Effects of subchronic methionine stimulation on oxidative status and morphological changes in the rat ileum.

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: Group K (saline (1 ml/day, i.p.)), Group M (methionine (0.8 mmol/kg/day, i.p.)), Group C (methionine (0.8 mmol/kg/day) + L-cysteine (7 mg/kg/day), i.p.) and Group N (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.

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.

[Possible inhibitory effect of nitric oxide donor, dipropylenetriamine nonoate (DPTA/NO), on oxygen consumption of isolated rats' testis interstitial cells].

INTRODUCTION: The understanding of testicular physiology, pathology, and male fertility issues requires knowledge of male germ cell death, energy production and oxygen consumption. The aim of this study was to examine the effect of a new donor of exogenous nitric oxide, di-propylen-three amin-NONOate (DPTA/NO), on the oxygen consumption by freshly isolated rats' testis interstitial cells. MATERIAL AND METHODS: Rats' testis interstitial cells (ISC) were isolated according to Anakwe method and oxygen consumption was measured in an ex vivo bath. The ISC were stimulated with glutamate (0.5 M, 20 microl). DPTA (10(-3) - 10(-6) M) was added and its effect was tested in the absence of ADP (state 4 of respiration) and after that in the presence of ADP (state 3). The reaction was followed for 10 minutes and for each concentration the measurement was done in duplicate. The same measurements without treatment of DPTA/NO were done for control group. RESULTS: DPTA/NO (10(-4) - 10(-6) M) reduced the oxygen consumption rate compared with the control group. The inhibition of respiration was not noticed in concentration of 10(-3) M. In V3 respiratory phase, all tested concentrations of DPTA/NO (10(-3) - l0(-6) M) decreased the oxygen consumption rate in comparison with the control group. CONCLUSION: Our results demonstrate that a NO donor, DPTA/NO (10(-3) - 10(-6) M) inhibits oxygen consumption in isolated rat testis interstitial cells in a manner that could be concentration dependent. Because of limited number of measurements this was not fully proved and additional experiments are needed.

Properties of thiamine transport in isolated perfused hearts of chronically alcoholic guinea pigs.

The aim of this study was to determine the mechanism of transport of (14)C-thiamine in the hearts of healthy (nonalcoholic) and chronically alcoholic guinea pigs. We used the single-pass, paired-tracer dilution method on isolated and retrogradely perfused guinea pig hearts. The maximal cellular uptake (U(max)) and total cellular uptake (U(tot)) of (14)C-thiamine were determined under control conditions and under influence of possible modifiers. We tested how the presence of unlabeled thiamine, metabolic inhibitors, or absence of sodium ions influence the transport of (14)C-thiamine. The results of our experiments show that the transport of (14)C-thiamine is specific and energy-dependent and that its properties are significantly changed under the influence of chronic alcoholism. The latter effect occurs by increase in both U(max) and U(tot), as a manifestation of a compensatory mechanism in thiamine deficiency.