Effects of polysaccharide fractions isolated from Caltha palustris L. on the activity of phagocytic cells & humoral immune response in mice with collagen-induced arthritis: A comparison with methotrexate.

BACKGROUND & OBJECTIVES: The extracts from Caltha palustris L. have been shown to be beneficial for treating arthritis and rheumatism. In this study, the immunomodulatory effects of polysaccharide fractions B and C of C. palustris extracts were studied, using the collagen-induced arthritis (CIA) mouse arthritis experimental model. The aim was to determine the activity of blood phagocytic cells and humoral immune response in CIA mice treated with polysaccharide fractions from C. palustris. METHODS: The effects of fractions B and C of C. palustris were explored by evaluating phagocytic activity of peripheral blood granulocytes and monocytes and humoral immune response in sheep red blood cell (SRBC)-immunized mice. The results were compared with methotrexate (MTX) treatment. Following the onset of CIA, DBA/1J mice were treated for 21 days with B or C fractions (10 mg/kg; i.p.) or MTX (every 48 h, 6.6 mg/kg; i.p.). RESULTS: The results showed that fraction B reduced the level of interleukin (IL)-1ß, boosted nitric oxide synthesis in murine peritoneal macrophages stimulated in vitro with lipopolysaccharide and enhanced the monocyte phagocytic activity. Exposure of SRBC-immunized mice to fraction B and MTX during the course of CIA resulted in decreased total anti-SRBC haemagglutinin titres. INTERPRETATION & CONCLUSIONS: Fraction B of C. palustris polysaccharides modulated macrophage function and exerted beneficial effects on the clinical course of CIA in mice. The results also suggested efficacy of fraction B was comparable to that of MTX treatment for certain parameters.

The effects of bestatin on humoral response to sheep erythrocytes in non-treated and cyclophosphamide-immunocompromised mice.

The effects of bestatin on humoral immune response to sheep erythrocytes (SRBC) and restoration of the response impaired by a single cyclophosphamide dose (350 mg/kg) were tested on mice. Bestatin (at doses of 10, 1, and 0.1 mg/kg) was administered intraperitoneally (i.p.) 5 or 10 times. The pharmacological immunosuppression was induced by a single i.p. injection of cyclophosphamide (350 mg/kg) administered 24 h before the first bestatin dose. The mice were immunized i.p. with SRBC 24 h after the last dose of bestatin. It was found that multiple administration of bestatin at all three doses potentiated the humoral response to SRBC in non-treated mice, resulting in an increased number of plaque-forming cells (PFC) and 2-mercaptoethanol (2-ME)-resistant anti-SRBC antibodies. However, five times administration of bestatin at the doses under investigation caused further decreases in total anti-SRBC hemagglutinins. A single injection of cyclophosphamide (350 mg/kg) suppressed humoral response of mice to the antigen. Administration of bestatin after pharmacological immunosuppression partially prevented the suppressive action of cyclophosphamide in the in vivo model of the humoral immune response to SRBC. The protective action of bestatin was both dose- and schedule-dependent. Ten times' exposure to a bestatin dose of 0.1 mg/kg after a high cyclophosphamide dose partially reduced the suppressive effect of this drug on humoral response of SRBC-immunized mice, increasing PFC on days 4 and 7 after immunization, which coincided with restored ability of the lymphocytes to produce the 2-ME-resistant hemagglutinins on day 7 and the total anti-SRBC hemagglutinins on day 14 after priming.

Influence of polysaccharide fractions isolated from Caltha palustris L. on the cellular immune response in collagen-induced arthritis (CIA) in mice. A comparison with methotrexate.

ETHNOPHARMACOLOGICAL RELEVANCE: The extracts from Caltha palustris have been used in traditional Canadian and Asian medicine to treat arthritis and rheumatism. AIMS: The aim of the study was to investigate the anti-arthritis and immunomodulatory activity of the polysaccharide fractions B and C of Caltha palustris L. herbal extracts in collagen-induced arthritis (CIA) mice, an animal model of rheumathoid arthritis. The results were compared with those of methotrexate (MTX) treatment. MATERIALS AND METHODS: CIA was induced in male and female DBA/1J mice by intradermal injection of chicken type II collagen in Freund's complete adjuvant (cFA). Booster injection of collagen (in incomplete Freund's adjuvant) was given on day 21 of the experiment. Mice were treated daily for 21 consecutive days with investigated fractions B or C at a dose of 10mg/kg (the first dose was given 24h after the booster) or phosphate buffered saline (PBS) (negative and positive control group). MTX was administered in parallel, intraperitoneally at three weekly cycles-every 48 h for 3 weeks at a dose of 6.6 mg/kg, the first dose was given on day 22 of the experiment. The severity of arthritis was evaluated by arthritic scores. Flow cytometry was used to investigate subsets of T lymphocytes in the thymus, and T and B lymphocytes in the spleen, and in mesenteric lymph nodes. T regulatory lymphocytes in the spleen were also quantified by means of flow cytometry. The levels of IL-2, IL-6, IL-10, IFN-γ and TNF-α in serum were also measured. RESULTS: The results revealed that fraction B significantly reduced the severity of joint swelling and erythema to a similar degree as MTX. It was also found that B fraction and MTX inhibited leucocytosis in peripheral blood caused by CIA, however the inhibitory effect of MTX persisted longer than that of fraction B. The analysis of lymphocyte T subsets demonstrated that both investigated fractions and MTX caused a partial or complete normalization in the percentage and the absolute number of CD4(-)CD8(-) thymocytes (immature, double-negative cells), and increased the percentage of CD8(+) T cells in peripheral lymphoid organs of mice with CIA. Moreover, an increase in the percentage of CD4(+) thymic cells was observed after treatment with fraction B or MTX. Fraction C showed the weakest effect in normalization of the percentage and the absolute number of CD4(-)CD8(-) thymus lymphocytes in mice with CIA. The potency of fraction B was comparable to MTX. A significant decrease in the percentage and the absolute count of splenic T-regulatory cells (CD4(+)CD25(+)FOXP3(+)) was observed after treatment with both Caltha palustris fractions. The inhibiting influence of investigated fractions on TNF-α serum concentration was significant and lasted longer in the case of fraction C. Production of other cytokines was modulated slightly (increase in IFN-γ) or markedly (decrease in IL-2). CONCLUSION: The results of the experiment suggested that the administration of polysaccharide B fraction from Caltha palustris extract significantly suppressed the progression of CIA. These results are similar to those obtained in the case of MTX treatment. This indicates that fraction B may be a potent candidate for botanical anti-arthritic agent.