Malnutrition increases NO production and induces changes in inflammatory and oxidative status in the distal colon of lactating rats.

Abstract

Epidemiological studies have indicated the lack of breast feeding as a risk factor associated with later development of inflammatory bowel disease. Nevertheless, the repercussion of little feeding during suckling on large intestine inflammatory response and anti-oxidant resources has not yet been completely understood. This study hypothesized that unfavorable lactation is able to induce oxidative stress and release of inflammatory mediators modifying the integrity of the colon epithelium in weanling rats. Wistar rats were reared under different early nutritional conditions according to litter size in two groups: N6 (6 pups/dam) and N15 (15 pups/dam) until the 25th postnatal day. The distal colon was removed and processed for biochemical, morphometric, and immunohistochemical analyzes. Lipoperoxidation, nitric oxide (NO), reduced (GSH) and oxidized (GSSG) glutathione, tumor necrosis factor-alpha (TNF-α), interleukins-1β, 4 and 10 (IL-1β; IL-4; IL-10) levels, and total superoxide dismutase (tSOD), and catalase (CAT) activities were assessed. Morphometric analysis was carried out using paraffin sections and wholemount myenteric plexus preparations. Increased lipoperoxidation, NO, TNF-α and IL-1b levels, reduced tSOD and increased CAT activities were found in the N15 compared to N6 group. No intergroup difference was detected for IL-10, while lower levels of IL-4, GSH and GSSG and lower neuronal size and density were induced by undernutrition. Reduced feeding during suckling changed the inflammatory response and oxidative status in the colon of weanling rats. These data suggest potential mechanisms by which malnutrition early in life may increase the vulnerability of the large intestine to insults.