[Protective effect of anhydroicaritin against peritonitis in mice]

Objective: To investigate the effect of anhydroicaritin (AHI) against zymosan-induced peritonitis in mice.

Methods: Peritonitis was induced in mice by intraperitoneal injection of zymosan. All mice were monitored for systemic toxicity and mortality for 13 d after zymosan or saline administration. In another set of experiments, the peritoneal exudates were collected. The leukocyte numbers and the production of inflammatory cytokines (IL-6, IL-10, TNF-α, MCP-1) were determined by flow cytometry. The release of nitric oxide (NO) was measured by a Griess reagent system. The CA(2+); influx in bone marrow-derived macrophages was recorded by laser scanning confocal microscopy with Fluo4-AM loading. The expression of iNOS was determined by Western blotting.

Results: AHI (4 mg/kg) prolonged survival of peritonitis mice, inhibited massive leukocyte transmigration into the peritoneal cavity, and decreased the overproduction of NO, IL-10, TNF-α, MCP-1 and IL-6. In LPS-stimulated mouse macrophages, AHI (5 μmol/L) pretreatment significantly inhibited the elevation of intracellular CA(2+);, and markedly decreased iNOS protein expression.

Conclusion: AHI possesses significant protective effects on the zymosan-induced peritonitis mice, which might be associated with the regulation of CA(2+); influx in macrophages and iNOS expression.