This study provides quantitative information on the effect of sodium fluori
de (NaF) on the testes of F-1 generation male rats exposed in utero and dur
ing lactation to NaF at one of Four concentrations (25, 100, 175, 250 ppm).
At weaning, the F-1 generation males were exposed to NaF in their drinking
water for 14 weeks, after which time testicular tissues were perfusion-fix
ed with glutaraldehyde and observed after being embedded in plastic. The se
miniferous tubules comprised 89%, 87%, 88%, 88% and 88% of the total testis
volume while the interstitial space occupied 9.3%, 11.2%, 10.2%, 9.8% and
9.9% of the total testis volume for the 0, 25, 100, 175 and 250 ppm NaF tre
atment groups, respectively. Statistically significant differences between
control and NaF-treated rats were not observed with respect to absolute vol
ume of the seminiferous tubules, interstitial space, Leydig cells, blood ve
ssels boundary layer, lymphatic space, macrophages, tubular lumen or absolu
te tubular length and absolute tubular surface area, mean Sertoli cell nucl
eoli number per tubular cross-section, mean seminiferous tubule diameter an
d the mean height of the seminiferous epithelium. A statistically significa
nt decrease in the absolute volume and volume percent of the lymphatic;endo
thelium was observed in the 175 and 250 ppm NaF-treated groups and in the t
esticular capsule in the 100 ppm NaF-treated groups. The significance of th
is finding is unknown at the present time. Overall, the quantitative inform
ation obtained suggests that exposure to NaF at the doses used in the prese
nt study does not adversely affect testis structure or spermatogenesis in t
he rat. (C) 1998 Elsevier Science Ltd All rights reserved.