Abstract:
The mammalian epididymis is a highly convoluted tubule, which can be divided into several
regions depending either on its functional capability or its morphology, Epididymal duct is
narrow and long. It is lined by a pseudostratified epithelium and in general the tubule
diameter increases from the caput to the cauda. The absorptive and secretory activities of the
epididymis are performed by the epithelium of the epididymis and this is therefore the
functional unit of the epididymis, Epithelium of the epididymis is active with synthesis and
secretion of various proteins and constituents that promote sperm maturation. However,
significance of the morphological variations and sperm motility has not been studied
previously. Objective of the present investigation was to study morphological variations and
functional maturation of sperm in the epididymis of rat. Rat epididymis were isolated and
total sperm number, sperm motility were recorded using mammalian saline as the medium.
Tissue samples were fixed in Bouin's and histology was carried out. Epididymal duct
diameter (mm) and epithelium width (mm) measured. Data were statistically analyzed.
According to the data tubule diameter of the duct increases from caput region (0.233 ±
0.002) to the cauda region (0.299 ± 0.002). However, tubule epithelium thickness decreases
from capiat region (0.030 ± 0.007) to the cauda region (0.918 ± 0.003). Results were
significant (P<0.05) with compared to data from caput region. Since the concentration of
sperm also varies from proximal to the distal end of the epididymis (937x106 in caput to
1670x10° in distal cauda; PO.QOi) it is clear that increase in diameter is mainly to
accommodate more sperm. Cauda epididymis is more important in the storage of sperm.
During this time, sperm remain viable in a quiescent state and their membranes are
protected. Nevertheless, sperm motility increases while they pass through the epididymis.
Whether this motility is purely depend on services from the epididymal epithelium or
whether it is due to another fact is not clear from the present findings, However, evidence of
the present study shows that morphology of rat epididymis has a relation to the development
of sperm motility.