Healing of Helicobacter pylori -Induced Gastric Ulcers in Mongolian Gerbils (Combined Treatment with Omeprazole and Clarithromycin)

Helicobacter pylori can colonize the stomachs ofMongolian gerbils and subsequently induce penetratingulcers five months later. Using this gerbil model, theeffects of both combined treatment with omeprazole and clarithromycin, as well as treatment witheach drug separately, on the healing of H.pylori-induced gastric ulcers, and the effects of thecessation of the drug treatment on healed ulcers wereexamined. Beginning five months after H. pylori(NCTC11637) inoculation, omeprazole (four weeks),clarithromycin (two weeks), their combination, or thevehicle was orally administered once daily. These drugs,in combination or separately, markedly enhancedulcer healing and lowered the increased myeloperoxidase(MPO) activity. While omeprazole had no effect on viableH. pylori, clarithromycin and the drug combination significantly reduced viable H. pylori. Thedegree of bacterial eradication was much higher in thecase of the drug combination compared to clarithromycinalone. Four months after cessation of the treatment, visible ulcers, hypertrophic gastritis andincreased MPO activity were found in the control animals(all H. pylori-positive). Nonetheless, only one of theeight gerbils subjected to the drug combination developed a small ulcer, although nohypertrophic gastritis was exhibited. It is concludedthat: (1) the gerbil model of H. pylori infection isuseful for the study of ulcer healing; (2) combinedtreatment with omeprazole and clarithromycin enhances theulcer healing in infected gerbils; and (3) healed ulcersdo not relapse, despite cessation of the drugtreatment.