Scrotal heat stress induces altered sperm chromatin structure associated with a decrease in protamine disulfide bonding in the stallion.
Abstract: A variety of testicular insults can induce changes in the structure of spermatozoal chromatin, resulting in spermatozoal DNA that is more susceptible to acid-induced denaturation. The degree of change in the DNA can be measured using the sperm chromatin structure assay (SCSA). The SCSA measures the relative amounts of single- and double-stranded DNA after staining with the metachromatic dye, acridine orange. Here we used a stallion model (n = 4) to study the effects of scrotal heat stress on spermatozoal DNA. This model was created by insulating stallion testes for 48 h and collecting sperm daily thereafter for 60 days. Changes in the SCSA were then correlated with protamine disulfide content and protamine types and levels. Results of the SCSA indicated that the susceptibility of spermatozoal DNA to denaturation was dependent on the spermatogenic cell stage that the ejaculated sperm was in at the time of the heat stress. Spermatozoa with altered DNA had a decrease in the extent of disulfide bonding that was associated with an increase in the susceptibility of DNA to denaturation. However, there were no detectable changes in either the protamine type or level. Thus, in this model, decreased disulfide bonding is associated with an increased susceptibility of spermatozoal DNA to denaturation in the absence of protamine changes.
Publication Date: 1999-02-20 PubMed ID: 10026107DOI: 10.1095/biolreprod60.3.615Google Scholar: Lookup
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- Journal Article
Summary
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The research demonstrates that exposure to scrotal heat stress in stallions can cause changes in the structure of sperm chromatin and result in more vulnerable spermatozoal DNA. The susceptibility of this DNA to breakdown was found to be linked to the stage of sperm cell development at the time of the heat exposure.
Objective of the Research
- This research aims to study the effects of scrotal heat stress on the spermatozoal DNA in stallions. The researchers used a sperm chromatin structure assay (SCSA) to measure the changes in DNA structure after exposure to heat stress.
Method of the Study
- A stallion model was used in the study, with four stallions participating.
- The testicles of the stallions were insulated for 48 hours to create a condition of scrotal heat stress.
- Sperm were collected daily for 60 days after the insulation period and the SCSA used for assessment.
Key Findings
- Changes in the sperm chromatin structure, measured by the SCSA, were found to correlate with changes in protamine disulfide content and types and levels of protamine.
- The susceptibility of spermatozoal DNA to break down was shown to depend on the development stage of the sperm cell when exposed to heat stress.
- Spermatozoa with altered DNA exhibited a decrease in the amount of disulfide bonding, thereby increasing the vulnerability of the DNA to breakdown.
- Interestingly, despite these changes, no detectable changes were found in the type or level of protamine in the sperm cells.
Conclusion of the Research
- The research concluded that scrotal heat stress results in alterations in the sperm chromatin structure, which increases the susceptibility of spermatozoal DNA to breakdown.
- This increased vulnerability is linked with decreased disulfide bonding but is not associated with any detectable changes in protamine levels or types.
Cite This Article
APA
Love CC, Kenney RM.
(1999).
Scrotal heat stress induces altered sperm chromatin structure associated with a decrease in protamine disulfide bonding in the stallion.
Biol Reprod, 60(3), 615-620.
https://doi.org/10.1095/biolreprod60.3.615 Publication
Researcher Affiliations
- Hofmann Center for Reproductive Studies, University of Pennsylvania School of Veterinary Medicine, Kennett Square, Pennsylvania 19348, USA. charleslov@aol.com
MeSH Terms
- Animals
- Chromatin / chemistry
- Chromatin / ultrastructure
- DNA / analysis
- DNA / chemistry
- Disulfides / metabolism
- Female
- Horses
- Hot Temperature
- Male
- Nucleic Acid Denaturation
- Protamines / metabolism
- Scrotum / cytology
- Spermatozoa / ultrastructure
Citations
This article has been cited 6 times.- Kang H, Zsoldos RR, Sole-Guitart A, Narayan E, Cawdell-Smith AJ, Gaughan JB. Heat stress in horses: a literature review.. Int J Biometeorol 2023 Jun;67(6):957-973.
- Ribas-Maynou J, Benet J. Single and Double Strand Sperm DNA Damage: Different Reproductive Effects on Male Fertility.. Genes (Basel) 2019 Jan 31;10(2).
- Takahashi M. Heat stress on reproductive function and fertility in mammals.. Reprod Med Biol 2012 Jan;11(1):37-47.
- Raad G, Hazzouri M, Bottini S, Trabucchi M, Azoury J, Grandjean V. Paternal obesity: how bad is it for sperm quality and progeny health?. Basic Clin Androl 2017;27:20.
- Zhang MH, Shi ZD, Yu JC, Zhang YP, Wang LG, Qiu Y. Scrotal heat stress causes sperm chromatin damage and cysteinyl aspartate-spicific proteinases 3 changes in fertile men.. J Assist Reprod Genet 2015 May;32(5):747-55.
- Hekmatdoost A, Lakpour N, Sadeghi MR. Sperm chromatin integrity: etiologies and mechanisms of abnormality, assays, clinical importance, preventing and repairing damage.. Avicenna J Med Biotechnol 2009 Oct;1(3):147-60.
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