孕期五溴二苯醚暴露对母鼠甲状腺激素水平及仔鼠体格发育的影响

目的观察妊娠期五溴二苯醚(BDE-99)染毒对母鼠甲状腺激素水平及仔鼠体重和肛门-生殖器发育的影响。方法将24只SD孕鼠随机分为0.2、2和20 mg/kg BDE-99染毒组和溶剂对照组。妊娠期间,3个染毒组每天给予BDE-99灌胃,对照组孕鼠每天给予玉米油灌胃。在母鼠妊娠第11天和19天尾静脉采血,检测血清促甲状腺激素(TSH)、总甲状腺素(TT4)、游离甲状腺素(FT4)、三碘甲状腺原氨酸(TT3)和游离三碘甲状腺原氨酸(FT3)的水平,于仔鼠出生后第3、9、15、21和27天测定仔鼠体重,在仔鼠出生后第21天测定肛门-生殖器间距。结果妊娠第11天,2和20 mg/kg剂量组母鼠血清TT3和FT3水平均低于对照组(P<0.05)。妊娠第19天时,与对照组相比,各染毒组母鼠血清TT4水平均显著降低,其中20 mg/kg剂量组母鼠血清TSH水平低于对照组(P<0.05)。出生后第27天所有剂量染毒组雌性仔鼠的体重均低于对照组。20 mg/kg剂量组雄性仔鼠在出生后第21天的肛门-生殖器距离与对照组相比,有明显缩短(P<0.05)。结论孕期暴露于一定剂量水平的BDE-99可降低母鼠的甲状腺激素水平,并导致仔鼠出生后体重下降、肛门-生殖器间距缩短。

Effect of prenatal BDE-99 exposure on the maternal thyroid hormones levels and development of rat offspring

OBJECTIVE To investigate the effects of prenatal exposure to pentabromodiphenyl ether(BDE-99) on maternal serum thyroid hormone levels, as well as birth weight and anal-genital development in rat offspring. METHODS Pregnant SD rats were randomly treated with BDE-99(0.2, 2 and 20 mg/kg) or corn oil on gestational days 1-19. Maternal serum were collected from tail vein on the gestational day 11 and day 19, serum levels of TSH, TT4, FT4, TT3 and FT3 were measured. The weight of offspring was measured at postnatal day 3, 9, 15, 21 and 27, anorectal-genital spacing was measured at postnatal day 21. RESULTS The levels of TT3 and FT3 in maternal serum of 2 mg/kg and 20 mg/kg groups were lower than those of control group at gestational day 11. At gestational day 19, TT4 levels in maternal serum were significantly lower than those in control group, and TSH levels of 20 mg/kg group were lower than those in control group. The body weight of female offspring in all dose groups was lower than that of control group on the postnatal day 27, and the anal-genital distance of male offspring in the 20 mg/kg dose group was significantly lower than that of the control group on the postnatal day 21. CONCLUSION Prenatal exposure to BDE-99 may disrupt the maternal thyroid hormone levels, and cause the offspring’s weight loss and shortened anal-genital spacing.