Roles of zinc and selenium in protecting sea cucumber Apostichopus japonicus coelomocytes against lipopolysaccharide-induced oxidative stress in vitro

This study investigated the attenuate effects of zinc (Zn) and selenium (Se) on lipopolysaccharide (LPS)-induced oxidative stress in sea cucumber Apostichopus japonicus coelomocytes in vitro. Coelomocytes were first treated with different concentrations of Zn (0.12, 0.48 and 1.2 mM) and Se (0.06, 0.24 and 0.6 mM) for 12 h and the optimal concentrations of Zn and Se as antioxidants for A. japonicus coelomocytes were selected based on antioxidant parameters including total antioxidant capacity (T-AOC) and activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and concentration of reduced glutathione (GSH). Next, coelomocytes were pretreated with 0 (control), 0.12 mM Zn or 0.24 mM Se for 12 h, and then were treated with LPS (100 mu g mL(-1)) for 6 h. Se completely inhibited LPS-induced increase in superoxide anion (O-2(-)) production and lipid peroxidation (LPO) and effectively prevented the LPS-induced decreases of T-AOC, activities of SOD, CAT, GPx and GST and concentration of GSH. Zn alleviated the LPS-induced oxidative stress but the protective effects were not as effective as Se. The present work also proved that suboptimal amount of Zn and Se could impair the antioxidant system of A. japonicus coelomoytes. In conclusion, the present work demonstrated that both Zn and Se, especially Se, have the potentials to be the effective antioxidants for A. japonicus. Further work will be conducted for their optimal administration concentrations in vivo.