The effects of ageing and a vitamin E-deficient diet on the lipopigment content of rat hippocampal and Purkinje neurones

Abstract

This study examined associations between a vitamin E-deficient diet, ageing and aspects of the morphology of neuronal lipopigment in rat hippocampal and Purkinje neurones. Groups of rats given a standard diet were killed at 6, 12, 18 and 25 months of age, while a group which had received a vitamin E-deficient diet from 1–18 months were killed at 18 months of age. Lipopigment within a neuronal cell body consists of a number of discrete regions of varying size. These were identified by fluorescence microscopy and a photograph for each individual neurone was projected onto paper, so that the outlines of the discrete regions of lipopigment could be drawn and subjected to morphometric measurements. Both ageing and vitamin E deficiency in relation to hippocampal neurones and vitamin E deficiency in relation to Purkinje neurones (in which ageing effects were not examined), were associated with a significant (< 0.05) increase in the mean total area (per rat) enclosed by the lipopigment outlines. For both vitamin E deficiency and ageing this increase was associated with both an increase in the number of relatively large discrete lipopigment regions and a decrease in the number of relatively small discrete lipopigment regions. The findings in relation to vitamin E deficiency could be explained by an increased rate of lipopigment formation, involving processes which also occur in ageing.