Dietary restriction interferes with oxidative status and intrinsic intestinal innervation in aging rats.

Objectives: To evaluate the effects of dietary restriction on oxidative status, the HuC/D-neuronal nitric oxide synthase (nNOS) myenteric neuron population, HuC/D-S100 glial cells, and the morphometry of the small intestine in rats at various ages.

Methods: Fifteen Wistar rats were divided into 7-and 12-mo-old control groups and a 12-mo-old experimental group subjected to dietary restrictions (50% of normal ration) for 5 mo. At 7 and 12 mo of age, the animals were anesthetized, and blood was collected to assess the biochemical components and oxidative status. Ileum samples were subjected to double-marker (HuC/D-nNOS and HuC/D-S100) immunostaining and histologic processing to morphometrically analyze intestinal wall elements and determine the metaphase index and rate of caliciform cells. The data were subjected to analysis of variance and the Tukey post hoc test with a 5% significance level.

Results: Age affected the oxidative status by increasing lipid peroxidation, with no effect on blood components, intrinsic innervation, and intestinal wall elements. The animals subjected to dietary restriction showed improved levels of total cholesterol, triacylglycerols, and oxidative status, with no changes in the nNOS neuron population. However, the dietary restriction dramatically decreased the glial and HuC/D myenteric populations, led to atrophy of the neuronal cell body, induced glial hypertrophy, and decreased the thickness of the intestinal wall.

Conclusion: The high oxidative status of the aging animals was reversed by dietary restriction, which also lowered cholesterol and triacylglycerol levels. The present dietary restriction elicited morpho-quantitative changes in the myenteric plexus and histology of the ileum, with likely effects on intestinal functions.