Preventive effect of co-administration of water containing magnesium ion on indomethacin induced lesions of gastric mucosa in adjuvant-induced arthritis rat.

It is well known that nonsteroidal anti-inflammatory drugs (NSAIDs) have significant side effects, such as gastroenteropathy, and that rheumatoid arthritis patients taking NSAIDs are more susceptible to NSAIDs-induced gastric lesions as compared with patients with other diseases. We demonstrate the preventive effect of the co-administration of bittern water (BW, nigari-sui in Japanese), which enables the effective intake of Mg(2+), on the ulcerogenic response to indomethacin in adjuvant-induced arthritis (AA) rats. Four kinds of BW with different Mg(2+) contents; ranging from 10-200 mg/l Mg(2+) (BW-10, 25, 50, 200) were used in this study. Arthritis was induced by the injection of 50 microl of a suspension of 10 mg/ml heat-killed butyricum (Mycobacterium butyricum) in Bayol F oil into the plantar region of the right hind foot and tail of rats. Oral administration of indomethacin (40 mg/kg) caused hemorrhagic lesions in the gastric mucosa of AA rats at 14 d after adjuvant injection, and the lesion score of AA rats administered indomethacin was significantly higher than that of normal rats administered indomethacin. The expression of the mRNA for inducible nitric oxide synthase (iNOS) mRNA expression and the production of nitric oxide (NO) in the gastric mucosa of AA rats were also increased by the administration of indomethacin. The co-administration of BWs decreased the ulcerogenic response to indomethacin in AA rats. In addition, the administration of BW attenuated the increase in iNOS mRNA expression and NO production in AA rats receiving indomethacin. The oral administration of Mg(2+) to AA rats had a potent preventive effect on the ulcerogenic response to indomethacin in AA rats, probably due to an inhibition in the rise in iNOS and NO levels in the gastric mucosa.