M. Horimoto et al., Rat epididymal sperm motion changes induced by ethylene glycol monoethyl ether, sulfasalazine, and 2,5-hexandione, REPROD TOX, 14(1), 2000, pp. 55-63
Epididymal sperm was examined using the Hamilton-Thorne Sperm analyzer (HTM
-IVOS, version 10.6) in male rats treated with known male reproductive toxi
cants that act by different mechanisms to detect effects on sperm motion. T
hree agents known to produce changes in sperm motion at high exposure level
s were administered at lower levels. Ethylene glycol monoethyl ether (EGEE)
, sulfasalazine (SASP), and 2,5-hexandione (2,5-HD) were administered by or
al gavage to adult male Sprague-Dawley rats at 250 or 500 mg/kg/day, at 300
or 600 mg/kg/day, or at 100 or 250 mg/kg/day, respectively. The males were
treated with EGEE, SASP, and 2,5-HD for 35, 28, and 28 days, respectively.
The males treated with EGEE and SASP were mated with untreated females to
assess male fertility. All males were examined for body weight, testicular
and epididymal weight, epididymal sperm count, and sperm motion. The sperm
motion parameters included percentage of motile sperm, percentage of progre
ssively motile sperm (progressive motility), curvilinear velocity (VCL), av
erage path velocity (VAP), straight line velocity (VSL), amplitude of later
al head displacement (ALH), beat cross frequency (BCF), linearity (LIN), an
d straightness (STR). For the male rats treated with SASP, no treatment-rel
ated effects on percentages of motile sperm or sperm count were observed de
spite impaired male fertility. However, abnormal motion of epididymal sperm
from the SASP treated males was detected by a significant reduction in mea
n progressive motility, VAP, and ALH, and an increase in BCF and STR. For t
he males treated with 2,5-HD for 4 weeks, most parameters generated by the
HTM-IVOS indicated decreased sperm motion despite no remarkable changes in
testicular weight, epididymal weight, or sperm count. In the EGEE-treated m
ales at 250 mg/kg/day for 5 weeks, abnormal motion of epididymal sperm was
detected by decreased progressive motility and increased BCF, although ther
e were no treatment-related effects on testicular weight or male fertility.
Progressive motility was decreased in all treated groups and the differenc
e from the control value was of the greatest magnitude among the sperm moti
on parameters generated by the HTM-IVOS. Velocity parameters (VAP, VSL, VCL
) responded sensitively to abnormal sperm motion in the SASP and 2,5-HD stu
dies. In spite of decreased sperm motion, BCF values were significantly inc
reased in all treated groups except the 7-week EGEE high-dose group, where
there were no motile sperm to evaluate. ALH was significantly decreased in
the treated groups in which remarkable effects on sperm motion were noted.
There were no significant changes in ALH at the low-dose of EGEE at which o
nly mild effects on sperm motion were observed. STR was increased for epidi
dymal sperm from the males treated with SASP when compared with the control
s. For the males treated with EGEE and 2,5-HD, however, STR was decreased w
hen compared with the controls. There were no significant differences in LI
N in any of the groups treated with SASP, in which remarkably reduced sperm
motion was detected by the other parameters. In conclusion, among the para
meters generated by the HTM-IVOS, progressive motility was significantly de
creased in all treated groups and the most valuable for detecting slight ch
anges in sperm motion induced by these three different target toxicants. Fu
rther investigation with a larger set of compounds is needed to evaluate wh
ich NOS parameters are the most sensitive in detecting motion changes. (C)
2000 Published by Elsevier Science inc. All nights reserved.