[The effects of L-tryptophan and pentoxiphylline on stress ulcer]. / L-triptofan ve pentoksifilinin stres ulseri uzerine etkisi.

BACKGROUND: It is well known that stress leads to the formation of gastric mucosal lesions. Free oxygen radicals play an important role in the pathogenesis of inflammation and tissue damage. It was observed that L-tryptophan has a positive effect on gastric mucosal damage in ischemia-reperfusion injury by inhibition of free oxygen radicals. The protective effect of pentoxifylline was shown in gastric mucosal damage induced by ischemia - reperfusion or the application of some topical agents. We performed an experimental study to determine whether intragastric L-tryprophan and intramuscular pentoxifylline protect gastric mucosal damage that is induced by immobility stress. METHODS: Forty rats were immobilized and divided into four groups. No treatment was made in the first group; in group 2,3 and 4, L-tryptophan, pentoxifylline and L-tryptophan + pentoxifylline were administered, respectively. The gastric lesions were assessed macroscopically and microscopically two hours following treatment. RESULTS: In the second and fourth groups, the lesion surface area and average mucosal damage were fewer in comparison to the control group (p<0,03). Moreover, an histopatologically improvement in the surface epithelium was observed in these groups. The average lesion score also reduced significantly (p<0,03) only in the L-tryptophan group. On the other hand, no statistically significant improvement was observed in the pentoxifylline group. CONCLUSION: As a result, it was concluded that L-tryptophan could play a protective role in the gastric mucosal damage associated with stress.

Effects of melatonin and lactulose on the liver and kidneys in rats with obstructive jaundice.

The negative effects of obstructive jaundice (OJ) on the liver and kidneys cause high morbidity and mortality. In this study, the effects of melatonin (M) and lactulose (L) on the liver and kidneys were investigated by inducing OJ in 30 rats in five groups (n = 6): controls, sham, M, L, and M + L. In the treatment group, after the rats' biliary canals were tied and cut, 10 mg/kg M IM and 2 ml/day L p.o. was administered for 7 days. The histopathologic findings in the liver and kidneys, tissue malonyl dialdehyde (MDA) levels, and serum biochemistry were evaluated. In the M group, pathological histologic findings were less marked than in the other groups; investigation of kidney cross-sections revealed no significant differences among groups. In the jaundiced rats liver MDA levels were significantly higher compared to the control group ( P < 0.001), but no such difference was observed in kidney MDA levels ( P > 0.05). L did not cause any significant changes in tissue MDA levels. There were no differences among groups with regard to serum levels of liver enzymes and bilirubin. Serum urea was significantly less in the group that received L ( P < 0.001), but the groups showed no significant differences with respect to creatinine values ( P > 0.05). The increase in serum total cholesterol was significantly less in the M + L group than in the other groups ( P < 0.001). We conclude that in the rats in which obstructive jaundice was induced, M administration reduced liver and kidney injury, but L and M + L did not lead to significant improvement.