Effect Of Exposure To Arsenic On Expressions Of Ddx3y In Sxr~b Region Of Y Chromosome In Male Mice

Background: Arsenic is characteristic of strong male reproductive toxicity,long-term exposure, which can affect sperm formation and development and damage reproductive function. However, the the mechanism of arsenic toxicity on male reproductive systemis is not very clear. Particularly, it has not been reported that the arsenic toxicity on sperm development may be induce by Y chromosome development-related genes.Objective: To investigate the testis and epididymis Y chromosome Ddx3y expression of mice through observing the sub-chronic arsenic exposure on spermatogenesis and development and explore the inherent relationship of arsenic to clarify the mechanism of male reproductive toxicity.Methods: Forty mice were divided into 4 groups of 12 each. Group 1 received drinking water alone (control). Group 2, 3 and 4 received 1 ,2 or 4 mg/kg arsenic trioxide respectively. Arsenic trioxide was given through drinking water. On the 60th day after As exposure, mice were decapitated and their testis and epididymis were removed. Expression of Ddx3y genes were examined in the testis and epididymis of mice exposed to As by Real-Time PCR. Western blotting and immunohistochemistry were used to detect Ddx3y protein expression and tissue distribution.Results: Compared with control group, the seminiferous epithelium section VII phase cells decreased at all levels, sperm motility was reduced, and malformation ratio increased. Quantitative PCR results showed that Ddx3y expression in mice testis, epididymis was significantly lower than the control group. Western blotting results showed that Ddx3y protein was significantly decreased by arsenic treated .Ddx3y protein in all stages of spermatogenic epithelium were distributed mainly in particular spermatogonia and primary spermatocytes and can be seen mainly in the basal cell cytoplasm in the epididymis.Conclusion: In the sub-chronic exposure circumstance, arsenic can affect sperm development and down-regulate the Y chromosome Ddx3y and protein expression in testis and epididymis. Ddx3y is likely to be the important target gene and closely relate to their mechanism of toxicity.