Biomedical Engineering Reference
In-Depth Information
exposure to 3.1mg/ml after the final exposure. Offspring body weight
was reduced by about 5% on PND 1, but the behavioral tests used,
including motor activity (PND 13-21, 30, 60), olfactory learning (PND
18), behavioral thermoregulation (PND 20-21), T-maze learning (PND
23-24), acoustic startle response (PND 24, 60), reflex modification
audiometry (PND 60), passive avoidance (PND 72), and visual-evoked
potentials (PND 160) did not detect any difference between methanol-
exposed and control groups.
The effects of methanol exposure during early pregnancy in the rat
were studied by Cummings (1993). Rats were dosed orally with up to
3.2 g/kg/day methanol on GD 1-8 and groups of animals were killed on
GD 9, 11, or 20. The decidual cell response (DCR) technique, in which
the lining of the uterus is surgically stimulated to induce proliferation,
was also applied. Reductions in pregnant uterus weight and implanta-
tion site weights were observed on GD 9 and effects on the DCR
suggested that methanol impeded uterine decidualization. No other
effects on viability or development of conceptuses were noted.
5.3.2 Mice
Rogers et al. (1993) studied the effects of methanol exposure (1000,
2000, 5000, 7500, 10,000, 15,000 ppm) during pregnancy in CD-1 mice
under conditions similar to those used for rats by Nelson et al. (1985).
No maternal toxicity was attributed to methanol although the exposure
procedure per se reduced maternal weight gain in all groups, including
the filtered air-exposed mice, compared to unhandled controls. An
additional unexposed control group was food-deprived for 7 hour/day
similar to the food deprivation experienced by the exposed groups.
Food-deprivation accounted for some, but not all, of the effect of
exposure on maternal weight. CD-1 mice were found to be more
sensitive to the developmental toxicity of methanol than were
Sprague-Dawley rats. Cleft palate, exencephaly, and skeletal defects
were observed at 5000 ppm and above. The incidence of fetuses with
ribs on the seventh cervical vertebra was increased in a dose-related
fashion at 2000 ppm and above. The skeletal anomalies observed,
including cervical vertebral anomalies and cervical ribs, were similar
