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Maturation of equine epididymal spermatozoa.
Abstract: Spermatozoa from four regions of the epididymis and from ejaculated semen were evaluated for their resistance to cold shock, progressive motility, and structural stability. Spermatozoa were incubated at 38 C and their percentage of eosinophilia was compared with that of spermatozoa cooled to 0 C in 2 minutes, 10 C in 12 minutes, or 4 C in 22 minutes. Spermatozoa motility was estimated visually under phase-contrast microscopy and was recorded by cinematography. Structural stability of spermatozoa incubated in 0.05 M sodium borate buffer, 0.035 M sodium dodecyl sulfate (SDS), 0.002 M dithiothreitol (DTT), or SDS+DDT was evaluated by phase-contrast and electron microscopy. The percentage of eosinophilic spermatozoa did not differ among regions of the epididymis and was not increased by cold shock. Cooling ejaculated spermatozoa to 0 C in 2 minutes increased (P < 0.01) the occurrence of eosinophilia (32% vs 73%). Spermatozoa released from the caput or proximal corpus epididymidis into 0.154 M NaCl were not progressively motile; only 4% of the spermatozoa from the distal corpus were motile Cauda epididymal and ejaculated spermatozoa exhibited similar motility (41% vs 47%). Stability of chromatin was greater in spermatozoa from the distal corpus than those from the caput epididymis. Chromatin of spermatozoa from the distal corpus was resistant to 7.5 minutes of SDS+DTT treatment, whereas virtually all spermatozoal nuclei from the caput were decondensed by SDS alone. Tail organelles of spermatozoa acquired stability between the proximal corpus and the cauda epididymidis. All tail organelles of spermatozoa from the proximal corpus were dissolved by 7.5 minutes of SDS treatment, whereas tail organelles of distal corpus epididymal spermatozoa had dissolved after 7.5 minutes of SDS+DTT treatment. Stability of tail organelles in cauda epididymal and ejaculated spermatozoa was similar. Seemingly, equine spermatozoa are infertile until they enter the cauda epididymidis.
Publication Date: 1980-08-01 PubMed ID: 7447113 The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
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This research investigates the maturation process of equine (horse) sperm cells, evaluating effects of temperature and chemical conditions on sperm cell stability and motility at various stages of maturation within different sections of the epididymis.
Investigation Methods
- The researchers collected sperm cells from four distinct regions of the horse’s epididymis and from ejaculated semen.
- The resistance of these sperm cells to sudden temperature changes (cold shocks), their progressive (forward) physical movement (motility), and the structural stability of the cells were assessed.
- To examine the effect of cold shock, the sperm cells were incubated at 38 C (body temperature), before being rapidly cooled to either 0 C, 10 C, or 4 C, then the percentage of eosinophilic (damaged) sperm cells was determined under these conditions.
- Sperm motility was observed visually under a microscope and recorded using cinematography.
- The structural stability of the sperm cells was assessed using various chemicals including a sodium borate buffer, sodium dodecyl sulfate (SDS), and dithiothreitol (DTT). The effect of these chemical treatments on the sperm was observed under microscopy.
Key Findings
- The research showed no difference in the percentage of damaged (eosinophilic) sperm cells among different regions of the epididymis and none was affected by cold shock.
- However, cooling ejaculated sperm cells from 38 C to 0 C in just 2 minutes significantly increased the occurrence of damage, as indicated by a higher percentage of eosinophilic sperm cells.
- Sperm cells from the head (caput) or the upper-middle part (proximal corpus) of the epididymis were not capable of progressive (forward) movement; only a small fraction of sperm cells (4%) from the lower-middle part (distal corpus) of the epididymis showed such motility. The sperm cells from the tail end (cauda) of the epididymis and those from ejaculated semen showed a similar and higher rate of motility.
- Sperm cells from the distal corpus of the epididymis showed greater chromatin (DNA-protein complex) stability, compared to those from the caput.
- The stability or resistance to decomposition of tail organelles in sperm cells increased between the proximal corpus and the cauda of the epididymis. After certain chemical treatments, all tail organelles in sperm cells from the proximal corpus dissolved, whereas the tails of the distal corpus epididymal sperm cells were only dissolved after a combined chemical treatment.
Conclusions
- The research concluded that equine sperm cells gain their motility and structural stability as they move from the head to the tail of the epididymis. This suggests that they remain infertile up to a certain stage in their movement along the epididymis, and only become fertile once they reach the tail (cauda) of the epididymis.
Cite This Article
APA
Johnson L, Amann RP, Pickett BW.
(1980).
Maturation of equine epididymal spermatozoa.
Am J Vet Res, 41(8), 1190-1196.
Publication
Researcher Affiliations
MeSH Terms
- Animals
- Cold Temperature
- Dithiothreitol / pharmacology
- Epididymis / anatomy & histology
- Horses / physiology
- Male
- Semen / cytology
- Sodium Dodecyl Sulfate / pharmacology
- Sperm Maturation
- Sperm Motility
- Spermatozoa / drug effects
- Spermatozoa / ultrastructure
Citations
This article has been cited 2 times.- Varner DD. Odyssey of the spermatozoon. Asian J Androl 2015 Jul-Aug;17(4):522-8.
- Cary JA, Madill S, Farnsworth K, Hayna JT, Duoos L, Fahning ML. A comparison of electroejaculation and epididymal sperm collection techniques in stallions. Can Vet J 2004 Jan;45(1):35-41.
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