Co-administration of Magnesium Ion Prevents Indomethacin-Induced Intestinal Ulcerogenic Lesions in Adjuvant-Induced Arthritis Rats.

In a study to find ways to prevent the side effects of indomethacin (IMC), we previously reported that magnesium ion (Mg2+) can prevent the onset of IMC-induced gastric mucosa in adjuvant-induced arthritis (AA) rats, a model for rheumatoid arthritis (RA). In this study we investigated whether the co-administration of IMC and Mg2+ prevents the formation and aggravation of intestinal ulcerogenic lesions in AA rats. The single oral administration of an excessive dose of IMC (40 mg/kg) induces hemorrhagic lesions and nitric oxide (NO) production via inducible nitric oxide synthase (iNOS) in the jejunal and ileal mucosa of AA rats, and the extent of the lesions, as well as iNOS and NO levels in AA rats are higher than in normal rats. On the other hand, the co-administration of 200 mg/kg Mg2+ attenuates intestinal ulceration and the elevation in the iNOS and NO levels in AA rats. Further, hemorrhagic lesioning and enhanced iNOS and NO levels in AA rats also result from the repetitive oral administration of 3 mg/kg IMC (therapeutic dose) for 42 d (once a day), and these changes are also prevented by the co-administration of 200 mg/kg Mg2+. In conclusion, the co-administration of Mg2+ suppresses the ulcerogenic response to IMC in the jejunal and ileal mucosa of AA rats, probably by preventing the elevation of iNOS and NO levels in the region.