The structural morphology and epithelial association of spermatozoa at the uterotubal junction: a descriptive study of equine spermatozoa in situ using scanning electron microscopy.
Abstract: Uterotubal junction tissues (n=12) recovered from young nulliparous mares 4 h after insemination were examined for spermatozoa in situ using scanning electron microscopy. Mares were inseminated before ovulation with semen containing 66-85% morphologically abnormal spermatozoa and approximately 1 x 10(9) progressively motile spermatozoa. Spermatozoa were found in all the tissues and displayed a variety of relationships to the epithelium, depending on regional location, spatial constraints and epithelial surface characteristics. Spermatozoa were most abundant in the epithelial folds on the uterine side of the uterotubal junction papilla. More than 90% of the spermatozoa had normal morphology. These observations indicate that morphologically normal equine spermatozoa develop specific associations with the luminal epithelium of the reproductive tract during transport to the oviduct. Furthermore, the uterine papilla of the uterotubal junction may be a site of preovulatory sperm storage. The scarcity of morphologically abnormal spermatozoa, despite their abundance in the inseminate, indicates that most abnormal spermatozoa either do not reach the uterotubal junction or do not develop normal associations with the epithelium of the uterotubal junction. This observation provides evidence for a mechanism of sperm selection during transport. Hence, both normal morphology and progressive motility of spermatozoa should be considered in determining insemination doses, particularly for subfertile stallions.
Publication Date: 2000-01-01 PubMed ID: 20681154
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research study investigates the structural interactions between spermatozoa and the uterotubal junction in the reproductive tracts of mares, in situ using scanning electron microscopy. The findings suggest that normal equine spermatozoa associate with the epithelial lining of the reproductive tract, in their journey to the oviduct, whereas abnormal spermatozoa seem to be selected out in this process.
Methods and Samples
- The researchers obtained uterotubal junction tissues from 12 young mares that had not given birth before (nulliparous), four hours after insemination.
- Each mare was inseminated before ovulation with semen containing between 66-85% morphologically abnormal spermatozoa and about 1 billion progressively motile spermatozoa (sperm that move forward).
Observations and Findings
- Spermatozoa were detected in all the tissue samples and exhibited different relationships with the epithelium, which varied based on regional location, spatial confines, and the characteristics of the epithelial surface.
- The greatest concentration of spermatozoa was seen in the epithelial folds on the uterine side of the uterotubal junction papilla.
- Over 90% of the observed spermatozoa were morphologically normal, indicating that the majority of abnormal sperm cells either fail to reach the uterotubal junction or don’t establish normal associations with its epithelium.
- This research suggests the possibility of a sperm selection mechanism during transport within the reproductive tract.
- Overall, the observations imply that morphologically normal equine spermatozoa establish specific associations with the luminal epithelium (inner surface layer) of the reproductive tract on the route to the oviduct (the tube connecting the uterus and the ovaries).
Conclusion and Recommendations
- The findings of this study provide evidence that the uterotubal junction’s uterine papilla might be a preovulatory sperm storage site.
- It also recommends that both the normal morphology and the progressive motility of spermatozoa should be considered when determining insemination doses, especially for stallions with low fertility.
Cite This Article
APA
Scott MA, Liu IK, Overstreet JW, Enders AC.
(2000).
The structural morphology and epithelial association of spermatozoa at the uterotubal junction: a descriptive study of equine spermatozoa in situ using scanning electron microscopy.
J Reprod Fertil Suppl(56), 415-421.
Publication
Researcher Affiliations
- Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
MeSH Terms
- Animals
- Epithelium / physiology
- Epithelium / ultrastructure
- Female
- Horses / physiology
- Male
- Microscopy, Electron, Scanning
- Spermatozoa / cytology
- Spermatozoa / physiology
- Spermatozoa / ultrastructure
- Uterus / physiology
- Uterus / ultrastructure
Citations
This article has been cited 1 times.- Varner DD. Odyssey of the spermatozoon. Asian J Androl 2015 Jul-Aug;17(4):522-8.
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