Suppression of methionine-induced colon injury of young rats by cysteine and N-acetyl-l-cysteine

Changes in the methionine metabolism can cause a state called hyperhomocysteinemia, inducing oxidative stress in the gut. The production of free radicals is important in the colon damage caused by methionine. This study aimed at evaluating the effect of the use of l-cysteine and N-acetyl-l-cysteine on the colon morphometry of young rats treated with methionine. A total number of 32 male rats were distributed in a randomized experimental design in 4 groups: control group treated with saline; methionine group; cysteine + methionine group, and N-acetyl-l-cysteine + methionine group. After 21 days of treatment, rats were sacrificed and the colon samples were taken for histological and biochemical analysis. Methionine load increased depth of crypts, the lamina muscularis mucosae thickness, the mucosal height, and the number of cells in lamina propria (p < 0.01). Combination of methionine with l-cysteine (C group) and with N-acetyl-l-cysteine (N group) reversed methionine effects. Methionine treatment increased the GPx activity and MDA concentration, while l-cysteine and N-acetyl-l-cysteine increased the catalase activity compared to methionine group. It was concluded that the use of l-cysteine and N-acetyl-l-cysteine was beneficial to decrease intestinal mucosal height and oxidative damage when methionine was used in combination with them.