出生前邻苯二甲酸二(2-乙基己基)酯暴露对成年后子代大鼠下丘脑昼夜节律相关基因表达的影响

Effects of prenatal exposure to di-(2-ethylhexyl) phthalate on expression of circadian rhythms-related genes in hypothalamus of adult offspring rats

目的探讨出生前邻苯二甲酸二(2-乙基己基)酯(di(2-ethylhexyl)phthalate,DEHP)暴露对成年后子代大鼠的昼夜节律相关基因表达的影响。方法将32只健康SD妊娠大鼠分为对照(玉米油)组和2、10、50 mg/kg DEHP染毒组,每组8只。在母鼠妊娠第14日至19日进行灌胃染毒,每日1次。子代大鼠于10周龄时,采用实时荧光定量PCR法检测下丘脑SCN核区Clock、Arntl、Dbp、Period1和Period2 5个昼夜节律相关基因的表达水平。结果与对照组相比,10、50 mg/kg DEHP染毒组成年雄性子代大鼠下丘脑SCN核团Dbp基因的表达水平下调,差异均有统计学意义(P<0.05);而各剂量组DEHP染毒组成年雄性大鼠下丘脑SCN核团的Clock、Arntl、Per1、Per2基因的表达水平均无明显改变。与对照组比较,50mg/kg DEHP染毒组成年雌性子代大鼠下丘脑SCN核团的Clock、Per1基因的表达水平均升高,差异有统计学意义(P<0.01);而各剂量DEHP染毒组成年雌性子代大鼠下丘脑SCN核团的Arntl、Dbp、Per2基因的表达水平均无明显改变。结论出生前DEHP暴露可能通过改变大鼠下丘脑SCN核区昼夜节律相关基因的表达影响成年后大鼠的昼夜节律调控功能,且这种影响具有性别差异。

Objective To investigate the effects of prenatal DEHP exposure on the expression of circadian rhythms-related genes of the adult offspring rats. Methods A total of 32 healthy pregnant SD rats were randomly divided into four groups,eight in each,including corn oil(vehicle control),2,10 and 50 mg/kg body weight DEHP treatment groups. From gestation days 14(GD14) to 19,the pregnant rats were treated with DEHP of different doses respectively through gavage once a day. At the age of10 weeks,the expression levels of five circadian-related genes in SCN of hypothalamus of the offspring rats was detected by real-time quantitative PCR. Results Compared with the control group,the expression level of Dbp gene in hypothalamic SCN nucleus of adult male offspring rats treated with 10 mg/kg and 50 mg/kg DEHP was down-regulated(P <0.05),and no significant change was seen in Arntl,Per1 and Per2 gene expression in the hypothalamus of adult male rats in each dose group(P >0.05). Compared with the control group,the expression levels of the Clock and Per1 gene in the hypothalamus of the hypothalamic SCN in female offspring treated with 50 mg/kg DEHP were up-regulated(P<0.01),and the expression levels of Arntl,DBP and Per2 gene in the hypothalamus in the female offspring of rats in each group did not present significantly change(P>0.05). Conclusion Prenatal DEHP exposure may affect the circadian rhythm regulation in adult offspring rats by changing the expression of circadian rhythm-related genes in the SCN nucleus of hypothalamus,which presents gender differences.