亚硝酸氮胁迫对刺参体壁非特异性免疫能力及HSP70表达的影响

Effect of Nitrite Stress on the Non-Specific Immune Response and HSP70 Expression of Sea Cucumber Apostichopus japonicus

在实验室条件下，研究了慢性亚硝酸氮胁迫对刺参（Apostichopusjaponicus）（湿重（48．96±0．88）g）体壁非特异性免疫能力及热休克蛋白（HSP70）表达的影响。结果表明，刺参在0．12±57．50mg／L亚硝酸氮胁迫下，体壁中酸性磷酸酶（ACP）、碱性磷酸酶（AKP）、总抗氧化能力（T-AOC）及溶菌酶（LSZ）活性均在胁迫初期显著升高。到第20天时，57．50mg／L亚硝酸氮胁迫组刺参体壁中ACP、AKP和LSZ活性以及T-AOC均显著低于对照组。低浓度亚硝酸氮（0．12和2．30mg／L）胁迫能够显著提高刺参体壁超氧化物歧化酶（SOD）、过氧化氢酶（CAT）的活性。而高浓度亚硝酸氮（11．50和57．50mg／L）胁迫则显著抑制刺参体壁SOD和CAT的活性。刺参体壁中微量丙二醛（MDA）含量随亚硝酸氮胁迫浓度的升高而升高，且随胁迫时间的延长在体壁中的积累量增大。刺参体壁中热休克蛋白70（HSP70）的表达量在亚硝酸氮胁迫初期迅速升高至最高，但随胁迫时间的延长而降低并趋于稳定，其最大表达量与亚硝酸氮浓度呈显著对数相关关系。研究表明，刺参在低于2．30mg／L亚硝酸氮胁迫下，体内非特异性免疫酶能主动发挥作用；但在较高浓度亚硝酸氮胁迫下，体内非特异性免疫能力显著下降，且刺参体壁中MDA含量和HSP70的表达量可以较好的反映刺参受亚硝酸氮胁迫的程度。

The effect of ambient nitrite at different concentrations on the non-specific immune response and HSP70 expression of the body wall of sea cucumber （Apostichopusjaponicus） （mean weight 48. 96±0. 88 g） was studied through experimental ecological approach. The results showed that, 1） after being treated with nitrite at concentrations ranging from 0. 12 to 2.30 mg/L, the acid phosphatase （ACP） activi-ty, alkaline phosphates （AKP）, total antioxidant capacity （T-AOC） and lysozyme （LSZ） activity of the body wall of sea cucumber peaked at beginning. When exposed to chronic nitrite （57. 50 mg/L） for 20 days, ACP, AKP, SOD and LSZ of the body wall were all significantly lower than those of control （P〈0.05） ; 2） the superoxide dismutase （SOD） and catalase （CAT） activity of sea cucumber increased signifi-cantly at low nitrite concentrations ranging from 0. 12 to 2.30 mg/L; however, such activity decreased sig-nificantly at high concentrations ranging from 11.50 to 57.50 mg/L （P〈0.05） ; 3） with the time exten- sion and concentration increasing, the content of malondialdehyde （MDA） in the body wall of sea cucum-ber increased significantly （P〈0.05）; and 4） the expression of heat stress protein 70 （HSP70） peaked at beginning, and then decreased gradually to a steady level. The maximum expression of HSP70 gene was positively correlated with the concentration of ambient nitrite in sea cucumber body wall （P〈0. 05）. The results indicated that the immunoenzymes of sea cucumber were slightly affected by low concentrations （〈 2.30 mg/L） ; but significantly by high concentrations. MDA content and HSP70 expression in the body wall of sea cucumber may aid to the identification of nitrite stress to sea cucumber.