Influence of reproductive tract obstruction on expression of epididymal proteins and their restoration after patency

Abstract

Vasectomy is a simple and reliable method of male contraception. A growing number of men after vasectomy request vasectomy reversal due to various reasons. The pregnancy rate is lower than the patency rate after vasovasostomy and the pregnancy rate is time dependent. In this study, we evaluated the influence of reproductive tract obstruction on expression of epididymal proteins and their restoration after patency. Adult male Wistar rats were studied 30, 60 and 120 days after vasectomy, 30 days after vasovasostomy or after sham operations. Two-dimensional gel electrophoresis, mass-spectrometric technique, multidatabase search, Western blotting and real-time PCR were used to analyze the expression regulation of epididymal proteins. Total integrated intensity and total spot area of autoradiograms showed a consistent downward trend with time after obstruction, and this trend remained after patency. The intensity of the autoradiographic spots in three patency groups showed three trends: a downward trend, similar intensity and an upward trend compared with the correspondent obstruction group, respectively. Further verified experiments on human epididymis 2 (HE2), fertilization antigen-1 (FA-1), clusterin and PH20 demonstrated that compared with the correspondent obstruction group, the translation levels of HE2 and the mRNA transcription levels of HE2 showed an upward trend in patency groups, especially in the groups of obstruction for 60 days where the expression levels of HE2 were significantly upregulated after patency (P,0.05). Reproductive tract obstruction provokes a disregulation of gene expression in the epididymis and this disregulation remained after patency. Successful reversal may recover some proteins and the recovery is time dependent. Obstruction differentially alters mRNA transcription of different proteins and the content of proteins seemed to be easier to be influenced than the gene transcription. Vasovasostomy by modern microsurgical techniques remains the standard technique for vasectomy reversal with which all other methods of vasectomy reversal are compared. If success is defined that sperm can be detected in ejaculate following reversal, patency is over 80% in most microsurgical series, with patency approaching 100% in some reports. 1 However, pregnancies are obtained without assisted reproduction in 30%-75% of couples. 2 In other words, about 25% of couples are affected. Male factors account for about 50% of couples with infertility. 3 Approximately 10%-15% of infertile men suffer from azoospermia-complete absence of sperms in the ejaculate. Among these azoospermic patients, approximately 40% have complete obstruction in the ductal system and hence suffer from obstructive azoospermia. 4 Vasoepididymostomy is performed for congenital, infectious, postvasectomy or idiopathic epididymal obstruction. Following this type of microsurgery, 20%-40% of couples achieve pregnancy through intercourse without the assistance of reproductive techniques. 2 Similar to vasectomy reversal, the pregnancy rate is mu...