邻苯二甲酸二丁酯致雄性仔鼠肛门直肠畸形与相关基因表达的研究

目的 邻苯二甲酸二丁酯(di-n-butyl phthalate,DBP)孕晚期染毒诱导子代雄性大鼠发生肛门直肠畸形(anorectal malformations,ARMs),探讨形态学变化及相关基因的表达.方法 孕鼠20只,随机分为两组,在怀孕天数第12～18天,每日分别给予DBP及大豆油850mg/kg灌胃.出生后(PND)1d统计雄性仔鼠肛门闭锁发生率,测量雄性仔鼠体重和肛门生殖器距离(AGD),观察肛门闭锁雄性仔鼠末端直肠及肛周病理学改变.Real-time PCR法检测雄性仔鼠末端直肠组织中Shh、Gli2、Gli3、Bmp4、Wnt5a、Hoxa13、Hoxd13、Fgf10、Fgfr2基因mRNA的表达水平.结果 与对照组相比,DBP染毒组母鼠孕期体重增量减少,孕期延长,仔鼠产量降低(P＜0.05),PND 1d肛门闭锁雄性仔鼠体重及AGD较对照组明显降低(P＜0.05).染毒组雄性仔鼠肛门闭锁发生率大约为39.5％.肛门闭锁雄性仔鼠PND1末端直肠及肛周组织病理显示典型的ARMs.与对照组相比,肛门闭锁雄性仔鼠PND1末端直肠中Shh、Gli2、Gli3、Bmp4、Wnt5a、Hoxa13、Hoxd13、Fgf10、Fgfr2的mRNA表达水平较对照组也明显降低(P＜0.05).结论 DBP孕晚期染毒能明显诱导雄性仔鼠ARMs发生,并对其生长发育具有不良影响,其末端直肠组织中与肛门直肠分化发育相关的基因Shh、Gli2、Gli3、Bmp4、Wnt5a、Hoxa13、Hoxd13、Fgf10、Fgfr2的mRNA的表达水平降低可能促进ARMs的发生.

Genetic characterization and morphological assessment of anorectal malformations in male rat offspring induced by di-n-butyl phthalate

Objective To induce anorectal malformations (ARMs) in male rats by maternal exposure to di-n-butyl phthalate (DBP) during late pregnancy and examine the genetic characterization and morphological abnormalities in male offspring.Methods Twenty timed pregnant rats were randomly divided into two groups.DBP was administered by gastric intubation at a dose of 0,850 mg/kg/d from gestation day (GD) 12 to 18.On postnatal day (PND) 1,the incidence of ARMs was evaluated and body weight and anogenital distance (AGD) were measured.Themorphological abnormalities of ARMs were observed by histology.The mRNA expressions of such genes as Shh,Gli2,Gli3,Bmp4,Wnt5a,Hoxa13,Hoxd13,Fgf10 and Fgfr2 associated with anorectal development were examined by real-time polymerase chain reaction (PCR) in terminal rectum of ARM male offspring.Results The incidence of ARMs was 39.5％.Body weight and AGD of ARM male rats on PND1 were signi cantly lower than those of control (P＜0.05).The presence of ARMs was confirmed histologically.Remarkably decreased mRNA expressions of the above genes were observed in terminal rectum of ARM male offspring (P＜0.05).Conclusions During late pregnancy,an exposure to DBP at a dose of 850 mg/kg/d may lead to a high incidence of ARMs and developmental damage in male rats.And the down-regulations of the relevant genes may disturb the signaling networks in terminal rectum of ARMs.