Effect of vitamin supplementation on cisplatin-induced intestinal epithelial cell apoptosis in Wistar/NIN rats.

OBJECTIVE: Chemotherapeutic agents induce small intestinal mucositis that is characterized structurally by crypt loss and villus atrophy and functionally by absorptive and barrier impairments. We studied the effect of selected individual vitamins and multiple-vitamin mixture supplementation in modulating cisplatin-induced intestinal damage and apoptosis. METHODS: Thirty-six male Wistar/NIN rats 20 wk old and fed the control diet (AIN-93G) were randomly divided into six groups. Five groups were administered cisplatin (2.61 mg/kg of body weight) once a week for 3 wk and were concomitantly provided the control diet or riboflavin, folate, α- tocopherol, or a multiple-vitamin mixture supplemented diet. The sixth group served as a control for cisplatin and received saline as the vehicle. Intestinal epithelial cell apoptosis was monitored by morphometry, M30 staining, DNA fragmentation, and caspase-3 activity. Functional and structural integrities were determined by measuring activities of alkaline phosphatase and lysine ala-dipeptidyl aminopeptidase and the villus height/crypt depth ratio. Oxidative burden was assessed as the formation of thiobarbituric acid-reactive substances and protein carbonyls. Plasma levels of selected vitamins were also measured. RESULTS: Cisplatin administration significantly increased intestinal apoptosis in the villus and crypt regions that correlated with increased oxidative damage, decreased Bcl-2/Bax, and compromised functional integrity. Riboflavin, folate, and the multiple-vitamin mixture supplementation attenuated the cisplatin-induced increase in apoptotic indices, with a decrease in oxidative burden, increased Bcl-2/Bax, and improved functional and structural integrities. The α-tocopherol supplementation, although effective in attenuating oxidative stress and improving functional integrity, failed to lower the apoptotic indices. CONCLUSIONS: Riboflavin, folate, and the multiple-vitamin supplementation proved to be more efficacious in attenuating the cisplatin-induced intestinal damage and associated changes in apoptosis.

Chronic low intake of protein or vitamins increases the intestinal epithelial cell apoptosis in Wistar/NIN rats.

OBJECTIVE: Malnutrition decreases antioxidant defense and increases oxidative stress in the intestine. We studied the effects of long-term restriction of food, protein, and vitamins on intestinal epithelial cell (IEC) apoptosis and the underlying mechanisms. METHODS: Weanling, Wistar/NIN male rats were fed ad libitum with a control diet, 75% protein-restricted diet, or 50% vitamin-restricted diet for 20 wk. The food-restricted group received 50% of the diet consumed by control rats. IEC apoptosis was monitored by morphometry, Annexin V binding, M30 CytoDeath assay, and DNA fragmentation. Structural and functional integrity of the villus were assessed by the ratio of villus height to crypt depth, and alkaline phosphatase and lys, ala-dipeptidyl aminopeptidase activities, respectively. Oxidative stress parameters, caspase-3 activity, and expression of Bcl-2 and Bax were determined to assess the probable mechanisms of altered apoptosis. RESULTS: Protein and vitamin restrictions but not food restriction significantly increased IEC apoptosis and only vitamin restriction altered structural and functional integrity of villi. Increased levels of protein carbonyls, thiobarbituric acid reactive substances, and caspase-3 activity along with decreased glutathione levels and Bcl-2 expression were observed in IECs of these rats, whereas food restriction did not affect these parameters. CONCLUSIONS: Protein restriction increased only IEC apoptosis, whereas vitamin restriction also affected the structure and function of villi. Modulation of the pathway mediated by mitochondria through increased oxidative stress appears to be the probable mechanism underlying this effect.