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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.

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Introduction: Methionine is an essential sulfuric amino acid, which, according to numerous studies, has a role in the reduction of inflammation, caused by changes in colon, and inhibits important pathways in the development of numerous gastrointestinal disorders. However, subchronic methionine loading leads to oxidative stress, which is a potential cause of disease of numerous organs, digestive tract being one of them. N-acetyl-L-cysteine is a natural antioxidant, which affects some of the important signaling pathways and has a potential therapeutic role in treatment of colon disorders. Aim: To examine the influence of N-acetyl-L-cysteine on histological parameters of rat colon, after subchronic methionine load. Material and methods: Experiments were conducted on 15-20 days old male (Wistar albino) rats, weighing 160 g. There were used 24 animals in the experiment, divided into 3 groups, with eight animals per group. First, control group (K), received NaCl, second group received methionine (M group), while third group received methionine + N-acetyl-L-cysteine (N group). The rats were sacrificed after 21 day and tissue samples of colon were obtained. In all of the three groups, changes of histological parameters of rat colon were analyzed. Results: Methionine load leads to statistically significant increase (p < 0.01) in crypt depth of rat colon, lamina muscularis mucosae thickness, the mucosal thickness and increase in lamina propria cell density compared to control, while N-acetyl- L-cysteine application showed statistically significant decrease (p < 0.01) of these histological parameters compared to M group. Conclusion: N-acetyl-L-cysteine has a significantly protective effect on methionine load induced changes in rat colon.

This study was conducted to explore the effects of sulfur containing amino acids on redox status and morphological parameters in the rat ileum tissue. Male Wistar albino rats were randomly divided into the following groups: K group (saline, 1 ml/day, i.p.), M group (methionine, 0.8 mmol/ kg/day, i.p.), C group (methionine (0.8 mmol/kg/day) + L-cysteine (7 mg/kg/day), i.p.) and N group (methionine (0.8 mmol/kg/day) + N-acetyl-L-cysteine (50 mg/kg/day), i.p.). Activities of antioxidant enzymes in the ileum were analyzed to profile oxidative status. Morphometric analysis included measurement of villus height (µm), tunica mucosa thickness (µm), tunica muscularis thickness (µm), the total thickness of the ileal wall (µm) and the number of cells in the lamina propria (per 0.1 mm² of tissue). Results showed that methionine treatment reduced the activity of antioxidant enzymes (SOD, GPx, CAT) and the GSH content compared to the control group (p > 0.05). The application of methionine reduced the following parameters statistically significant compared to the control group: length of the ileal villi (p < 0.01), tunica mucosa thickness (p < 0.01), and ileal wall thickness (p < 0.01). We concluded that methionine induced the changes in the gut redox status, which implied oxidative stress occurrence. L-cysteine and N-acetyl-L-cysteine both exhibited antioxidant properties. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]