Irinotecan-Induced Skin Dryness Is Ameliorated By Orally Administered High-Dose Vitamin C In Mice.

BACKGROUND: Vitamin C plays a part in various roles in the human body. In this study, we examined the effect of oral administration of high-dose vitamin C on the skin dryness induced by irinotecan. METHODS: To establish the experimental model of irinotecan-induced skin dryness, the drug was intraperitoneally administered for four consecutive days. Simultaneously, oral administration of high-dose vitamin C (4 g/kg) was continued for 4 days. RESULTS: High-dose vitamin C administration ameliorated the skin dryness induced by irinotecan. The expression of caspase-3 and caspase-9, reactive oxygen species, and the number of TUNEL-positive cells increased in the skin of irinotecan-treated mice but were lowered by high-dose vitamin C administration. In contrast, fibroblasts and collagen type I decreased in the skin of the irinotecan-treated mice but was increased by high-dose vitamin C administration. CONCLUSION: These results suggested that high-dose vitamin C administration can improve the skin dryness induced by irinotecan.

Ameliorative Effect of High-Dose Vitamin C Administration on Dextran Sulfate Sodium-Induced Colitis Mouse Model.

Vitamin C is a natural nutrient with antioxidant properties and is used as a health supplement. In this study, we examined the effects of intraperitoneal administration of high-dose vitamin C (4 g/kg) on dextran sodium sulfate (DSS)-induced ulcerative colitis. We prepared a mouse ulcerative colitis model by administering DSS for 7 d along with high-dose vitamin C each day during DSS treatment. Ulcerative colitis induced by DSS was ameliorated by high-dose vitamin C administration. Blood levels of interleukin-6, tumor necrosis factor-α, hydrogen peroxide (H2O2), and iron were elevated in DSS-treated mice but lowered by high-dose vitamin C administration. Contrarily, the levels of H2O2 and iron and the numbers of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)-positive cells in the colon were further increased by high-dose vitamin C administration. The expression levels of fibroblasts, collagen type I, and collagen type III decreased in the DSS-treated mice but increased in mice administered high-dose vitamin C. These results suggest that high-dose vitamin C administration can improve ulcerative colitis.

Administration of High-Dose Vitamin C and Irinotecan Ameliorates Colorectal Cancer Induced by Azoxymethane and Dextran Sodium Sulfate in Mice.

High-dose vitamin C administration has been reported to exhibit antitumor effect in various mouse models of cancer. However, the underlying mechanism of antitumor effect against colorectal cancer remains to be elucidated. In this study, we investigated the antitumor effect of high-dose vitamin C in a mouse model of chronic inflammation-associated colorectal cancer induced by azoxymethane (AOM) and dextran sodium sulfate (DSS). After cancer induction, the mice were administered vitamin C and/or irinotecan. Because irinotecan is a key drug in colorectal cancer treatment, it was used for comparison in this study. We examined reactive oxygen species (ROS) and interleukin-6 (IL-6) levels in the plasma of mice, as well as collagen type I and caspase-1 expression and neutrophil and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)-positive cell counts in the colon tissue. Vitamin C and/or irinotecan administration decreased the plasma level of ROS and IL-6 and increased the expression of collagen type I and caspase-1. Furthermore, it increased neutrophil and TUNEL-positive cell counts. The most significant changes in the parameters analyzed were observed when both vitamin C and irinotecan were administered.