氨和空气暴露对大鳞副泥鳅肝脏抗氧化能力的影响

将大鳞副泥鳅(Paramisgurnus dabryanus)分别暴露于 30 mmol/L NH₄Cl 溶液和空气中, 以评价氨和空气暴露对其肝脏抗氧化能力的影响。结果显示, 氨暴露并未引起大鳞副泥鳅肝脏超氧化物歧化酶(superoxide dismutase, SOD)活性的显著变化, 仅空气暴露 12 h 后, 大鳞副泥鳅肝脏 SOD 活性显著高于对照组(P<0.05)。氨和空气暴露均显著降低了大鳞副泥鳅肝脏过氧化氢酶 (catalase, CAT) 活性 , 且在暴露 72 h 后升高 (P<0.05) 。丙二醛 (malondialdehyde, MDA)及脂质过氧化物(lipid peroxide, LPO)含量在氨和空气暴露组中均呈现先显著上升后下降的趋势。氨和空气暴露对大鳞副泥鳅肝脏谷胱甘肽-S 转移酶(glutathione S-transferase, GST)活性、谷胱甘肽(glutathione, GSH)含量和总抗氧化能力(total antioxidant capacity, T-AOC)无显著影响(P>0.05), 但谷胱甘肽过氧化物酶 (glutathione peroxidase, GSH-Px)活性均明显降低, 乙酰胆碱酯酶(acetylcholin esterase, AChE)活性均显著上升。综上所述, 在氨和空气暴露的初期, 大鳞副泥鳅体内出现了明显的氧化反应; 而在暴露一段时间后, 体内的氧化反应受到了明显的抑制, 大鳞副泥鳅肝脏中 SOD、CAT、GST 及 GSH-Px 等抗氧化酶系统并未被成功激活。

Effects of ammonia and aerial exposure on the hepatic antioxidant capacity of Paramisgurnus dabryanus

Paramisgurnus dabryanus were exposed to 30 mmol/L NH₄Cl solution and air to evaluate the effects of exogenous and endogenous ammonia accumulation on the hepatic antioxidant capacity of this species. During various periods of ammonia exposure, hepatic superoxide dismutase (SOD) activity fluctuated slightly but was not significantly different from the control group (P>0.05). Only after 12 h of air exposure, the SOD activity was notably higher than in control group (P<0.05). Both ammonia and aerial exposure markedly decreased catalase (CAT) activity. The malondialdehyde and lipid peroxide contents first increased and then fell after ammonia and air exposure. The hepatic glutathione S-transferase (GST) activity, glutathione contents, and total antioxidant capacity were unaffected by ammonia and aerial exposure, while the glutathione peroxidase (GSH-Px) activity significantly decreased and the acetylcholinesterase activity markedly increased (P<0.05). Our results indicated that obvious oxidation reactions occurred during the early stage of ammonia and aerial exposure in P. dabryanus, while these reactions were inhibited after a period of exposure. However, the antioxidant enzyme system (e.g. SOD, CAT, GST, and GSH-Px) in P. dabryanus was not activated successfully.