Effects of Myeloperoxidase on Methicillin-Resistant Staphylococcus aureus-Colonized Burn Wounds in Rats

Abstract

To achieve better therapeutic results in burn wound infections and to examine alternatives to antibiotics, we designed this study to elaborate the role of myeloperoxidase (MPO) on infected burn wounds in rats. Approach: We compared chemical properties as well as bacteriostatic ability of MPO in different concentrations with NeutroPhase. Subsequently, we applied MPO (MPO group), NeutroPhase (NeutroPhase group), NaCl+H 2 O 2 (NaCl+H 2 O 2 group), or NaCl (control group) on rat dorsal burn wounds inoculated with methicillin-resistant Staphylococcus aureus (MRSA). Their effects on MRSA-colonized wounds were evaluated by microscopy, histologic section, and Western blot. Results: MPO produced more H + and HClO-, leading to a more acidic environment. Moreover, MPO inhibited the growth of MRSA more intensely after 6 h of inoculation ex vivo. In vivo the open wound rate in the MPO group was significantly lower, while the contraction rate and epithelialization rate of MPO group were higher than that of the control group, NaCl+H 2 O 2 group, and NeutroPhase group on day 20. The hematoxylin and eosin staining of MPO group showed better wound healing than other groups. More vascular endothelial growth factor (VEGF) was expressed in wound tissue of MPO group by Western blot. Innovation: This is the first study to use MPO for MRSA-colonized burn wound therapy. Conclusion: MPO displayed more effective bacteriostatic ability, possibly beneficial for MRSA-colonized wound healing.

Severity of thermal burn injury is associated with systemic neutrophil activation

“…Further studies investigated more neutrophil-specific factors. Bacteriostatic effects of topically administered MPO were demonstrated in Staphylococcus aureus -infected burn wounds 40 and increased MPO activity was observed following burn injury in rats 41 . Intriguingly, burn injury reduced NETosis, indicated by diminished CitH3 levels, via pulmonary immunosuppression 31 .…”