Effects of an anti-gonadoliberin releasing hormone vaccine on testicular, epididymal and spermatogenic development in the horse.
Abstract: The effects of the GnRH vaccine Improvac on testicular and epididymal morphometrics, histology and spermatogenesis were measured in 19 young (15-20 months) colts randomly assigned to one control (saline, castration at 57 days, n = 6) or either of two GnRH vaccine-treatment groups, T-57 (castration at 57 days, n = 7) or T-100 (castration at 100 days, n = 6), respectively. All were immunized on Day 0 with a single booster on Day 28. Excised testes and epididymides were weighed and processed for histology to measure tubule, epithelial and muscle dimensions, the ratio of interstitial tissue to seminiferous tubules and determine the stage of spermatogenesis. Testis volume, unchanged within controls, decreased in T-57 and T-100 groups by 50% and 70%, respectively. Treated colts' testes were significantly lighter than controls (64% relative difference); however, epididymal mass showed no significant differences between groups. Proportionally less seminiferous tubule relative to interstitial tissue was observed in both treatment groups (5%) versus controls (22%) with a mean tubule size 28% smaller than controls. Controls exhibited a high proportion of seminiferous tubules with advanced stages of spermatogenesis, whereas treated colts showed a high proportion of tubules in the early stages of spermatogenesis. In conclusion, immunization against GnRH in prepubertal colts was effective at reducing the development of their intra-scrotal reproductive organs and preventing normal spermatogenesis. GnRH vaccination of young colts effectively and consistently reduced testis mass, tubule size and relative proportion of seminiferous tubule tissue while retarding spermatogenesis. The epididymis showed changes with a smaller tubule diameter, lower epithelial height and thicker muscle layer recorded in treated compared to control colts.
© 2022 The Authors. Reproduction in Domestic Animals published by Wiley-VCH GmbH.
Publication Date: 2022-05-12 PubMed ID: 35500167PubMed Central: PMC9543562DOI: 10.1111/rda.14141Google Scholar: Lookup
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- Journal Article
- Randomized Controlled Trial
- Veterinary
Summary
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The study is about understanding the impact of a specific GnRH vaccine, named Improvac, on the development of testicles, epididymis, and sperm production in young horses.
Research Methods
- Nineteen young colts aged between 15 to 20 months were selected for this study.
- These colts were randomly allocated into one control group (given saline and castrated on day 57, n = 6) and two treatment groups; T-57 (castrated on day 57, n = 7) and T-100 (castrated on day 100, n = 6).
- All colts were immunized on the first day and given a booster on the 28th day.
- Post removal, the weight of testes and the epididymis was recorded.
- They were then processed for histology to measure the size of the tubule, epithelial and muscle dimensions, the proportion of interstitial tissue to seminiferous tubules, and to determine the stage of sperm production.
Findings
- The volume of the testes, unchanged within controls, decreased in T-57 and T-100 groups by 50% and 70% respectively.
- Testes of treated colts were significantly lighter than controls (64% relative difference).
- However, no significant differences were observed in the mass of the epididymis across the groups.
- The proportion of seminiferous tubule relative to interstitial tissue was lower in treatment groups (5%) compared to controls (22%); tubule size was 28% smaller than controls.
- Advanced stages of sperm production were observed in the seminiferous tubules of the control group, while early stages of sperm production were seen in the treatment groups.
Conclusion
- Immunization against GnRH in prepubertal colts was found to be effective in reducing the development of their intra-scrotal reproductive organs and obstructing normal sperm production.
- Vaccinating young colts with GnRH consistently resulted in a decrease in the mass of testis, size and relative proportion of seminiferous tubule tissue, and slowing down the process of sperm production.
- The epididymis showed changes with a smaller tubule diameter, lower epithelial height and thicker muscle layer noted in the treated group when compared to the control group.
Cite This Article
APA
Botha AE, Schulman ML, Birrell J, du Plessis L, Laver PN, Soley J, Colenbrander B, Bertschinger HJ.
(2022).
Effects of an anti-gonadoliberin releasing hormone vaccine on testicular, epididymal and spermatogenic development in the horse.
Reprod Domest Anim, 57(8), 919-927.
https://doi.org/10.1111/rda.14141 Publication
Researcher Affiliations
- Section of Reproduction, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
- Section of Reproduction, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
- Veterinary Population Management Laboratory, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
- Veterinary Division, South African Police Services, Pretoria, South Africa.
- Electron Microscope Unit, Department of Anatomy and Physiology, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
- Electron Microscope Unit, Department of Anatomy and Physiology, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
- Electron Microscope Unit, Department of Anatomy and Physiology, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
- Equine Sciences Department, Faculty of Veterinary Medicine, University of Utrecht, Utrecht, The Netherlands.
- Section of Reproduction, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
- Veterinary Population Management Laboratory, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
MeSH Terms
- Animals
- Epididymis
- Gonadotropin-Releasing Hormone / pharmacology
- Horses
- Male
- Seminiferous Tubules
- Spermatogenesis / physiology
- Testis / physiology
- Vaccines
Conflict of Interest Statement
All authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.
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