Isobaric tags for relative and absolute quantification-based proteomic analysis of testis biopsies in rhesus monkeys treated with transient scrotal hyperthermia.

Meng Rao,Shifu Hu,Changhong Zhu,Hui Lei,Wei Xia,Yanqing Wu,Sha Ma,Yanfei Zhou

doi:10.18632/oncotarget.20719

Abstract

This study aimed to examine the cellular and molecular events that occur in rhesus monkey testes after scrotal hyperthermia. Eight male adult rhesus monkeys were subjected to scrotal hyperthermia at 43°C for 30 min daily for 6 consecutive days. Sperm concentration, reproductive hormones, and testis histology were examined before hyperthermia (day 0), and at 8, 15, 30, 45, 60, 75, and 90 days after the initiation of hyperthermia. iTRAQ-based proteomic analysis was conducted on testicular tissues collected on days 0, 8, and 60 to identify differentially expressed proteins at the early and recovery stages of testicular damage. The sperm concentration was significantly decreased at days 30 and 45 after treatment (p < 0.01) and recovered to baseline at day 60. When compared with day 0, 101 and 24 differentially expressed proteins were identified at days 8 and 60 after heat treatment, respectively. The molecular functions of the differentially expressed proteins at day 8 were mainly nucleic acid binding, unfolded protein binding, nucleotide binding, and nucleoside phosphate binding. Spliceosome was enriched as the most significant pathway at day 8. CIRBP, PSIP1, Sam68, and Decorin were validated and found to be consistent with the proteomic data, indicating the reliability of the proteomic profiles identified in this study. In summary, we suggest that the proteins identified in this study may play important roles in heat-induced spermatogenic impairment. Some of these proteins, such as CIRBP, PSIP1, Sam68, and Decorin, may be early molecular targets responsible for spermatogenesis suppression induced by heat treatment.

Highlights

In most mammals, including humans, the testes are located in the scrotum outside the main body cavity to maintain a lower-temperature environment for normal spermatogenesis [1]
Reproductive hormones, and testis histology were examined before hyperthermia, and at 8, 15, 30, 45, 60, 75, and 90 days after the initiation of hyperthermia. isobaric tags for relative and absolute quantification (iTRAQ)-based proteomic analysis was conducted on testicular tissues collected on days 0, 8, and 60 to identify differentially expressed proteins at the early and recovery stages of testicular damage
We attempted to delineate the early testicular cell response to heat treatment and to elucidate the underlying molecular mechanism involved in heat-induced suppression of spermatogenesis

Summary

Introduction

In most mammals, including humans, the testes are located in the scrotum outside the main body cavity to maintain a lower-temperature environment for normal spermatogenesis [1]. Cryptorchidism and varicocele are the main endogenous factors that lead to testicular hyperthermia and affect normal spermatogenesis [2, 3]. Scrotal heat stress from occupational exposure to high environmental temperatures, such as that experienced www.impactjournals.com/oncotarget by welders and drivers, can have a deleterious effect on spermatogenesis [4, 5]. In our previous clinical study, we simulated a hot tub environment and exposed healthy adult volunteers to scrotal hyperthermia at 43°C ten times for 30 min each, once daily or once every 3 days [6, 7]. The complicated process of apoptosis is regulated by many factors, and the molecular mechanisms that underlie this process are still largely unknown

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