[The effects of di-(2-ethylhexyl) phthalate (DEHP) in testosterone synthesis and its molecular mechanisms in the fetal testis of male mouse by organ culture in vitro].

Objective: To investigate the effects of DEHP in testosterone synthesis and the related genes expression in the fetal testis of male mouse by organ culture in vitro.

Methods: The testis tissues were cultured in infiltrating type rotating device for 72 hours. The culture and gas were changed every 24 hours. The testis tissues were divided into the DMSO control group and four DEHP groups (the terminal concentration were 0.1, 1.0, 10.0, 100.0 micromol/L). The testosterone levels in the cultured medium were measured by radioimmunoassay, the INHBbeta levels were measured by Elisa, the gene expressions related with testosterone synthesis were detected by real-time PCR, the morphological changes of cultured testis were observed by HE staining under optical microscope, the expressions of related proteins were measured by immunohistochemistry.

Results: Compared to the control group, the levels of testosterone synthesis in 0.1, 1.0, 10.0 micromol/L groups were increased, but decreased in 100.0 micromol/ L group which were exposed in DEHP for 48 hours and 72 hours. There was an increase of INHBbeta synthesis in 0.1 and 1.0 micromol/L groups, but a decrease in 10.0 and 100.0 micromol/L groups. The gene expressions of 3beta-HSD, P450c17, P450Scc, vimentin were significantly decreased compared to that of control group especially in 1.0 and 10.0 micromol/L groups (P < 0.05), but the expressions of INHBbeta had no significant changes. There were no apparent morphological changes in testis tissue by HE staining. A significant increase of the three proteins (3beta-HSD, P450c17, P450Scc) and a significant decrease of vimentin were observed in 10.0 and 100.0 micromol/L groups (P < 0.05).

Conclusion: DEHP exposure can affect the testosterone synthesis in the fetal testis of male mouse. The regulation of gene expression involving in testosterone synthesis might be the mechanism.