Prenatal protein deprivation increases defects of the corpus callosum in BALB/c laboratory mice.

The development of two forebrain fiber tracts, the anterior commissure (CA) and corpus callosum (CC), was examined in BALB/cCF laboratory mice in relation to the maternal dietary protein concentration during gestation. The diets contained either 8 or 27% casein. The BALB/c strain was used because it is prone to having a corpus callosum which is either deficient in size or absent. Female mice were assigned to the low-protein diet either 2 weeks prior to mating (chronic malnutrition) or on the seventh day of gestation (acute malnutrition), and fetal brain development was assessed at 18.5 days after conception. Protein deficiency increased the number of animals which did not have a corpus callosum present in a midsagittal section. In those animals in which the structure was present, it was evident that the cross-sectional area was smaller in the chronically deprived animals than in the control group. In addition to CC area, both CA area and brain weight were reduced by protein deprivation. When brain weight was used as a covariate in an analysis of covariance the effect on CA area was no longer apparent. Part of the effect on the corpus callosum was, however, independent of the effect on brain weight and CA area.