急性热应激对西伯利亚鲟HSP70 mRNA表达、血清皮质醇和非特异性免疫的影响

EFFECTS OF ACUTE THERMAL STRESS ON HSP70 MRNA,PHYSIOLOGY AND NONSPECIFIC IMMUNITY IN SIBERIAN STURGEON (ACIPENSER BAERII)

为研究西伯利亚鲟(Acipenser baerii)对急性热应激的抗逆机理,将体质量为(155.47±19.50)g的鱼从17.5℃迅速转至27.5℃水中,在1h和3h取样测定HSP70 mRNA表达变化、血清皮质醇和非特异性免疫指标。结果显示:急性热应激时鳃、脾和脑的HSP70 mRNA表达量升高,具有组织特异性,热应激1h时鳃的表达量升高最快(P<0.05),3h时保持1h时的表达水平;脾和脑热应激1h时表达量变化不显著,在1h至3h时升高较快,并且脑组织的表达量升高最快(P<0.05)。热应激1h时血清皮质醇(Cortisol)含量迅速升高(P<0.05),之后快速回落。脾脏巨噬细胞呼吸暴发在热应激1h时显著升高(P<0.05),3h时降低。血清补体C3在1h时略有升高,3h时显著性降低(P<0.05)。血清溶菌酶活性(LZM activity)先升高后降低差异不显著。血清超氧化物歧化酶(SOD)活力随热应激时间延长逐渐降低,3h时显著降低(P<0.05)。血清丙二醛(MDA)含量随热应激时间延长逐渐降低,差异不显著。以上结果表明:1h的短暂急性应激增强了西伯利亚鲟的非特异性免疫,3h的应激使免疫力和抗氧化能力显著下降;在热应激过程中,HSP70表达升高,其中鳃组织最快,起到应激保护作用,提高了机体热耐受力。

The effect of acute thermal stress on HSP70 mRNA expression,physiology and nonspecific immunity were investigated in Siberian sturgeon.In the experiment,ten fish were transferred from17.5℃ to 27.5℃ water,then data were measured at 1h and 3h.Fish in 17.5℃ water were taken as 0h group.Respiratory rate increased from 80—90 breaths/min to 210 breaths/min,then decreased to 180 breaths/min after 0.5h.Among the three tissues including gill,spleen and brain,the HSP70 mRNA expression in gill rose most quickly after 1h stress,and was about 1.63 fold compared with the 0h group（P0.05）,then remained this level to 3h;The HSP70 mRNA expression in spleen and brain had nearly no change in 1h thermal stress,then rose quickly from 1h to 3h in the two tissues,especially in brain at 3h rose most quickly to about 1.77 fold compared with the 1h group（P0.05）.Compared with the 0h group,serum cortisol increased quickly and was 5.14 fold（P0.05） at 1h,then decreased quickly to 2.1 fold at 3h.Spleen macrophage respiratory burst achieved the maximum（P0.05） at 1h,then reduced to the 0h group level.Serum complement C3 increased at 1h and decreased significantly at 3h（P0.05）.Serum lysozyme activity firstly elevated then decreased but had no significant differences.Serum SOD activity decreased when thermal stress time prolonged,and achieved the minimum at 3h（P0.05）.Serum MDA content decreased when thermal stress time prolonged and had no significant difference.The results showed that 1h acute thermal stress promoted the nonspecific immunity and tolerance,but 3h acute thermal stress decreased it.