【作者】 洪美玲； 陈立侨； 孙新谨； 李二超； 顾顺樟； 禹娜；

【Author】 HONG Mei-ling1,2,CHEN Li-qiao~*1,SUN Xin-jin1,LI Er-chao1,GU Shun-zhang1,YU Na1 (1.School of life science,East China Normal University,Shanghai,200062,China; 2.School of life science,Hainan Normal University,Haikou,571158,China)

【机构】 华东师范大学生命科学学院； 海南师范大学生命科学学院；

【摘要】 为探讨亚硝酸盐急性胁迫对中华绒螫蟹机体免疫力的影响,以及机体在胁迫过程中的应对策略,本研究分别测定了幼蟹(平均体重3.25g)在10-、20-、30-、40-mg/l亚硝酸盐暴露组和对照组中血细胞总数(THC)、超氧化物歧化酶(SOD)活力、丙二醛(MDA)含量以及热休克蛋白70(HSP70)表达量在受胁2d内的动态变化。研究结果表明:(1)10-mg/l亚硝酸盐胁迫组的THC在应激3h时显著高于对照组,肝胰腺中SOD活性在应激3h和6h时亦显著提高,表明低浓度的亚硝酸盐暴露在短期内均可使中华绒螯蟹幼体的血细胞数显著增多,肝胰腺SOD活性显著升高,表现出一定的"毒物兴奋效应"(poison-intoxication effect)。40-mg/l亚硝酸盐暴露使幼蟹血细胞数减少,肝胰腺SOD活性下降,提示机体对超氧阴离子的清除能力下降,从而在一定程度上降低了机体的免疫力。当亚硝酸盐的暴露浓度在20-和30-mg/l时,THC显著低于对照组,且暴露浓度越高THC的下降幅度越大,但肝胰腺SOD活性变化不明显,仅30-mg/l亚硝酸盐暴露组在应激2d时其SOD活性显著低于对照组。(2)肝胰腺中MDA含量随暴露浓度的升高而升高,且随暴露时间的延长在组织中的累积量增大,说明亚硝酸盐暴露使组织中脂质过氧化程度加剧。(3)未经任何处理的对照组中也有少量的HSP70表达。中华绒螯蟹幼体经10-和20-mg/l亚硝酸盐处理后,鳃组织中HSP70的表达量在应激6h后达到最大,而经30-和40-mg/l亚硝酸盐处理后,HSP70的表达量在应激3h后达到最大。各浓度组所诱导的HSP70的最大表达量与水中亚硝酸盐的浓度呈正相关。以上结果说明亚硝酸盐的胁迫是通过加剧组织中脂质过氧化的方式而导致机体的免疫力下降,肝胰腺中MDA的含量变化可作为亚硝酸盐胁迫的有效评价指标之一,而HSP70表达量的变化可作为早期的预警指标应用于亚硝酸盐胁迫的评价中。更多还原

【Abstract】 Nitrite is an intermediate product either in the bacterial nitrification of ammonia,or a product in the bacterial denitrification of nitrate.Intensive aquacultural practices,where overcrowding and poor water re-circulation are commonplace,the concentration of nitrite may reach 50 mg/l in recireulated culture systems due to an imbalance in biofilters.High levels of nitrite in water are potential factors triggering stress in aquatic organisms.So in this study,in order to investigate the effect of ambient nitrite on the immunity response of the Chinese mitten-hand crab E.sinensis and select the sensitive indicators of stress evaluation, the juvenile crabs(mean weight:3.25g) were submitted to four nitrite exposed groups(10-,20-,30-and 40-mg/l ambient nitrite concentrations) and control group.The total hemocyte counts(THC),superoxide dismutase(SOD) activity,malodiadehyde(MDA) level and HSP70 expression was measured at 3h-,6h-,1d-, and 2d-stress period.The results have showed as follows:(1).After 10-mg/l nitrite exposure,THC increased significantly at 3h-stress and SOD activity in hepatopancreas increased significantly at 3h-and 6h-stress compared with the control,which indicated nitrite exposure of low concentration could increase THC and SOD activity in E.sinensis juveniles and exhibited the poison-intoxication-effect.After 40-mg/l nitrite exposed,the trend of the THC and SOD activity were inversed.While nitrite exposure concentrations were 20-and 30-mg/l,THC was lower than that in control and decreased with ambient nitrite increased,however, the change of SOD activity was not obvious except 30-mg/l nitrite exposure group at 2d-stress..............更多还原