Complete Freund's adjuvant promotes the increases of IFN-gamma and nitric oxide in suppressing chronic arthritis induced by pristane

The aim of this study was to determine therapeutic effects of complete Freund's adjuvant (CFA) on the progression and relapsing of pristine-induced arthritis (PIA) and investigate the mechanism involved. Chronic relapsing arthritis was induced by pristine in LEW rats. After onset of arthritis, rats were intradermally injected CFA and rats in control group were injected the same volume of PBS. Arthritis was monitored visually, and joint pathology was examined histologically. Cytokine mRNA expression in inguinal lymph nodes was assessed by RT-PCR. The levels of nitric oxide (NO) in serum were measured by colorimetric assay. The results showed that CFA significantly suppressed the progression and relapsing of PIA. Relapsing rate of PIA in CFA-treated group was 12.5% and it was 85.7% in PBS-control group (P < 0.005). CFA markedly inhibited the infiltration of inflammatory cells and cartilage damage in the joints of CFA-treated rats and promoted the increases of IFN-y mRNA and NO levels. The present study provided an implication that adjuvant therapy may be a new strategy for the treatments of rheumatoid arthritis (RA) and other chronic inflammatory diseases.