Differential expression and localisation of heat shock protein 70 (HSP70) and glutathione peroxidase 5 (GPX5) in the testis and epididymis of Sonid Bactrian camels

Abstract

Context Heat shock protein 70 (HSP70) and glutathione peroxidase 5 (GPX5) are biomarkers of oxidative stress and stress in temperate, tropical environments, which are crucial for male reproduction. Their expression and distribution patterns in the testis and epididymis of Bactrian camels are still unknown. Aims This study aims to investigate the HSP70 and GPX5 expression and localisation in 3- and 6-year-old Bactrian camel testis and epididymis. Methods Reverse transcription quantitative polymerase chain reaction (qRT-PCR), Western blot and immunohistochemistry were used to detect HSP70 in the testis and epididymis (caput, corpus and cauda) and GPX5 in the epididymis at two developmental stages (3-year-old puberty group and 6-year-old adult group). Key results HSP70 was upregulated in the testis. Immunohistochemistry results indicated the HSP70 protein was mainly detected in spermatids and Leydig cells of testicular tissue. In the epididymis, HSP70 was located at the luminal spermatozoa, the epithelium lining the epididymal and the epididymal interstitium. GPX5 expression was significantly higher in the caput epididymis than in the corpus and cauda epididymis. GPX5 protein was observed in the epithelium lining the epididymal, interstitium and luminal spermatozoa in the epididymis by immunohistochemistry. Conclusions Bactrian camel HSP70 and GPX5 exhibited spatiotemporal expression specificity. Implications HSP70 and GPX5 may be essential for germ cell development and reproductive success after sexual maturation in Sonid Bactrian camels.