Effect of low protein diet on manganese neurotoxicity: I. Developmental and biochemical changes

The first in a series of studies on the effect of concurrent low protein diet (10% casein) and manganese exposure (Mn2+, 3 mg/ml drinking water) in rats is reported here. The effect on growing (Fo-90 days) rehabilitated (Fo low leads to normal protein diet-28 days) and the F1 generation pups (weaned) were studied. Mn2+ exposure had no significant effect on growth pattern, brain weight or brain and plasma protein contents in either dietary groups. The diet regimen had no significant effect on the accumulation of Mn2+ in brain in any of the groups studied but the levels were higher in the F1 pups than in the parent (Fo) generation. In the F1 pups Mn2+ exposure had no effect on eye opening in either dietary group, delayed the development of startle reflex in low protein fed group only but the air righting reflex development was delayed in both the dietary groups, the effect being more marked in the low protein fed group. These changes reflect the early neurotoxic effect of Mn2+.