Effects of folic acid intake on plasma folate, vitamin B12 and homocysteine levels, hepatic SAM/SAH ratio and the expression of cerebral myelin basic protein in pregnant and lactating rats

Abstract

The effect of folate nutrition during gestation on the development of offspring's brain has been extensively studied, but that on the maternal brain remains mostly unknown. To investigate this, female Sprague‐Dawley rats were fed either folic acid supplemented (FS)‐ or deficient (FD)‐diet (8mg vs. 0mg folic acid/kg diet) from 2 weeks prior to the mating throughout the pregnancy and lactation period. At d20 of pregnancy and d21 of lactation, plasma folate levels and hepatic SAM/SAH ratios of the FD group were significantly lower than those of the FS group (p<0.001) with a concomitant change in the plasma homocysteine level (p<0.001). Plasma vitamin B12 level of the FD group was significantly lower than that of the FS group at d21 of lactation (p<0.01). At d20 of pregnancy, the MBP expression in the spinal cord, but not in cerebral cortex or hippocampus, was higher than that of pre‐pregnancy in all groups with a greater increase occurring in the FS group than the FD group. Plasma folate and vitamin B12 level was correlated with hepatic SAM/SAH ratio positively and with homocysteine negatively. The expression of MBP in the spinal cord, but not in cerebral cortex or hippocampus, was positively correlated with hepatic SAM/SAH ratio. These results indicate that the expression of MBP in the spinal cord of maternal rats is influenced by the hepatic SAM/SAH ratio and indirectly by dietary folic acid intake.