BMAL1 and osteoarthritis: In addition, there is significantly increased expression of a both circadian and complement genes, such as Dbp, Per2, Npas2 (homologto Clock), Arntl (BMAL1), and the proven osteoarthritis markers, C1q, C3, and C5aR1, found in the joint tissues obtained from experimental temporomandibular joint-osteoarthritis (TMJ-OA) rat models (He et al., 2018).