邻苯二甲酸酯染毒哺乳期母鼠对雄性仔鼠睾丸Leydig细胞形态及功能的影响

The effects of DEHP on morphology and function of progenitor Leydig cell in rat

目的:观察邻苯二甲酸二乙基己基酯(DEHP)对哺乳期雄性仔鼠睾丸子Leydig细胞(PLC)形态和功能的影响及作用机制。方法:SD孕鼠20只,随机均分为4组(n=5):正常对照组,低剂量组,中剂量组,高剂量组。仔鼠出生第1天起分别以0、10、100、750 mg/(kg·d)DEHP灌胃染毒母鼠,直到仔鼠出生后21 d。用化学发光法检测雄性仔鼠血清睾酮(T)水平;测量体重、睾丸重量、肛生殖器距离(AGD);光镜及电镜下观察睾丸Leydig细胞形态结构;免疫组化方法检测睾丸类固醇激素合成急性调节蛋白(St AR)表达;Real-time PCR法检测睾丸胰岛素样生长因子Ⅰ(IGF-Ⅰ)mRNA的表达。结果:与正常组比较,低剂量组T无明显变化,中、高剂量组血清T水平明显降低(P<0.01)。低剂量组睾丸重量增加(P<0.05),高剂量组睾丸重量、仔鼠体重明显下降(P<0.01);中、高剂量组AGD明显缩短(P<0.01)。低剂量组睾丸Leydig细胞明显增生,呈簇状分布;中、高剂量组睾丸Leydig细胞灶区轻度增生,高剂量组部分生精小管生精细胞层次减少、生精细胞凋亡并脱落。电镜观察各给药组Leydig细胞胞浆脂质颗粒减少,线粒体、内质网减少。低剂量组IGF-ⅠmRNA表达增高(P<0.05);中、高剂量组睾丸St AR蛋白表达降低(P<0.05)。结论:哺乳期染毒DEHP可干扰仔鼠PLC的睾酮合成,St AR蛋白的降低和Leydig细胞的损伤可能是其机制。

Objective： To investigate the effects and mechanisms of diethylhexylphthalate（DEHP） on morphology and function of progeni- tor Leydig cells （PLC） in rats. Methods： Twenty pregnant SD rats were randomly divided into 4 groups （ n = 5）： normal control group, DEI-IP low dose group, middle dose group, and high dose group, which were treated from postnatal day （PND） 1 to PND 21 of the pubs with DEHP at the doses of 0, 10, 100, 750 rog/（kg·d） in0.5 ml of corn oil by gavage respectively. At the end of the treatment, the male pups were killed and blood samples were collected for determination of serum testosterone concentration by chemiluminescence method. The body weight, testis weight and anogenital distance （AGD） were measured. The morphology of PLC was observed by light and transmission electron microscopy. The protein expression of steroidogenic acute regulatory protein（StAR） in PLC was determined by immunohistochemistry. The mR- NA expression of insulin-like growth factor- I （ IGF- I- ）in the testis was assayed by real-time PCR. Results： Compared with normal control group, the serum testosterone and AGD of male pubs from the middle and high dose groups were declined significantly （ P 〈 0.01）, the testis weight and body weight from high dose group were decreased significantly （ P 〈 0.01）, while the testis weight increased in the low dose group （ P 〈 0.05）. Under light microscope, PLC showed hyperplasia and cluster aggregation in the low dose group and focal hyperplasia in the mid- dle and high dose group. The spermatogenic cells in seminiferous tubules showed decrease, apoptosis and unfix in the high dose group. Under transmission electron microscope, the PLC showed decreased lipid droplets, smooth endoplasmic reticulum and mitochondriae in the treated group. The mRNA expression of IGF- I- increased in the low dose group, and the protein expression of StAR decreased in the middle and high dose group. Conclusion： Lactating exposure to DEHP may interfere with the synthesis of testosterone of PLC in male pubs, the decrease of StAR and the damage of PLC may be involved in it.