连续低剂量黄曲霉毒素B1对大鼠肝肾损伤作用

用含有不同质量浓度黄曲霉素B1（AFB1）（0、4、20、25、50μg／kg）的污染饲料连续饲喂各试验组大鼠60d，于7、15、30、60d静脉取血，测定各组大鼠肝功能与肾功能生化指标。每周检测大鼠体质量，试验第60天断头处死大鼠，检测肝肾组织病理学变化并计算各组大鼠的脏体系数。试验期间备组受试动物未发现明显的中毒症状和异常情况，60d内无受试动物死亡。与对照相比，不同剂量组AFB1对大鼠体质量无显著性影响；连续喂饲7d，大鼠血清AST和BuN含量显著升高（P〈0．05）；连续喂饲15d，大鼠血清AsT、BUN和ALB含量显著升高（P〈0．05），连续喂饲30d，大鼠血清BUN含量显著升高（P〈0．05），连续喂饲60d，大鼠血清CR和BUN含量显著升高（P〈0．05）。在各测试质量浓度条件下，大鼠虽未发现明显的中毒症状和异常情况，试验期间无动物死亡，但与空白对照相比，各剂量组AFBl对大鼠均产生了显著的肝肾组织病理学损伤，中毒程度与给毒剂量成正相关性。随着毒素暴露时间延长，大鼠肝脏对低剂量AFBl表现出一定的耐受性，而大鼠的肾脏损伤与毒素暴露时间表现出显著的积累效应。

Toxicological impacts on damage of liver and kidney in rats by successively administered low dose of aflatoxin B1

Aflatoxin BI（AFB1） is one of the most heavily polluted and dangerous mycotoxin for the product of cereals and oils. Different dose of AFB1 which referred to the maximum residue limits（MRL） for foods of main agricultural import and export countries were tested in rats continuously for 60 days, to evaluate sub-chronic poisoningat low dose of AFB1 exposure. Different concentrations of AFB1 （0,4,20,25 and 50 μg/kg） were applied to five groups, re- spectively, the physiological indicators of liver and kidney were determined at the time point of 7,15,30 and 60 days, the body weight were recorded every week,the pathological sections and ratio of organ and body were also examined at the end of the experiment. Poisoning symptoms or abnormal behaviors were not observed in all tested subjects, and no animals died in the trial period. There were no significant differences between the body weight of rats adminis- tered by different doses of AFB1 and the control subjects. At 7 days of continuous feeding,the serum levels of AST and BUN were significantly elevated （P~0.05） ;at 15 days, the serum levels of AST, BUN and ALB were signifi- cantly elevated （P〈0.05） ~at 30 days,the serum level of BUN was significantly elevated （P〈0.05） at 60 days,the serum levels of CR and BUN were significantly elevated （P〈0.05）. The different doses of AFB1 administered rats showed significant toxicity to the physical function of rat liver and kidney, and the degree of poisoning was positively correlated to the amount of AFB1 administered. The treated rat livers exhibited some degree of tolerance to the low doses of AFB1 after 15 days, and the kidney damage in the rats administered by AFB1 with time showed significantly cumulative effect.