Biomedical Engineering Reference
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skeletal and cardiovascular effects (Nelson et al., 1985; NEDO, 1987).
In contrast, Holtzman rats exposed to a range of MeOH doses by gavage
(1.6-3.2 g/kg bw) exhibited no significant embryonic or fetal effects
with treatment (Cummings, 1993). Long-Evans rats, unlike the afore-
mentioned strains, exhibited ophthalmic abnormalities and abnormal
development of sexual organs when exposed to a range of MeOH doses
by gavage (1.3-5.2ml/kg or 1023-4090mg/kg bw according to the
Center for the Evaluation of Risks to Human Reproduction (CERHR)
calculations (NTP, 2002)) on GD 10 (Youssef et al., 1997). Among
mouse strains, CD-1 mice exhibit cephalic neural tube defects (NTDs)
with the highest incidence, along with facial and palatal clefts and
skeletal defects (Bolon et al., 1994). C57BL/6 mice, on the other hand,
primarily exhibit ophthalmic abnormalities, including microphthalmia
(smaller eyes) and anophthalmia (absence of the eye), along with facial
and palatal clefts and skeletal defects (Rogers et al., 2004). Overall,
C57BL/6 mice are more susceptible to the effects of in utero MeOH
exposure, displaying a much higher incidence of affected pups per litter,
more than twice that observed in CD-1 mice. The periods of suscepti-
bility among strains are similar, however, with MeOH administration on
GD 7 or 8 resulting in the highest incidence of affected pups.
Comparing the potency of MeOH to the related alcohol, EtOH, in
whole embryos of various strains of mouse exposed in culture for
24 hours, for some developmental parameters there is no distinct
difference in embryopathies caused by these two alcohols at a similar
molar concentration. However, for other parameters, it appears that
EtOH reduces anterior neuropore closure, turning and somite develop-
ment by 50mM while MeOH reduces these parameters at or above
100mM, suggesting EtOH is more potent (Figure 7.15). In rat embryos,
EtOH appears to be more potent than MeOH, as EtOH reduces crown-
rump length, head length, somite development, and protein content by
50-100mM, while MeOH reduces these parameters at or above
100mM (Figure 7.16). Some outcomes assessed in the same strain
by the same lab exhibited differences, as observed with protein content
measured in Sprague-Dawley rat embryos (Figure 7.16). There are no
remarkable species differences between mouse and rat embryos
exposed to MeOH for 24 hours in culture except for embryolethality,
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