ABSTRACT
To study the regulating effect of Astragalus Polysaccharides ( APS) to the mice infected by Brucella suis S2.Methods:120 BALB/c mice were randomly divided into 4 groups:experimental mice were injected APS 1 ml ( 0.4,1.2,3 mg/ml) via peritoneal cavity respectively once a day and the control group was injected with the same volume of saline for 3 days,then infected with Brucella suis S2 1 ml (1×107 L-1 ) by ip.Five mice of each group were killed through eye bloodletting at 1,6,12,24,48, 72 h respectively post-infection with Brucella suis S 2 and the peritoneal macrophage were obtained respectively to make smear.Phagocytic rate and phagocytic index were calculated by the Wright Giemsa staining after infected 1 h.TNF-α,IL-12 and IFN-γlevels of serum at different time points were measured by ELISA.The bacterial load of MΦand spleen were measured by coating method.Results:The phagocytic rate and phagocytic index of MΦin APS 3 dose groups were higher than those of the control group ( P<0.05 ).The microbial load of MΦin APS 3 dose groups at 1 h infected by Brucella suis S 2 were significantly higher than those of control,but significantly lower than those of control at 6,12,24,48,72 h after infected by Brucella suis S2.The microbial load of spleen in APS 3 dose groups at 6 h infected by Brucella suis S 2 were significantly higher than those of control ,but significantly lower than those of control at 12,24,48,72h after infected by Brucella suis S2.The concentrations of TNF-α,IL-12 and IFN-γin the serum of APS groups had significantly been improved ( P<0.05 ).Conclusion: APS can promote the activation of MΦin vivo and strengthen the activity of phagocytosis and killing to Brucella suis S 2.APS can promote the secretion of TNF-α,IL-12 and IFN-γof mice,strengthen the cellular immune response of mice to Brucella suis S 2.