141 Potential Use of Nitric Oxide Gas as an Antimicrobial Agent in Cutaneous Wound Infection

Abstract

Despite recent advances in wound care, chronic infected ulcers still remain a huge challenge to the modern society. Nitric oxide has been identified as a mediator for important biological processes such as vasodilation, antimicrobial, and wound repair. The aim of the present study was to explore the antimicrobial properties of exogenous nitric oxide gas (gNO) as well as its effect on skin cells in vitro. To test this, a specialized gNO chamber was designed to expose S. aureus and P. aeruginosa in saline continuously to 200 ppm gNO or air. A colony count was obtained following gNO treatment. Furthermore, fibroblast-populated collagen gel, keratinocytes, and endothelial cells were cultured in DMEM, KSFM, and M199, respectively. Endothelial migration was tested by a 3D Matrigel tubule formation assay. Fibroblast matrix production and keratinocyte differentiation were monitored by mRNA expression of procollagen type I, interstitial collagenase, and involucrin. All cells were exposed to 200 ppm gNO for 8 hours a day for 3 consecutive days. A MTT assay was used to observe cell proliferation. The results revealed 100% bacterial kill following 4 hour exposure to 200 ppm gNO. Interestingly this dose did not exhibit any significant toxic effect on fibroblast, keratinocyte, and endothelial proliferation. Dermal fibroblasts migration out of the collagen gel was not affected by gNO treatment when compared to the control. The keratinocytes in both groups were able to express involucrin, an indicator of cell’s ability to differentiate. The migration and tube formation by endothelial cells within the matrigel was not compromised following gNO treatment. In conclusion, the present study provided evidence for potential application of gNO for reducing bacterial burden in chronic infected wounds without compromising re-epithilialization, proliferation, and angiogenesis in the wound healing process. Acknowledgment: This study was funded by PulmoNOx Medical Inc.