Whole-body heat exposure induces membrane changes in spermatozoa from the cauda epididymidis of laboratory mice.
This study was carried out to determine if exposure to hot environmental temperatures had a direct, detrimental effect on sperm quality. For this the effect of whole-body heat exposure on epididymal spermatozoa of laboratory mice was investigated. C57BL/6 mice (n = 7) were housed in a microclimate chamber at 37 degrees C-38 degrees C for 8 h per day for three consecutive days, while control mice (n = 7) were kept at 23 degrees C-24 degrees C. Cauda epididymal spermatozoa were obtained 16 h after the last heat treatment. The results showed that sperm numbers were similar in the two groups (P = 0.23), but after heat treatment, a significant reduction in the percentage of motile sperm was present (P < 0.0001). Membrane changes of the spermatozoa were investigated by staining with phycoerythrin (PE)-conjugated Annexin V, which detects exteriorization of phosphotidylserine from the inner to the outer leaflet of the sperm plasma membrane, and 7-aminoactinomycin D (7-AAD), which binds to the sperm nucleus when the plasma membrane is damaged. The percentage of spermatozoa showing positive staining with Annexin V-PE or 7-AAD or both, was significantly higher (P < 0.05) in heat-exposed mice compared with controls. These results show that whole-body heat exposure to 37 degrees C-38 degrees C induces membrane changes in the epididymal spermatozoa of mice, which may lead to apoptosis.
Wechalekar
Harsha
H
Discipline of Anatomy and Pathology, School of Medical Sciences, Faculty of Health Sciences, University of Adelaide, Adelaide, South Australia, Australia.
Setchell
Brian P
BP
Peirce
Eleanor J
EJ
Ricci
Mario
M
Leigh
Chris
C
Breed
William G
WG
D000818:Animals; D017304:Annexin A5; D002462:Cell Membrane / Q000378:metabolism*; D003609:Dactinomycin / Q000031:analogs & derivatives; D004822:Epididymis / Q000166:cytology; D006358:Hot Temperature / Q000009:adverse effects*; D008297:Male; D051379:Mice; D013076:Sperm Count; D013081:Sperm Motility; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism*; D013194:Staining and Labeling
D017304:Annexin A5; D003609:Dactinomycin; C025942:7-aminoactinomycin D