Abstract:
Most of the scientific researches, regarding the epididymal functions of epididymis deal with
epididymal sperm maturation but not sperm storage. Therefore, the present experiments were
carried out to determine sperm transfer time and sperm retention times of different regions of
hamster epididymis, sperm storage time in the cauda epididymis and functional ability of
cauda sperm after placing ligations. To study the sperm transfer times and retention times in
different regions of the hamster epididymis, the initial segment was blocked by placing a
ligation at the junction between the initial segment and the caput region. The study was
focused on sperm motility, total sperm count, sperm morphology and sperm emptying times
and sperm transfer times in different regions in different post ligation days up to 78 days.
Sperm emptying time was approximately 18 days in the caput alone, 14 days in the corpus
region and 46 days in the cauda. By 15 days, sperm motility was decreased rapidly in all
regions of the epididymis and the majority of sperms were immotile by the 24th day of post
ligation. Higher numbers of abnormal sperm were seen from day 36 to day 78 post ligation.
According to histological studies, epididymal epithelial structure showed marked alterations
compared to the control. Epithelium of the epididymis became stratified and made clusters after
12 days of post ligation in proximal regions of the epididymis and the cauda epithelium became
more flattened.
Ligation of epididymal tubule at the junction between the distal corpus and the proximal cauda
was carried out to determine the storage time; the hamster sperms are able to stay viable in cauda
epididymis. Motility, viability and morphology of cauda sperm were also studied during the
storage time. On day 40, the total number of cauda sperms was reduced remarkably (5 x 106±
2227/ml). That amount is more than fifty times reduction when compared to that of day 3.
In the experimental groups and control, 3% to 6% of sperm motility was maintained until day
40. Even by 40 days post ligation, 11.6 ± 4.2% of live spermatozoa were found (Dead
spermatozoa, 88.3% ± 19.8). When the sperm morphology of cauda was considered the
normal sperm percentage was about 24% in treatment groups and it varied significantly
(P < 0.001). By the day 32 post ligation, 76% of cauda spermatozoa were abnormal with head
defects, mid piece and neck defects, tail defects, headless, tailless and multiple defects.
Fertilization ability of hamster sperm after cauda ligation, was investigated using in vitro
fertilization technique. For in vitro fertilization, the sperm concentration for insemination was
kept between 5 x 105 and 1 x 106 sperms/ml per 20 - 30 eggs. Even though high percentage of
oocytes was fertilized in the control group (90% - 100%), it was found that the fertilizing
ability of spermatozoa was decreased to 70% in 24 day of post ligation. Ca ionophore
(A23187) was used to induce capacitation and acrosome reaction of hamster sperm in
different post ligation days and the Chlortetracycline (CTC) assay was used to asses the
capacitation and acrosome reaction of the induced hamster spermatozoa. The CTC results
revealed that Ca ionophore A 23187 was effective to promote sperm capacitation and
acrosome reaction even at 48 days after ligation of hamster cauda epididymis.