Background Montanine is an alkaloid isolated from Rhodophiala bifida, a plant used in folk medicine (1) and never before tested in inflammatory diseases.
Objectives To evaluate the effect of montanine as an in vivo anti-inflammatory therapy in Antigen-induced Arthritis (AIA) and Collagen-induced Arthritis (CIA) models, and to characterize its effects on immune and hematologic phenotypes in vivo and in vitro, including fibroblast-like synoviocytes (FLS) invasiveness.
Methods AIA was induced in 24 Male BALB/c mice with methylated bovine serum albumin (mBSA) and mice divided into 4 groups: vehicle (saline) or montanine at 0.3, 1 or 3mg/kg, intraperitoneal twice a day. Treatment started one day before intra-articular injection of mBSA. Paw nociception at 0, 3, 5 and 24 hours and leukocytes migration into the knee joint at 24 hours were evaluated. DBA/1J mice were induced with CIA and divided into a preventive (n=24; 16 days of treatment at doses 0.05; 0.25 and 0.5 mg/kg) or therapeutic group (n=23; 10 days of treatment at doses 0.5 and 1.5 mg/kg starting after the onset of arthritis). BALB/c controls (n=36) were treated for 14 days at doses 0.05, 0.5 and 1.5 mg/kg and hematology, cytokine and leukocyte subpopulation and histophatology of lymphoid organs were evaluated. Montanine 1mM was used for lymphocyte proliferation assay with ConA (n=7). FLS invasion over 24 hours was assayed in a transwell Matrigel-coated chamber in the presence or absence of Montanine 1mM (n=5). Statistical analysis: ANOVA or t-test.
Results In AIA Montanine decreased leukocyte articular migration (figure 1A) in a dose-dependent manner by as much as 90% (3mg/kg: 4.15±1.46x104 leukocytes/cavity) compared with vehicle (43.5±9.73x104 leukocytes/cavity) (p<0.001) and reduced nociception in all doses at 5 and 24h (p<0.01), compared with vehicle. In the CIA preventive treatment (figure 1B), montanine 0.25 and 0.5 mg/kg reduced articular score that could be detected as early as day 8 and persisted throughout the observation period (p<0.05). Montanine 0.5mg/kg also significantly reduced CIA joint severity score by as much as 39,52% compared to vehicle in the therapeutic arm (figure 1C), an effect that was noticed as early as day 3 and persisted throughout the observation period (p<0.01), with reduced histology damage (p<0.03). Nociception was significantly reduced at days 2 and 10 (p<0.05) compared with vehicle. Montanine inhibited lymphocyte proliferation stimulated with ConA by 54.78% (p<0.01). Montanine 1mM decreased FLS invasion by 54% (p=0.031) (figure 1D). Montanine did not have any significant effect on the hematologic and immunological parameters analyzed in BLAB/c controls.
Conclusions Montanine significantly improved experimental arthritis, reduced joint damage and nociception in both acute and chronic models. Moreover, montanine reduced lymphocyte proliferation and FLS invasion, two processes implicated in RA pathogenesis and did not have any obvious toxicity. These results suggest that montanine has the potential to become a new class of drugs to treat inflammatory and autoimmune diseases such as arthritis.
Louw CAM et al. J. Ethnopharmacol. 2002:82: 147-154.
Acknowledgements FIPE-HCPA, CAPES, CNPq
Disclosure of Interest None declared