OBJECTIVETo investigate the impact of prenatal exposure to diethylstilbestrol (DES) on the specific receptor LGR8 of insulin-like factor 3 (INSL3) in the mouse gubernaculum testis, and that of exoestrogens on descensus testis in mice.

METHODSA total of 120 pregnant KM mice aged 8 to 10 weeks were assigned to a normal, a blank control and 4 DES groups of equal number, the blank controls injected subcutaneously with dimethyl sulfoxide plus normal saline, and the DES groups with DES at 0.1, 1, 10 and 100 microg/kg body weight, respectively, from embryonic day 9 (ED9) through ED17. Immunohistochemistry and RT-PCR were used to detect the expressions of LGR8 protein and mRNA in the gubernaculum testis of the ED18 fetuses and PND20 (postnatal day 20) offspring of the mice.

RESULTSHistological analysis showed that the gubernaculum testis of the ED18 fetuses were well developed in both the normal and control groups, with an inner mesenchymal core and muscular outer layer. In contrast, the gubernaculum testis were poorly developed in the experimental groups, morphologically abnormal and without visible dividing line between the mesenchymal tissue and the muscular outer layer. No obvious differences were found in the gubernaculum testis development of the neonates between the normal and experimental groups. Positive immunostaining was seen in the mesenchymal core and muscular outer layer, but mainly in the latter. The expression of LGR8 was weaker in the experimental groups than in the normal group (P < 0.05), but that of LGR8 mRNA was increased in the high-dose (10 and 100 microg/kg) DES groups (P < 0.05). No obvious mutations were observed in the PCR products in any of the experimental groups.

CONCLUSIONPrenatal exposure to diethylstilbestrol affected the expression of LGR8 mRNA in the mouse gubernaculum testis, which suggests that diethylstilbestrol may induce cryptorchidism by interfering with the INSL3-LGR8 signaling system and consequently the development of the gubernaculum testis.