动物双歧杆菌V9亚慢性毒性研究

Subchronic toxicity of Bifidobacterium animalis V9 in rats

目的研究动物双歧杆菌V9的亚慢性毒性,提出其无可见有害作用水平(NOAEL)。方法 80只断乳SD大鼠按体重随机分成4组,即对照组和3个受试物组,每组20只,雌雄各半。低、中、高剂量分别为1.25、2.50、5.00 g/kg BW。各剂量组灌胃给予受试物,对照组灌同体积的蒸馏水。动物单笼喂养,自由饮食,每周记录大鼠进食量,每周称2次体重以调整灌胃量,连续观察90 d,于实验中期(46 d)和实验结束采血测各项血液学和临床生化指标,并进行病理组织学检查。结果各受试物剂量组动物体重、进食量、食物利用率、临床生化指标、各脏器脏体比与对照组比较均无显著性差异;病理指标也未见由受试物引起的异常改变。血常规指标中有显著性差异的检测值均在本室历史正常对照检测范围内,无生物学意义。结论根据本次实验结果确定动物双歧杆菌V9 NOAEL在雌雄大鼠均为5.00 g/kg BW,即本实验的高剂量,相当于人体推荐量的300倍。

Objective To study the subchronic toxicity of Bifidobacterium animalis V9, and to determine its no- observable-adverse-effect-level （NOAEL）. Methods Eighty Sprague-Dawley rats were randomly divided into four groups, twenty rats （10 males and 10 females） per group. Animals in the three treatment groups were given 1.25, 2.50, and 5.00 g/kg BW of test material by gavage for 90 days respectively, and rats in the control group were treated with the same volume of water by gavage for 90 days. Clinical observations were conducted daily. Body weights and food consumption were recorded weekly. Blood samples were collected from all rats on the Day 46 and at the termination of the study, and gross examinations were performed on all animals euthanized for necropsy. Organ weights were recorded and selected tissues were examined microscopically. Results All parameters including body weight, food consumption, clinical biochemistry, absolute and relative organ weights and histopathology in treatment groups had comparable values to animals in the control group. Differences on hematology between treated and control groups were not treatment-related. Conclusion The NOAEL of B. animalis V9 were 5.00 g/kg BW in male and female rats, which was the highest dosage tested in this study, was equivalent to 300 times of the dosage recommended for human use.