Treatment Effect of Antimicrobial Peptide LL-1 on E.coli Infection in Vivo

ZHOU Lingling; WANG Yuhang; SA Junmeng; MA Xiaoning; ZHANG Yuanchen; LIAN Kaiqi; CAO Jinling

doi:10.15933/j.cnki.1004-3268.2025.05.016

Abstract：The aims are to evaluate the therapeutic effect of antimicrobial peptide LL-1 on E.coli infected mice in vivo and lay a foundation for its clinical application.Firstly,the mice model of E.coli infection was established and the optimal infection dose was determined.Mice infected with E.coli were then treated with the antimicrobial peptide LL-1 and enrofloxacin.The effect of the treatment in vivo was evaluated according to the survival rate of mice,blood routine parameter,organ index,E.coli bacterial load,etc.And the histological changes of mice organs were detected to analyze the influence of antimicrobial peptide LL-1 on mice.The results showed that the optimal infection concentration for establishing a mouse model of E.coli infection was 108 cfu/mL.The survival rate of the mice in the positive control group(POS group)was 30％,while the treatment group mice with 80 mg/kg LL-1(PEPJ group)reached 100％.Compared with the POS group,the liver index of the PEPJ group was extremely significantly increased,and the spleen index was significantly decreased,and the amount of E.coli in the spleen and lung were significantly decreased;Among the main parameters of blood routine in mice,the intermediate cell count of PEPJ group was significantly reduced;HE staining showed that LL-1 significantly alleviated multi-organ(liver,spleen,kidney,lung)lesions,inflammatory cell infiltration,and intestinal villus shedding induced by E.coli infection.And the overall therapeutic effect of 80 mg/kg LL-1 on mice infected with E.coli was better than that of the treatment group with 200 mg/kg enrofloxacin.In conclusion,the antimicrobial peptide LL-1 has a good effect against E.coli in mice,which lays a foundation for further study of the role and clinical application of the antimicrobial peptide in the future.