铅暴露与排放对中华鲟幼鱼血液中ALT、AST活力的影响

采用水溶液静态置换法,从中华鲟(Acipenser sinensis)受精卵发育至96 h开始,研究了其在0(对照组)、0.2、0.8和1.6mg·L~(-1) Pb~(2+)水溶液中暴露16周,随后排放6周,对中华鲟幼鱼血液中ALT、AST活力的影响.结果显示:Pb暴露后幼鱼血液中的ALT和AST活力均表现为随Pb暴露剂量增加而升高的趋势,1.6mg·L~(-1)组ALT活力与其它各组比较呈极显著差异(P<0.01);0.8和1.6mg·L~(-1)组AST活力与对照组比较分别呈显著差异(P<0.05)和极显著差异(P<0.01). Pb排放后,各暴露组血液中ALT活力降低至对照组水平(P>0.05);1.6 mg·L~(-1)组的AST活力依然较高.超出对照组近2倍(P<0.01).对照组血液的AST/ALT值在2.24～2.32之间;随Pb质量浓度增加,暴露后AST/ALT值呈增加趋势.Pb排放后AST/ALT值降低,但1.6 mg·L~(-1)组与其余各组比较仍维持较高值(P<0.05).初步认为,0.2 mg·L~(-1)和0.8 mg·L~(-1) Pb~(2+)暴露导致中华鲟幼鱼肝细胞不同程度受损,经Pb排放后,轻度受损的组织细胞能够恢复.血液中的AST/ALT值在判断鱼类组织损伤中也具有重要意义.

Effects of lead on activity of ALT and AST in serum of juvenile Chinese sturgeon, Acipenser sinensis

The disruption of Alanine amiotransferase (ALT) and Aspartate aminotransferase (AST) activity in serum of juvenile Chinese sturgeon (Acipenser sinensis) caused by chronic waterborne Pb was demonstrated in the present study. Fish (from 96 hours developed zygotes to juvenile) were exposed to 0 mg·L~(-1) (control), 0.2 mg·L~(-1), 0.8 mg·L~(-1) and 1.6 mg·L~(-1) Pb~(2+) for 16 weeks and then transferred to Pb-free water for 6 weeks. Results showed that, after long term lead exposure, ALT and AST activity presented a up-ward trend with the increasing Pb concentrations. Significant increase of ALT activity was only found in 1.6 mg·L~(-1) group (P<0.01) while significant increase of AST activity was found both in 0.8 mg·L~(-1) group (P<0.05) and1.6 mg·L~(-1) group (P<0.01). After de-puration in clean water for 6 weeks, ALT activity of juveniles exposed to all lead groups decreased to the level of control group(P>0.05), however, the activity of AST was still high, almost twice higher than control when exposed in the concentration of 1.6 mg·L~(-1) Pb~(2+). AST: ALT ratio of control group was from 2.24 to 2.32. After Pb exposure, ALT: AST ratio presented a upward trend with in-creasing Pb concentrations. After Pb depuration, AST: ALT ratio decreased, however, the ratio in 1.6 mg·L~(-1) group was still higher than control group(P<0.05). It was considered that after exposure in 0.2 mg·L~(-1) or 0.8 mg·L~(-1) Pb~(2+) concentration, liver of juvenile Chinese sturgeon maybe impaired in different degrees and slight damage could be repaired after depurated in clean water. AST: ALT ratio was also important for evaluating the impairment of fish tissue.