Objective: In previous studies, we evaluated antibacterial activity of CM11 peptide against
multiple drug resistant clinical isolates of six bacteria species, alone and in combination with conventional
antibiotics. Although antimicrobial peptides like CM11 peptide are one of the best new alternative
antibiotics, the side effects such as toxicity are major problem. Previously the in vitro cytotoxic effects
of the peptide, viability of some cell lines have been investigated.
Methods: For in vivo studies, the present study is conducted to obtain more clarification about the toxicity
and histopathological effects of peptide in mice. For this purpose three groups of mice were treated
with different concentrations (0.2, 2.5, and 7.5 mg/kg) of peptide and then histological study for the liver,
kidney and jejunum and aspartate and alanine aminotransferase activities and total serum bilirubin
and albuminin blood plasma levels were measured.
Results: Our study showed that the activities of aminotransferase, also total serum bilirubin and albumin
levels were not significantly increased while different histological changes were observed in organs’
tissue. These changes were dependent on peptide concentration so that an increase in focal inflammation
was observed with increasing peptide concentration; however these histological changes are
not considerable in lower concentration.
Conclusion: Our findings showed that although in comparison with the control group, markers level is
normal but damages were visible in the tissues, as increase in the level of tissue damages has not led to
increased levels of markers. It seems that the lack of correlation between tissue damage and level of liver
markers probably is related to the level of damage.