Background Beta-glucans are naturally occurring polysaccharides, which are integral constituents of the cell wall of bacteria, plants and yeasts. They modify biological response, have anticarcinogenic activity and enhance non-specifically the host immune system by activating the complement system, enhancing the function of macrophages, leukocytes and natural killer cells. Their antioxidant, analgesic and anti-inflammatory effects are suggested as well.
Objectives The aim of this study was to evaluate the effect of prophylactic and therapeutic dose of β-(1,3/1,6)-D-glucan isolated from mushroom Pleurotus ostreatus (β-glucan-PO) on the methotrexate (MTX) treatment of adjuvant arthritis (AA) in rats.
Methods Rats with AA were treated with methotrexate (1 mg/kg/week), β-glucan-PO in a prophylactic dose (1 mg/kg every second day) or their combination for a period of 28 days from adjuvant application. In a second test, MTX (1 mg/kg/week) and β-glucan-PO in a therapeutic dose (15 mg/kg every day) were applied from day 13 to day 35 after immunization. Body mass, hind paw swelling, arthrogram scores, and the level of serum albumin were measured as markers of inflammation and arthritis.
Results Preventive treatment with a low dose of MTX significantly inhibited the markers of both inflammation and arthritis. MTX and its combination with β-glucan-PO significantly (p<0.001) increased the body mass of arthritic rats. β-glucan-PO administered alone had no effect on body mass but significantly decreased both the hind paw swelling and arthritic score (p<0.05). In combination with MTX, β-glucan-PO markedly potentiated the beneficial effects of MTX alone (p<0.01), which resulted in a more significant (p<0.001) reduction of hind paw swelling and arthritic scores. The concentration of albumin in the serum of arthritic controls was significantly lower than in the healthy controls. Both MTX alone (p<0.01) and the combination treatment with MTX + β-glucan-PO (p<0.001) significantly inhibited the decrease of serum albumin. Therapeutically, MTX had no significant effect on the markers of inflammation and arthritis. β-glucan-PO alone in a high dose (15mg/kg body mass) inhibited hind paw swelling, arthrogram scores, and the decrease of serum albumin (p<0.01), however only 8 days after beginning of the treatment.
Conclusions Prophylactic and therapeutic administration of β-glucan-PO alone significantly reduced both the hind paw swelling and arthrogram scores. In addition, β-glucan-PO increased the efficacy of basal treatment with MTX in rats with adjuvant arthritis. In patients with rheumatoid arthritis this immunomodulator may prevent the secondary infections and restore impaired immunological homeostasis.
Disclosure of Interest None declared