[Prophylactic immunization of dangguibuxue decoction against Cryptosporidium infection in immune suppressed mice].

OBJECTIVE: To explore the prophylaxis of dangguibuxue decoction, a traditional Chinese medicine made from Angelica sinensis and Radix astragalus, on immunosuppressed mice infected by Cryptosporidium parvum. METHODS: 48 BALB/c mice were randomly divided into 4 groups: normal control (A), immunosuppressed control (B), high dose (C), and low dose (D). Mice in groups B, C and D were intragastrically administered with dexamethasone (DXM) for 8 days, and in the same time mice in groups C and D were given high dose (2 g/kg) and low dose (1 g/kg) dangguibuxue decoction respectively. On the ninth day all mice in groups B, C and D were orally inoculated by 1 x 10(6) oocysts of C. parvum. The amount of oocysts in feces was examined daily since being infected. 11 days after infection, the subset of T lymphocytes in peripheral blood was analyzed with flow cytometry, sIL-2R in serum and sIgA of intestinal fluid were detected by ELISA. Pathological change of duodenum and jejunum was observed microscopically. RESULTS: Compared with the immuno-suppressed control group, there were less oocysts in feces (35.0 +/- 4.21) (P < 0.01) and lighter injury in the intestinal mucosa in mice of the high dose dangguibuxue decoction group. Both the number of CD4+ T lymphocytes (47.483 +/- 4.082) and the ratio of CD4+/CD8+ (2.271 +/- 0.378) increased, sIgA [(320.19 +/- 1.94) ng/ml] in the intestinal fluid elevated and sIL-2R [(321.34 +/- 6.66) ng/ml] in peripheral blood decreased in the high dose group, with a significant difference in comparison to the immunosuppressed group (P < 0.01). All the above-mentioned indices in low dose dangguibuxue decoction group showed no significant difference with the immunosuppressed control group (P > 0.05). CONCLUSION: Administration of high dose dangguibuxue decoction plays a role of prophylaxis on the infection of C. parvum in immunosuppressed mice through improving the immune status.