J. Xu1, J. Hu1, C. Zgheib1, M. Hodges1, K. W. Liechty1 1Laboratory For Fetal And Regenerative Biology, Children’s Hospital Colorado And The University Of Colorado Anschutz Medical Campus,Department Of Surgery,Aurora, CO, USA
Introduction: Macrophages play an essential role during wound healing and have the ability to dynamically transition between M1 and M2 phenotypes in response to signals from the surrounding microenvironment. Reactive oxygen species (ROS), including hydrogen peroxide, are one of many stimuli that have the potential to polarize macrophages. However, the role of hydrogen peroxide in macrophage polarization remains poorly defined. We hypothesize that treatment of macrophages with hydrogen peroxide will polarize the macrophage into M1 phenotype with induction of M1 gene expression and reduction of M2 gene expression.
Methods: To test our hypothesis, Raw cells from the murine macrophage cell line RAW264.7 were treated with 0, 10 uM and 100 uM hydrogen peroxide for 1 hour. Additional macrophages were treated with100 uM hydrogen peroxide for 5, 20, or 60 minutes. M1 and M2 gene expression was analyzed using real-time PCR.
Results: Macrophages treated with hydrogen peroxide showed significantly increased gene expression of the M1 macrophage markers (iNOS, and IL1-beta), while demonstrating decreased gene expression of M2 macrophage markers (CD206) in a dose and time dependent manner.
Conclusion: These findings provide evidence that hydrogen peroxide can polarize macrophages to the M1 phenotype. Furthermore, our results demonstrate that increased reactive oxygen species can perpetuate chronic inflammation through persistent M1 macrophage polarization and decreased M2 macrophage polarization. The use of anti-ROS therapies may help to create a microenvironment that decreases M1 polarization and promote M2 polarization and resolution of the inflammatory response.