Singlet oxygen is an early intermediate in cytokine-dependent ultraviolet-A induction of interstitial collagenase in human dermal fibroblasts in vitro.

Ultraviolet (UV) A irradiation of human dermal fibroblasts elicits an increase in specific mRNA amounts and bioactivities of the cytokines IL-1alpha, IL-1beta, and IL-6. These effects are enhanced in deuterium oxide-based medium and are diminished in the presence of non-toxic concentrations of sodium azide. Furthermore, generating singlet oxygen outside the cells by irradiation of rose bengal-coated resin particles with visible light (lambda > 450 nm) results in the induction of interstitial collagenase, IL-1 and IL-6, similar to the response observed with UVA irradiation. These observations suggest that singlet oxygen is an early intermediate in the signaling pathway of IL-1 and IL-6 mediating UVA induction of interstitial collagenase (E.C. 3.4.24.7). Furthermore, singlet oxygen appears to initiate this complex UV response at the cell membrane.