荚膜甲基球菌蛋白遗传毒性研究和被动皮肤过敏试验

Genetic Toxicity Study and Passive Cutaneous Anaphylaxis Test of Methylococcus Capsulatus Bacteria Meal

荚膜甲基球菌蛋白(Methylococcus capsulatus bacteria meal,MBM)拟开发为新饲料原料。本研究旨在通过遗传毒性研究和被动过敏试验评价其毒理学安全性,为其未来的应用奠定基础。本研究包括四个试验:鼠伤寒沙门氏菌回复突变(Ames)试验采用平板掺入法,每皿剂量在0.625~10.000 mg范围内,采用TA97、TA98、TA100、TA102和TA1535五种菌株进行回复突变试验;小鼠骨髓细胞微核试验和精子畸形试验均设2500、5000、10000 mg/kg三个MBM剂量组,微核试验采用30 h两次给药法,精子畸形试验连续染毒5 d,分别在既定的时间采样制片;大鼠被动皮肤过敏试验设250、500、1000 mg/kg三个MBM剂量组,制备抗血清后背部皮内注射致敏,24 h和/或48 h后进行抗原激发,考察蓝色反应斑直径。所有试验均根据要求设置阴性、阳性对照组。结果表明:在有或无代谢活化系统结果(S9)时,MBM的鼠伤寒沙门氏菌回复突变(Ames)试验结果均为阴性;小鼠骨髓细胞微核和精子畸形试验结果均为阴性;大鼠皮肤被动过敏试验结果为阴性。说明在设置的试验系统和剂量下MBM未显示遗传毒性和潜在的致敏性。

Methylococcus capsulatus bacteria meal(MBM)is intended to be developed as a new feed ingredient.This study was aimed to evluate toxicological safety of MBM through genotoxicity study and passive cutaneous anaphylaxis test,which laying the foundation for its future applications.The Ames test was performed by the plate doping method with doses ranging from 0.625 to 10 mg per dish,reverse mutation test was carried out in five strains of TA97,TA98,TA100,TA102 and TA1535.The mice micronucleus test and the sperm malformation test both performed at 2500,5000,10000 mg/kg.The micronucleus test was conducted using a 30 h double administration method,and the sperm abnormality test was continuously exposed to the MBM for 5 days.Two tests were respectively sampled and produced smear at a predetermined time.The rat passive cutaneous anaphylaxis test was performed at 250,500,1000 mg/kg.The antiserum was prepared and then sensitization by Intradermal injection on the back.Antigenic challenge was performed 24 h and/or 48 h later.Finally the blue reaction spots were examined.Negative and positive control groups were set up for all tests.The results showed that the with or without metabolic activation system(S9),the Salmonella typhimurium reverse mutation assay(Ames test)result was negative;the mice bone marrow cell micronucleus and sperm abnormality test results were both negative;and the rat passive cutaneous anaphylaxis test result was negative.The study suggests that MBM showed no genotoxicity and potential allergy under the set test system and dose.