Increase in neuronal Jun immunoreactivity and epidermal NGF levels following UV exposure of rat skin

Effects of cutaneous ultraviolet (UV) irradiation on superficial nerve fibres are controversial. In the present study we demonstrate by electron microscopy that single high-dose UV exposure of rat skin results in membrane damage in peripheral nerves. Furthermore, a UV-induced accumulation of nerve growth factor (NGF) within the irradiated epidermis and a delayed increase in nuclear Jun immunoreactivity in dorsal root ganglion neurones were detected by immunohistochemistry. Our results suggest that UV-mediated alterations of axonal membranes leads to an activation of Jun transcription factor within affected neurones despite an increase in neurotrophic NGF within their innervation area.