孕期接触四氯联苯对大鼠母性行为的影响

为评价多氯联苯对人体发育的影响，本研究以大鼠为模型，研究多氯联苯（PCB）对母性行为的影响。将50只同期怀孕的Long-Evans大鼠随机分为5组，在怀孕第7－18天，每天给大鼠肌注四氯联苯或芝麻油。1组、2组，按每kg体重分别注射1mg、20mg2，2′，4，4′－四氯联苯（PCB47）；3组、4组，按每kg体重分别注射0.25mg、1mg3，3′，4，4′－四氯联苯（PCB77）；5组（对照组）注射芝麻油。产仔后的第0、3、6、12、15天分别观察母鼠的筑窝、舔仔、自发叼仔和诱发叼仔、蹲伏和在窝内的时间。结果表明：对照组母鼠在30min的观察中，其窝内时间与幼仔出生后天娄和负相关，而接触PCB的母鼠的窝内时间与幼仔出生天数无相关关系。接触PCB47的母鼠的筑巢、蹲伏、舔仔、自发叼仔行为在幼仔出生后的第0天和6天与对照组有显著差异，而接触PCB77的母鼠仅在第15天与对照组大鼠有区别。在诱导叼仔的实验中，接触PCB77的母鼠的叼仔时间在幼仔出生后的第12天增加。

EFFECTS OF TETRACHLOROBIPENYLS ON MATERNAL BEHAVIOR IN LABORATORY RATS

Polychlorinated biphenyls (PCB′s) are widespread environmental contaminants that are possible health hazards for humans. To evaluate the developmental effects of PCBs on human beings, rats were used as a model to study the effects of PCBs on maternal behavior. Five groups of time-mated Long-Evans rats (Rattus norvegicus) were injected daily with either non-coplanar 2,2′,4,4′-tetrachlorobiphenyl (PCB 47) at the dosage of 1 or 20 mg/kg body weight, or with coplanar 3,3′,4,4′- tetrachlorobiphenyl (PCB 77) at the dosage of 0.25 or 1 mg/kg body weight or sesame oil (control group). Treatment extended from gestational day 7 to 18. All the behavioral tests were done between 09:00 to 14:00 h under red illumination. A thirty-minute maternal behavior test and an induced retrieving test were performed once every three days with the former from postnatal day (PND) 0 to 15 and the latter from PND 0 to 12.If the tests were given on the same day the maternal behavior test was done first. Results show that control mothers spent less time with pups in the nest as they got older. However, PCB-treated females did not respond in this way. PCB 47-treated mothers showed significant differences in the duration of crouching, licking, spontaneous retrieving and nest building on PND 0 and 6, whereas PCB 77-treated mothers showed significant differences in the duration of crouching and time in the nest only on PND 15.During tests for induced retrieving of pups, PCB 77-treated mothers showed an increase in the duration of retrieving on PND 12.The results of this study suggest that PCBs disturb the maternal behavior of rats and could have potentially negative effects on humans.