gene expression, and ultrastructure and histopathology changes of caprine spleen. In total, 36 Boer goats were randomly divided into four groups with the equal number in each group. The control group was orally administered with deionized water while the experimental groups I, II, and III were administered with the equal quantity of CdCl2 (1mgkg(-1) BW) and (NH4)6·Mo7O24·4H2O including 15, 30, and 45mg·Mokg(-1) BW, respectively. Three individuals from each group were treated with euthanasia on days 0, 25, and 50. The data showed that the content of splenic residual Mo and Cd increased (P<0.05) in the experimental groups on days 25 and 50, while no significant difference was observed in the content of Cu. The apoptosis-related gene expression levels including Bcl-2, Bax, Caspase-3, Smac, and ceruloplasmin (CP) were also determined. Results showed that significant reductions were observed in Bcl-2 and CP expressions (P<0.01), while Caspase-3 gene was up-regulated (P<0.05). However, no significant difference was observed in Smac and Bax expressions. Furthermore, on day 50, spleen tissues were presented to observe ultrastructural changes in lesions by means of transmission electron microscopy, with fragmentized nucleus, vesiculation of cytoplasm, mitochondria hyperplasia, and increasing lysosomes included. In addition, histopathology results corroborated the toxicity by showing cell hemorrhage, thickening central arteries, and enhanced capsule thickness. To sum up, our study revealed that the combination of Cd and Mo could induce remarkable damage to the spleen of goats by promoting cell apoptosis in the mitochondrial pathway and affecting the deposition of Mo and Cd.