BMAL1 and rheumatoid arthritis: Experiment has shown that the expression of BMAL1 mRNA in LPS induced arthritis mice was lower than that in control group, and it pointed out that BMAL1 play an vital role in anti-inflammation when monocytes and macrophages were attacked by immune stimulants.[21] Another study discovered that after serum shock, the expression level of BMAL1 mRNA in RA synovial fibroblasts was much lower than that in OA control group, and the peak expression was delayed.[22]