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Scrotal Heat Stress in Mice Affects Viability and DNA Integrity of Sperm, and Sex Ratio of the Offspring
Author(s) -
PérezCrespo M,
Pericuesta E,
Rey R,
GutiérrezAdán A
Publication year - 2006
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/j.1439-0531.2006.00774_1_6.x
Subject(s) - offspring , andrology , epididymis , sperm , biology , sex ratio , sperm motility , heat stress , semen , motility , zoology , genetics , pregnancy , medicine , population , environmental health
Heat stress causes infertility in farm animals and represents a major source of economic loss. The objective of this work was to examine the impact of scrotal heat stress (42°C for 30 min) on viability of spermatozoa, integrity of their DNA, and the in vivo reproductive performance of CD1 mice. These parameters were assessed in the spermatozoa recovered from epididymis at 0, 7, 14, 21 and 28 days after heat treatment. Heat stressed males were mated with CD1 females, and the number and the sex ratio of Day14 fetuses was analyzed by PCR. Heat stress increases the percentage of TUNEL positive sperm present in the epididymis at the time of heating (Day 0 and 7). Also the damage was significantly higher than the control at Day 14, 21 and 28 indicating that some germ cells, which were present within the testis at the time of heat stress, were not removed by apoptosis and completed their development producing sperm with damaged DNA. Heat stress also affects viability and motility at Day 14, 21 and 28. When the sex ratio of the offspring of the males mated the Day 0 or 7 after the heat stress was assessed, we observed that the percentage of males was significantly lower than expected (p < 0.05). No differences were observed in the sex ratio of the offspring of the other groups. In conclusion, these data demonstrate that the increase in epididymal temperature can compromise the DNA integrity of spermatozoa and the sex ratio of offspring generated with this sperm, and suggest that spermatocytes are most vulnerable than spermatids to DNA damage induced by heat stress.