Identification of New Epididymal Luminal Fluid Proteins Involved in Sperm Maturation in Infertile Rats Treated by Dutasteride Using iTRAQ.

Rui-Hua Zhong,Shu-Wu Xie,Jie-Yun Zhou,Li-Juan Qu,Qian Wang,Yan Zhu,Yang Cao,Xiang-Jie Guo,Guo-Ting Li

doi:10.3390/molecules21050602

Abstract

Background: Spermatozoa become mature and acquire fertilizing capacity during their passage through the epididymal lumen. In this study, we identified new epididymal luminal fluid proteins involved in sperm maturation in infertile rats by dutasteride, a dual 5α-reductase inhibitor, in order to provide potential epididymal targets for new contraceptives and infertility treatment. Methods: Male rats were treated with dutasteride for 28 consecutive days. We observed the protein expression profiles in the epididymal luminal fluids in infertile and normal rats using isobaric tags for relative and absolute quantitation (iTRAQ) technique. The confidence of proteome data was validated by enzyme-linked immunosorbent assays. Results: 1045 proteins were tested, and 23 of them presented different expression profiling in the infertile and normal rats. The seven proteins were down-regulated, and 16 proteins were up-regulated. Among the seven proteins which were significantly down-regulated by dutasteride in the epididymal luminal fluids, there were three β-defensins (Defb2, Defb18 and Defb39), which maybe the key proteins involved in epididymal sperm maturation and male fertility. Conclusions: We report for the first time that dutasteride influences the protein expression profiling in the epididymal luminal fluids of rats, and this result provides some new epididymal targets for male contraception and infertility therapy.

Highlights

Testicular spermatozoa released into the seminiferous tubule are not yet mature or fertile.They become mature and acquire fertilizing capacity during the passage through the epididymal lumen [1,2]
There was a significant decrease in the percentage of motile and progressively motile sperm (39% and 45%, respectively) from the cauda epididymis of treated male rats compared with untreated animals (Figure 1)
We discovered that the down-regulated epididymal luminal fluid proteins were three β-defensins, which were deemed to be related to epididymal sperm maturation/fertilization and were presumed to be the potential targets for new contraceptives

Summary

Introduction

Testicular spermatozoa released into the seminiferous tubule are not yet mature or fertile They become mature and acquire fertilizing capacity during the passage through the epididymal lumen [1,2]. Molecules 2016, 21, 602 barrier formed by tight junctions from the epithelial cells in the epididymis [6] This barrier isolates the spermatozoa from the body fluids, from their formation to their maturation [7]. This physical separation by the blood barrier plays a vital role in protecting spermatozoa from autoimmune reactions that could occur due to specific epididymal protein secretions associated with the terminal cellular differentiation of the gametes [8,9]. We identified new epididymal luminal fluid proteins involved in sperm maturation in infertile rats by dutasteride, a dual 5α-reductase inhibitor, in order to provide potential epididymal targets for new contraceptives and infertility treatment

Methods

Results

Conclusion