[IL-1 beta mRNA expression in patients with rheumatoid arthritis]

Abstract

Using arthroscopy techniques, 6 synovia samples from patients with rheumatic diseases were obtained. Of these, 2 patients had rheumatoid arthritis (RA), 2 had meniscus damage (MD), 1 had osteoarthritis (OA), and 1 had osteochondritis (OC). Using the guanidinium isothiocyanate method, total RNA from synovia was extracted, and 18S and 28S sedimentation bands (rRNA) were separated by electrophoresis. Plasmid containing the 1.3kb cDNA of IL-1 beta were extracted from E. coli by alkaline lysis. Subsequent digestion with XHO1 and then separation on gel isolated the 1.3kb cDNA for use as a probe. The probe was then labeled with 32P-dATP by nicktranslation and hybridized to the synovial RNA extract. The autoradiograph showed that in 4 cases of non-RA, the IL-1 beta cDNA did not hybridize to the synovial mRNA extract. An intense hybridization band was visible for mRNA from one RA case. The clinical and laboratory parameters and X-rays of both knees and wrists of this case were all abnormal, and a rthroscopic findings showed pathological rheumatoid changes of synovium. In addition, this patient did not receive any DMARDs treatment for the RA. The other RA case did not have any hybridization bands. However, this patient did receive DMARDs treatment, and the RA went into remission. The Northern blot result above suggests that IL-1 beta mRNA expression in synovia is negative in non-RA cases and in cases where RA is in remission after DMARDs treatment. In the case with clinically active RA, IL-1 beta is highly expressed, as evidenced by the intense hybridization band.