摄入异烟肼对家蚕幼虫体内谷胱甘肽氧化还原循环和谷胱甘肽S-转移酶活性的影响

为了建立家蚕Bombyx mori的药物筛选和毒性评价模型， 以剂量为2 000 mg/kg的抗结核模药异烟肼饲喂家蚕5龄第3天幼虫后检测其中肠和脂肪体的抗氧化解毒相关代谢的变化。结果表明： 雌蚕中肠组织中， 总谷胱甘肽(GSH+2GSSG)、 还原型谷胱甘肽(reduced glutathione, GSH)和氧化型谷胱甘肽(oxidized glutathione, GSSG)含量均呈现迅速上升再缓慢下降趋势； 谷胱甘肽S 转移酶(glutathione S-transferase, GST)活性升高到较大值后逐渐降低； GSH/GSSG的比值下降表明， 在72 min后中肠组织向氧化态转移。脂肪体组织中， 总谷胱甘肽、 GSH和GSSG含量变化均呈现迅速下降再迅速上升的趋势； GST活性达到最大值后逐渐降低后趋于平稳； GSH/GSSG比值升高表明， 在72 min后脂肪体组织向还原态转移。无论雌蚕还是雄蚕， 总谷胱甘肽、 GSH和GSSG含量以及GST活性均是脂肪体高于中肠。雌蚕的总谷胱甘肽含量、 GSH和GSSG含量高于雄蚕， 但雄蚕的GST活性高于雌性。结果说明， 摄入异烟肼引起了家蚕幼虫体内谷胱甘肽氧化还原状态的改变和酶活性的变化， 在这个过程中脂肪体起主要解毒代谢作用。

Effects of isoniazid intake on the glutathione redox cycle and glutathione S-transferase activity in larvae of the silkworm,Bombyx mori

In order to construct a model of drug screening and toxicity evaluation in the silkworm, Bombyx mori, the metabolisms related to antioxidation and detoxification in the midgut and fat body in the 3-day-old 5th instar larvae of the silkworm fed with isoniazid, an anti tuberculosis model drug, at a dose of 2 000 mg/kg were investigated. The results indicated that in the midgut of female silkworms, the contents of total glutathione (GSH+2GSSG), glutathione (GSH) and oxidized glutathione (GSSG) increased rapidly first and then decreased slowly. The glutathione S transferase (GST) activity also increased to a higher level first and then dropped gradually to a steady level. The decline of the GSH/GSSG ratio in the midgut of female silkworms indicated the oxidative shift of redox status at 72 min after treatment. In the fat body of female silkworms, however, the contents of total glutathione, GSH and GSSG dropped rapidly first and then increased quickly, while the GST activity fell gradually and then increased to a peak. The increase of the GSH/GSSG ratio in the fat body revealed the reduced shift of redox status at 72 min after treatment. In both female and male silkworms the contents of total glutathione, GSH and GSSG, and the GST activity were higher in the fat body than in the midgut. The contents of total glutathione, GSH and GSSG were higher in females than in males, whereas the GST activity was higher in males than in females. The results suggest that the intake of isoniazid resulted in the change of the glutathione redox status and the related enzyme activities in larvae of the silkworm, and fat body plays a major role in the process of detoxification.