Redox regulation of wound healing? NF-κB activation in cultured human keratinocytes upon wounding and the effect of low energy HeNe irradiation

The complex process of wound healing as well as the signaling systems orchestrating this intricate process remain incompletely defined. Using human keratinocytes in primary culture, we sought to characterize their NF-κB responses to wounding alone or in combination with other treatments. We initially characterized these cultured human keratinocytes responses to known NF-κB activators (PMA, TNF-α and IL-1) using two different assays, immunohistochemistry and electrophoretic mobility shift (EMSA). After eliciting the expected NF-κB responses, we applied these same assays to assess responses to either wounding or HeNe irradiation alone. The results obtained indicated that only a modest/sporadic activation of NF-κB was elicited by these which was only detectable using immunohistochemistry. When the combination of wounding and HeNe irradiation on NF-κB status was assessed, a marked, localized activation of NF-κB in keratinocytes along the wound edge was found. Treatment induced NF-κB activation (e.g., wounding, HeNe irradiation and combined wounding and HeNe irradiation) was abrogated by pyrrolidine dithiocarbamate (PDTC) which inhibits NF-κB activation through an as yet incompletely understood (antioxidant?) mechanism. These data therefore suggest that NF-κB and oxidation mediated changes in its activation state likely play important roles in normal cutaneous wound healing.