The nonpsychoactive cannabis constituent cannabidiol is an oral anti-arthritic therapeutic in murine collagen-induced arthritis

Abstract

The therapeutic potential of cannabidiol (CBD), the major nonpsychoactive component of cannabis, was explored in murine collagen-induced arthritis (CIA). CIA was elicited by immunizing DBA/1 mice with type II collagen (CII) in complete Freund's adjuvant. The CII used was either bovine or murine, resulting in classical acute CIA or in chronic relapsing CIA, respectively. CBD was administered after onset of clinical symptoms, and in both models of arthritis the treatment effectively blocked progression of arthritis. CBD was equally effective when administered i.p. or orally. The dose dependency showed a bell-shaped curve, with an optimal effect at 5 mg/kg per day i.p. or 25 mg/kg per day orally. Clinical improvement was associated with protection of the joints against severe damage. Ex vivo, draining lymph node cells from CBD-treated mice showed a diminished CII-specific proliferation and IFN-gamma production, as well as a decreased release of tumor necrosis factor by knee synovial cells. In vitro effects of CBD included a dose-dependent suppression of lymphocyte proliferation, both mitogen-stimulated and antigen-specific, and the blockade of the Zymosan-triggered reactive oxygen burst by peritoneal granulocytes. It also was found that CBD administration was capable of blocking the lipopolysaccharide-induced rise in serum tumor necrosis factor in C57/BL mice. Taken together, these data show that CBD, through its combined immunosuppressive and anti-inflammatory actions, has a potent anti-arthritic effect in CIA.

Figures

Figure 1

From the first clinical signs of arthritis, mice were treated daily with CBD, i.p. at the following doses: 20 mg/kg (■), 10 mg/kg (▵), 5 mg/kg (▴), or 2.5 mg/kg (○). Mice treated with the vehicle alone served as controls (□). Each point is the mean of n mice ± SEM. (A) Shown is the clinical score over 10 days of classical CIA in three pooled experiments (controls, n = 23; CBD 20 mg/kg, n = 17; CBD 10 mg/kg, n = 15; CBD 5 mg/kg, n = 15; CBD 2.5 mg/kg, n = 9). * denotes a P value < 0.05 (Mann–Whitney U test). (B) An experiment in chronic relapsing homologous CIA, where control, n = 6; CBD 10 mg/kg, n = 6, and CBD 5 mg/kg, n = 6. The area under the curve was 38.4 for the control group, 37.3 for the 10 mg/kg group, and 28.9 for the 5 mg/kg group (not significant).

Figure 2

From the first clinical signs of arthritis, mice were given CBD by oral gavage, at the following doses: 50 mg/kg (▵), 25 mg/kg (▴), or 10 mg/kg (○). Mice treated with olive oil served as controls (□). Each point is the mean of n mice ± SEM. (A) Shown is the clinical score over 10 days of classical CIA (controls, n = 6; CBD 50 mg/kg, n = 6; CBD 25 mg/kg, n = 6; CBD 10 mg/kg, n = 6). * denotes a P value < 0.05 (Mann–Whitney U test). (B) An experiment in chronic relapsing homologous CIA, where control, n = 6 and CBD 25 mg/kg, n = 6. The area under the curve was 72.3 for the control group and 49.7 for the CBD-treated group (P < 0.05, Mann–Whitney U).

Figure 3

Synovial cells were isolated from arthritic mice at day 10 of arthritis, either from control mice or mice treated with CBD, 5 mg/kg i.p. A control group of nonimmunized age-matched mice was included. Total cell number per synovial membrane was on average 50% reduced in the CBD-treated mice compared with the arthritic controls. Cultures were standardized for cell numbers. Supernatants were assessed at 24 h for bioactive TNF by the Walter and Eliza Hall Institute assay. Each dot is the mean of triplicate cultures from one individual mouse, the dots marked with * are a pool of three mice. Thus in total 10 mice per treatment group were tested. Five healthy mice were tested. The horizontal bar is the median.

Figure 4

(A) The effect of CBD on Con A-induced proliferation of splenic lymphocytes. (B) The effect of CBD on CII-specific proliferation of LNCs from arthritic mice. CBD was added in vitro at the concentrations shown for 72 h (□). For the control cultures, the vehicle (ethanol) was used at corresponding dilutions (○). Each point represents the mean ± SD of triplicate cultures. A is a representative experiment of five experiments and B of three experiments.