SO2对家蚕血淋巴中谷胱甘肽含量及相关酶活性的影响

通过分析在SO2胁迫下家蚕5龄幼虫血淋巴中谷胱甘肽(GSH)含量及相关酶活性的变化,探讨SO2对家蚕的毒理作用机制。当对家蚕5龄幼虫每天以40 mg/m3SO2熏气刺激6 h,蚕体血淋巴中的GSH含量显著降低,雄蚕GSH的平均含量为49.8μmol/L,雌蚕为41.0μmol/L,分别为对照的73.80%和55.76%,而谷胱甘肽硫-转移酶(GST)活性显著升高,雄蚕GST的平均活性为31.86 U/L,雌蚕为31.80 U/L,分别高于对照46.15%和27.30%。与此同时,γ-谷氨酰转肽酶(γ-GT)活性在蚕体中也有不同程度的升高,其中在雄蚕体内的变化极为显著;谷胱甘肽过氧化酶(GSH-Px)和谷胱甘肽合成酶系的活性在蚕体内均无显著变化。以上结果表明:SO2刺激可对家蚕血淋巴中的GSH含量及其相关酶的活性产生影响,且雌、雄蚕对SO2的敏感性不同;GSH含量的减少及其相关酶活性的上升,说明SO2对蚕体的毒害作用与其降低蚕体抗氧化物质水平、削弱抗氧化防御系统有关。

Effects of SO2 Stress on Glutathione Content and Activities of Related Enzymes in Hemolymph of Silkworm

Through analyzing the changes of glutathione(GSH) content and activities of related enzymes in hemolymph of the 5th instar silkworm larvae under SO2 stress,the toxication mechanism of SO2 to silkworm was investigated.After the larvae were fumigated with SO2 at a dosage of 40 mg/m3 for 6 h each day,GSH content in hemolymph of the larvae decreased significantly.The mean content of GSH in male larvae was 49.8 μmol/L and that in female larvae was 41.0 μmol/L,being 73.80% and 55.76% of those in the control larvae,respectively.However,the activities of glutathione S-transferase(GST) increased remarkably.The mean activity of GST in male larvae was 31.86 U/L and that in female larvae was 31.80 U/L,being 46.15% and 27.30% higher than those in the control larvae,respectively.Meanwhile,activity of γ-glutamyl transpeptidase(γ-GT) in the larvae increased in various degrees,with extremely significant increase in male larvae.The activities of glutathione peroxidase(GSH-Px) and glutathione synthetase in both male and female larvae had no apparent changes.The above results showed that the content of GSH and the activities of related enzymes in hemolymph of silkworm were changed by stimulation with SO2,and the sensitivities on SO2 were different between female and male larvae.The decrease of GSH content and increase of activities of related enzymes showed that the effects of SO2 can be related to decreasing the level of antioxidant and impairing the antioxidation defense system in silkworm.