In mice genetically deficient for CB2, experimentally induced osteoarthritis was significantly worse than in control mice (Sophocleous et al., 2015). In addition, naturally occurring osteoarthritis was more severe in CB2 deficient mice than in controls.
This suggests that CB2 is involved in the development of (osteo-)arthritis and that CB2 activation may protect against osteoarthritis.
In mice with collagen-induced Arthritis a CBD dose of 5 mg/kg/day i.p. or 25 mg/kg/day oral effectively blocked disease progression and suppressed joint damage, lymphocyte proliferation and IFNγ and TNF expression (Malfait et al., 2000).
Malfait, A.M., Gallily, R., Sumariwalla, P.F., Malik, A.S., Andreakos, E., Mechoulam, R., and Feldmann, M. (2000). The nonpsychoactive cannabis constituent cannabidiol is an oral anti-arthritic therapeutic in murine collagen-induced Arthritis. Proc. Natl. Acad. Sci. U. S. A. 97, 9561–9566.
Sophocleous, A., Börjesson, A.E., Salter, D.M., and Ralston, S.H. (2015). The type 2 cannabinoid receptor regulates susceptibility to osteoarthritis in mice. Osteoarthr. Cartil. OARS Osteoarthr. Res. Soc.