<b>The Effect of <i>Lactobacillus rhamnosus</i> and <i>Lactobacillus delbrueckii</i> on Fibroblast-like Synoviocytes (FLS) Isolated from the Synovium of Rheumatoid Arthritis Patients</b>

Background: Rheumatoid arthritis (RA) is an autoimmune and inflammatory disorder and the most common type of autoimmune arthritis that causes joint inflammation and synovial membrane hypertrophy. Synovium of RA patients contains fibroblast-like synoviocytes (FLS) which contribute to cartilage degradation and inflammation through producing inflammatory cytokines. Recent researches have reported that probiotics can induce immunomodulatory activity in inflammatory disorders. Therefore, this study was conducted to investigate the effects of Lactobacillus rhamnosus and Lactobacillus delbrueckii on the FLS of RA patients. Methods: The therapeutic effects of probiotic strains on FLS and their related molecules in RA patients were evaluated. FLS of patients with RA were cocultured for 48 h with Lactobacillus rhamnosus, Lactobacillus delbrueckii and a mixture of both probiotics. The supernatants of FLS cultured with probiotics were collected for quantification of IL-6 and TNF-α cytokines by ELISA. The mRNA expression of IL-6, TNF-α, MMP3 and RelA was examined in FLS derived from RA patients by Real Time-PCR. Results: Live Lactobacillus rhamnosus and Lactobacillus delbrueckii, alone and in combination, significantly increased the expression of IL-6, TNF-α, MMP3 and RelA in FLS cells (p&lt;0.05). However, a considerable difference was not observed among the groups that were treated with these two strains of Lactobacillus. Conclusion: The current research may indicate these probiotics do not alleviate the inflammatory response of FLS cells in RA patients. Further investigation is needed to evaluate the probiotic effects of these bacteria on RA.