115. WHOLE BODY HEAT EXPOSURE INDUCES APOPTOSIS IN MOUSE CAUDAL EPIDIDYMAL SPERMATOZOA
H. Wechalekar A , B. P. Setchell A , W. G. Breed A , M. Ricci A , C. Leigh A and E. Peirce ADiscipline of Anatomical Sciences, University of Adelaide, Adelaide, SA, Australia
Reproduction, Fertility and Development 21(9) 34-34 https://doi.org/10.1071/SRB09Abs115
Published: 26 August 2009
Abstract
Introduction: The aim of the present study was to determine the immediate effects of whole body heating on sperm numbers, motility and apoptosis. Material and Methods: C57BL/6 mice (n=7) were exposed to 37-38oC (8 hours/day), for three consecutive days while control mice (n=7) were kept at 23-24oC. Caudal epididymal spermatozoa were collected from control and heat treated mice 16 hours after the last heat treatment to determine the sperm number and motility using a Neubauer haemocytometer and sperm apoptotic changes by dual color flow cytometry using Annexin V/PE (Annexin V conjugated with phycoerythrin) and 7AAD (7-amino-actinomycin D) stains. Results: There were no significant differences (p>0.05) in sperm numbers between heat treated and control mice, however heating did result in a significant reduction in sperm motility (p<0.05). Apoptosis staining identified four different subpopulations of spermatozoa: (a) live spermatozoa (Annexin V-/7AAD-), (b) early apoptotic spermatozoa with exteriorized phosphotidylserine (PS) receptor and intact plasmalemma (Annexin V+/7AAD-), (c) late apoptotic spermatozoa with PS receptor translocation and leaky plasmalemma (Annexin V+/7AAD+) and (d) dead spermatozoa with damaged plasmalemma with no detectable PS receptor (Annexin V-/7AAD+). Heating resulted in significant reduction in the percentage of live spermatozoa (p<0.05), an increase in early apoptotic (p<0.05), late apoptotic (p<0.05), and dead spermatozoa (p<0.05). Conclusion: This study shows that mice exposed to whole body heat exposure of 37-38oC for 8 hours per day for three consecutive days exhibited early and late apoptotic changes to epididymal spermatozoa. These findings suggest possible adverse effects of exposure to high temperature on the viability of human spermatozoa in the epididymides. In addition, these findings reinforce the importance of temperature during sperm preparation procedures in infertility clinics, and research laboratories.
