Lactobacillus GG bacteria ameliorate arthritis in Lewis rats.

Probiotic bacteria have beneficial effects in infectious and inflammatory diseases, principally in bowel disorders. In the case of chronic progressive autoimmune arthritides, a major goal of treatment is to reduce inflammation. We hypothesized that probiotic bacteria would ameliorate inflammation found in arthritis models. To assess this effect, Lewis rats were injected with 50 microg bovine alpha-tropomyosin (TRM) or complete Freund's adjuvant (CFA) to induce tropomyosin arthritis (TA) or adjuvant arthritis (AA), respectively. In both models, the rats were divided into 6 groups and fed 0.5 mL/d of the following suspensions: 1) heat-killed Lactobacillus GG (LGG) bacteria; 2) live LGG, both 10(11) colony-forming units (cfu)/L; 3) sterilized milk; 4) plain yogurt; 5) yogurt containing 10(11) cfu/L LGG; or 6) sterilized water. In the disease-prevention experiments, feeding started 1 wk before or after disease induction. In the therapeutic experiments, feeding was initiated at the onset of clinical arthritis. In all experiments, there were significant interactions between time and treatment (P < 0.001), except for milk, which had no effect in the therapeutic experiment. Histologically, rats fed yogurt containing LGG had a milder inflammation in all experiments (P < 0.05), whereas rats fed plain yogurt exhibited a moderate inflammatory score only in the prevention experiments. Anti-TRM antibody titers were not affected by any of the treatments in any of the experiments. Ingestion of live or heat-killed human LGG had a clinically beneficial effect on experimental arthritis. Our observation of the remarkable preventive and curative effect on arthritis using commercial yogurts containing lactobacilli, especially LGG, suggests the need for investigation of these agents in arthritic patients.