Effect of Momordica charantia polysaccharide on immunomodulatory activity in mice

Momordica charantia polysaccharides (MCPs) have been reported to exert beneficial roles, such as disease healing, in medicine and pharmacy. However, little is known about their effects on immunomodulation. The present study aimed to explore the possible effects of Momordica charantia polysaccharide (MCP) on the immunomodulatory activity of mice lymphocytes. To this aim, male BALB/c mice aged 6-8 weeks were assigned to the following six experimental groups: i) Normal (NG); ii) model (MG); iii) positive (PG); iv) MCP low-dose (MLG); v) MCP medium-dose (MMG); and vi) MCP high-dose (MHG). An immunosuppressive model was established by the intraperitoneal injection of cyclophosphamide in all groups apart from NG. The NG and MG mice were fed with distilled water, whereas the PG mice were administered with levamisole and the MLG, MMG and MHG mice were fed on low, medium and high (100, 200 and 300 mg/kg, respectively) doses of MCP for 21 consecutive days. Subsequently, the mice underwent surgical procedure and were analysed using a range of procedures, including measurement of the thymus index (TI) and spleen index (SI), assessment of the lymphocyte proliferation rate and cell phagocytosis of peritoneal macrophages, lymphocyte proliferation, secretion and mRNA expression of cytokines IFN-γ, IL-6 and IL-12. The mice divided into six groups as mentioned above and treated for 7 days, in the first 6 days, except NG group, mice in each group were desiccated in the abdominal cavity and sensitized by 1% dinitrofluorobenzene (DNFB). On day 6, mice were sensitized with 20 µl DNFB/acetone/olive oil solution behind the right ear and in front of the right ear. Compared with those in the NG mice (not injected with 80 mg/kg cyclophosphamide), the TIs and SIs of the PG, MLG, MMG and MHG mice were increased. In addition, the inhibitory rate of ear swelling and the phagocytic activity of peritoneal macrophages in the PG, MLG, MMG and MHG mice were increased compared with those of MG. Furthermore, the lymphocyte proliferation rate, the secretion and relative mRNA expression levels of cytokines IFN-γ, IL-6 and IL-12 were significantly increased in the PG, MMG and MHG mice compared with those in the NG mice. The results from the present study suggest that treatment with MCP led to an upregulation of the organ indices of immunosuppressed mice, reduced their delayed allergic reaction indicated by the differential cytokine levels, improved the phagocytic activity of peritoneal macrophages, enhanced the proliferation rate of lymphocytes, increased the secretion and expression of IFN-γ, IL-6 and IL-12. Therefore, MCP may improve the immune function of the immunosuppressed mice.