Fx. Jiang et al., POSTNATAL DIFFERENTIATION AND DEVELOPMENT OF THE RAT EPIDIDYMIS - A STEREOLOGICAL STUDY, The Anatomical record, 238(2), 1994, pp. 191-198
Postnatal development and differentiation of the rat epididymis was st
udied in the rat from 15 to 120 days of life using stereological techn
iques. Both the relative volume (volume density) and absolute volume o
f the epithelial, interstitial, and luminal compartments in the initia
l segment, caput, corpus, and cauda epididymides were determined. In a
ll segments the volume density of the epithelial compartment increased
between days 15 and 30 before falling to adult values at 45 days in t
he initial segment (0.476 +/- 0.031), at 60 days in the caput (0.258 /- 0.028) and at 90 days in the corpus (0.245 +/- 0.007) and cauda (0.
140 +/- 0.004). The relative volume of the interstitium decreased, whi
lst that of the lumen increased over the same period with adult values
being achieved earlier in the proximal segments than in the distal se
gments. In contrast to volume fraction the absolute volume of all comp
artments in all segments increased from day 15 to day 90. Between 90 a
nd 120 days the absolute volumes of compartments in the initial segmen
t and caput showed little volume change. All compartments in the corpu
s and cauda showed significant increases in volume over the same perio
d. A similar pattern of development was observed with respect to the s
urface area of both the luminal and basement membrane aspects of the e
pithelium; surface area per unit volume (surface density) in all segme
nts reached adult values at approximately 60 days, whilst the increase
in absolute area of the surfaces ceased at 90 days in the initial seg
ment and caput and continued to 120 days in the corpus and cauda. The
total length of the epididymal tubule showed the same pattern with no
increase in length apparent in the initial segment and caput after 90
days. Length however continued to increase in the corpus and cauda bet
ween 90 and 120 days. Tubule and luminal diameter reached their defini
tive values in the initial segment on day 60 but continued to increase
until day 90 in the distal segments. Epithelial height increased betw
een 15 and 30 days in all segments; in the caput, epithelial height wa
s greatest on day 30 before decreasing slightly; and in the corpus and
cauda maximal epithelial height was observed on day 45 decreasing to
stable values on day 60 and 90, respectively. All the data is consiste
nt with a proximal to distal differentiation and development of the ep
ididymis with growth continuing in all segments after the establishmen
t of the definitive architecture. Growth of the distal segments contin
ued after its cessation in the proximal segments. (C) 1994 Wiley-Liss,
Inc.