Protective Effect of Vitamin A on Methotrexate Induced Micronuclei

Methotrexate is an antineopalstic agent widely used in low dose to treat patients with rheumatoid arthritis. It is known to induce micronuclei at multiple doses in rats. The present study investigates the effect of vitamin A on methotrexate-induced micronuclei in rat bone marrow erythrocytes. Male wistar rats were (n=5) injected with 0, 8, 16 and 20mg/kg methotrexate (single i.p dose). A group of rats received 5000 IU of vitamin A (i.p) for 4 successive days. Another group of rats received a combination of vitamin A (5000 IU of vitamin A for 4 successive days) and single dose of ethotrexate (20mg/kg dose). Samples were collected at 24 hours after last methotrexate exposure in to 5% bovine albumin. Smears were obtained and stained with May-Grunwald and Giemsa. Thousand polychromatic erythrocytes were counted per animal for the presence of micronuclei and PCE% was also calculated. The percentage of micronuclei increased with increase in the dose of methotrexate (percentage of PCE decreased with increase in the dose of methotrexate). Combination of methotrexate and vitamin A therapy showed a significant decrease in micronuclei percentage and an increase in PCE% compared to rats treated with methotrexate alone. Hence the results of this study suggest that vitamin A protects against methotrexate induced genetic damage.