Subacute toxicity of antimicrobial peptide S-thanatin in ICR mice

Antibiotics are commonly used for infectious diseases and saved a lot of lives since its discovery, but the emergence of drug-resistant microorganism has brought a tremendous challenge to clinical therapy at present. Antimicrobial peptides, which are of broad antimicrobial spectrum and rare resistance development in pathogens, are expected to replace conventional antibiotics. S-thanatin, a novel antimicrobial peptide with 21 amino acid residues, was proved of significant benefit on therapy of pathogens infection. To evaluate the security of S-thanatin, its subacute toxicity was examined in ICR mice by continually intravenous injection with 125, 50, 20 mg/kg (1/4, 1/10, 1/25 LD(50)) or saline with equal volume for two weeks. Results demonstrated that neither significant difference of serum chemistry and hematology, nor pathological changes were changed in major organs caused by S-thanatin between groups. In conclusion, S-thanatin appears to be a safe antimicrobial peptide for further preclinical trials.