蓖麻蚕对蓖麻毒素的代谢解毒作用  

Metabolic Detoxification of Ricin by Castor Silkworm

作　　者：吴淑倩 韦红显 卢芙萍[3] 武华周 娄德钊 耿涛 王树昌[3] Wu Shuqian;Wei Hongxian;Lu Fuping;Wu Huazhou;Lou Dezhao;Geng Tao;Wang Shuchang(College of Ecology and Environment,Hainan University,Haikou 570228,China;College of Plant Protection,Hainan University,Haikou 570228,China;Environment and Plant Protection Institute,Chinese Academy of Tropical Agricultural Sciences,Haikou 571101,China)

机构地区：[1]海南大学生态与环境学院,海口570228 [2]海南大学植物保护学院,海口570228 [3]中国热带农业科学院环境与植物保护研究所,海口571101

出　　处：《蚕业科学》2023年第4期324-332,共9页ACTA SERICOLOGICA SINICA

基　　金：财政部和农业农村部国家现代农业产业技术体系项目;中央级公益性科研院所基本科研业务费专项(163004-2022016)。

摘　　要：蓖麻蚕及蚕蛹是食用、饲用的优质蛋白质来源,但蓖麻蚕体内蓖麻毒素残留量及代谢解毒作用机制尚不明确,严重限制其食品化、饲料化开发应用。为解析蓖麻毒素在蓖麻蚕体内的代谢解毒机制,对蓖麻蚕5龄幼虫添饲或注射蓖麻毒素,分析蓖麻蚕对蓖麻毒素的吸收率、注射毒素致死中量、毒素代谢降解率,检测GST-GSH-Px解毒体系酶活性变化,并分析添饲谷胱甘肽(GSH)对蓖麻蚕存活率的影响。试验结果表明,蓖麻蚕对蓖麻毒素的吸收率约为0.12%,大部分毒素随蚕沙排出体外。蓖麻蚕全龄添饲毒素原液(2.319 mg/mL)并未死亡,但注射致死中量LD50为13.90 ng/g。添饲蓖麻毒素后,1~5龄幼虫、蚕蛹、5龄蚕血淋巴和中肠中的蓖麻毒素含量极低(0.32~0.59 ng/g);添饲毒素后幼虫对毒素的降解率达99.99%,而注射毒素幼虫对毒素的降解率为97.57%。进一步分析表明,蓖麻蚕添饲毒素后全蚕、血淋巴和中肠中GSH含量以及GR、GST、GSH-Px酶活性均显著提高;注射毒素后,全蚕和血淋巴中GSH含量先降后升,而GR、GST、GSH-Px酶活性则显著上调,中肠中GR、GST、GSH-Px酶活性呈上调趋势,但增幅比血淋巴更小,说明血淋巴和中肠是主要解毒组织,依赖GST-GSH-Px解毒防御体系完成毒素代谢;注射GSH能够延长幼虫致死中时(LT50)18.52 h,进一步确认GST-GSH-Px解毒防御体系在蓖麻毒素代谢降解中的作用。研究结果明确蓖麻蚕及蚕蛹体内蓖麻毒素含量极低,蓖麻蚕依赖血淋巴和中肠中的GST-GSH-Px解毒防御体系降解体内蓖麻毒素。上述结果为蓖麻蚕及蚕蛹的食用化、饲料化安全评价以及蓖麻蚕毒素解毒药物的研发提供了科学依据。The larva and pupa of castor silkworm(Philosamia cynthia ricini)are high⁃quality protein sources for food and feeding.However,the residual amount of ricin and the mechanism of detoxification and metabolism are still unclear,which seriously limits their development and application in food and feed.In order to analyze the metabolic detoxification mechanism of ricin in the body of castor silkworm,the 5th instar larvae of castor silkworm were fed or injected with ricin.The absorption rate of ricin,the half lethal dose and the metabolic degradation rate of ricin were analyzed.The change of enzyme activity of GST⁃GSH⁃Px system was detected,and the effect of injecting glutathione(GSH)on the survival rate of castor silkworm was analyzed.The results showed that the absorption rate of ricin by castor silkworm was about 0.12%,thus most of the toxin was excreted with silkworm excrement.The castor silkworm did not die when fed with the toxin stock solution(2.319 mg/mL)at the whole larva instar,but the LD50 after injecting with ricin was 13.90 ng/g.After feeding with ricin,the contents of ricin in the 1st to 5th instar larvae,pupa,and the hemolymph and midgut of the 5th instar larvae were ex⁃tremely low(0.32-0.59 ng/g).The degradation rate of ricin in the larvae fed with ricin was 99.99%,while that in the lar⁃vae injected with ricin was 97.57%.Further analysis showed that after feeding with ricin,GSH content and GR,GST,and GSH⁃Px activity in the whole body,hemolymph and midgut were all significantly up⁃regulated.After the injection of ri⁃cin,the contents of GSH in the whole body and hemolymph decreased first and then increased,while the activity of GR,GST,and GSH⁃Px enzymes were significantly up⁃regulated.In addition,the activity of GR,GST,and GSH⁃Px enzymes in the midgut showed an up⁃regulation trend,but the increase was smaller than that in the hemolymph,indicating that the hemolymph and midgut were the main detoxification tissues,relying on GST⁃GSH⁃Px detoxification defense system to complete the

关 键 词：蓖麻蚕 蓖麻毒素 代谢 解毒 还原型谷胱甘肽 

分 类 号：S885.2[农业科学—特种经济动物饲养]