苯甲酸雌二醇诱导小鼠尿道下裂动物模型的建立

目的:建立苯甲酸雌二醇诱导的小鼠尿道下裂模型,为研究雌激素致尿道下裂的分子作用机制提供进一步研究的基础。方法:100只ICR孕小鼠随机分成A、B、C、D、E 5组,每组20只,在孕12~16 d连续5 d各组每只皮下分别注射苯甲酸雌二醇0、0.2、1、5、25 mg.kg-1.d-1,出生时观察仔鼠死亡率。每组取2只母鼠所生的雄性仔鼠,解剖观察仔鼠睾丸位置、前列腺发育情况。出生后4周,观察有无尿道下裂和隐睾。结果:A、B、C、D、E各组仔鼠死亡率分别为21.6%、21.5%、41.4%、56.6%、75.0%。新生鼠解剖,各组均未发现前列腺,C、D、E组睾丸均在下极,A、B组睾丸均在膀胱两侧。仔鼠尿道下裂发生率分别为0、0、3.3%(2/60)、20.0%(8/40)、23.0%(6/26),尿道下裂发生率D、E组与A组间差异有显著性(P<0.05),而D、E组间差异无显著性(P>0.05);隐睾发生率分别为0、0、6.6%(4/60)、30.0%(18/60)、61.5%(16/26),隐睾发生率A、C组间差异无显著性(P>0.05),D、E组与A组间差异有显著性(P<0.05),而D、E组之间差异无显著性(P>0.05)。结论:孕鼠注射大剂量的雌激素可以诱导出仔鼠尿道下裂的模型,C组诱导率较低,D、E组诱导率接近,但是E组母鼠及其仔鼠死亡率均较高,因此5 mg.kg-1.d-1苯甲酸雌二醇用药量为小鼠尿道下裂造模的适宜剂量。

Establishment of a Mouse Model of Hypospadias Induced by Estradiol Benzoate

OBJECTIVE: To establish a mouse model of hypospadias induced by benzoate estradiol to further the studies on the molecular mechanisms of hypospadias. METHODS: A total of pregnant mice were randomly divided into 5 groups, Group A, B, C, D and E, and injected subcutaneously (sc) with estradiol benzoate at the dose of 0, 0.2, 1, 5 and 25 mg x kg(-1) d(-1) respectively from the 12th to the 16th gestational day. The mortality of the newborn mice was recorded and the male neonates of 2 pregnant mice from each group were anatomized to observe the testis position and prostate agenesis on the delivery day. Examinations were made for urethra and cryptorchidism on the 28th postnatal day. RESULTS: The death rates of the neonates in Group A, B, C, D and E were 21.6%, 21.5%, 41.4%, 56. 6% and 75.0%, respectively. Hypospadias was detected in Group C (3.3%, 1/30), D (20.0%, 4/20) and E (23.0%, 3/13), with significant difference between Group D and A (P < 0.05) and E and A (P < 0.05), but not between Group D and E (P > 0.05). Cryptorchidism was found in Group C (6.6%, 2/30) , D (30.0%, 6/20) and E (61.6%, 8/13), with significant difference between Group D and A (P < 0.05) and E and A (P < 0.05) , but not between Group D and E (P >0.05). CONCLUSION: Exposure of pregnant mice to large dose of estradiol benzoate can induce hypospadias and cryptorchidism in their neonates. And the right dose of estradiol benzoate for the establishment of the mouse model of hypospadias should be 5 mg x kg(-1) x d(-1).