[Effects of Di (2-ethylhexyl) phthalate on the testis and testicular gubernaculum of fetal KM mice].

OBJECTIVE: To explore the effects of Di (2-ethylhexyl) phthalate (DEHP) on the testis and testicular gubernaculum of fetal KM mice in vivo and to investigate the mechanism of DEHP-induced cryptorchidism.

METHODS: Thirty healthy pregnant KM mice were randomly and equally divided into a blank control group, a corn oil control group and a DEHP group. The pregnant mice in the latter group were exposed to DEHP by gavage at the dose of 500 mg/kg body weight per day from gestation day 12 (GD12) through gestation day 19 (GD19). The effects of DEHP were observed on the number of fetuses per pregnancy, the ratio of male to female pups, the weight of the testis, the morphology and location of the testis and gubernaculum, the relative testis-bladder neck distance (TBD) and cranial suspensory ligament (CSL) residual. The expressions of the androgen receptor (AR), estrogen receptor (ER) and actin and proliferating cell nuclear antigen (PCNA) in the gubernaculum were detected by immunohistochemistry.

RESULTS: DEHP reduced the testis weight and TBD, induced different degrees of testis maldescent, but produced no obvious effect on the body weight, the number of fetuses per pregnancy, the sex ratio and the testis gubernacular morphology. Under the light microscope, hypotrophy was seen in all the testis seminiferous tubules, spermatogenic cells and Sertoli cells, marked Leydig cell hyperplasia was noted, and the positive expression of AR in the gubernaculum was decreased in the DEHP group (P < 0.01).

CONCLUSION: DEHP could cause dysfunction of the testis gubernaculum via its anti-androgen effect, induce cryptorchidism, and cause dysplasia and dysfunction of Sertoli cells, Leydig cells and spermatogenic cells in fetal mice.