Objective: To study the effect of secreting type antibacterial peptides from Musca domestica Larvae in mice with abdominal infection. Method: Thirty-two BALB/c mice were selected and divided randomly into four groups. Experiment group 1(prophylactic intervention of antibacterial peptide): 10 mg·kg-1·d-1 antibacterial peptide was administered prophylactic before bacterial infection for 3 days. Experiment group 2 (remedial intervention of antibacterial peptide): 10 mg·kg-1 antibacterial peptide was administered after bacterial infection. Model group: normal sodium was administered after bacterial infection. Normal mice were control. The number of bacteria in ascitic fluid was examined in 4 h and 12 h after bacterial administration. These contents were measured of plasma Tumor nercosis factor-alpha(TNF-α)

interleukin-6(IL-6)

nitric oxide(NO) and endotoxin in 4

8

12 h

and 24 h after bacterial infection. Result: There was a distinct content decrease of plasma TNF-α

IL-6

NO and endotoxin in antibacterial peptide pretreatment group compared with those in model group. In remedial intervention group

bacterial number in ascitic fluid and endotoxin content in peripheral blood were obviously lower than those in model group

while changes of other indexes were not as obvious as those in pretreatment group. Conclusion: The secreting type antibacterial peptides from M. domestica could show the immunoregulation in bacterial infection mice.