Timecourse study of UVB-induced cytokine induction in whole mouse skin

Ever since the skin was recognized as a site of immunologic activity, a number of laboratories have studied the production of cytokines by skin cells and the effects of chemicals, allergens, contact irritants and UVB radiation on their production. Most research to date has been carried out using either purified populations of primary cells, or established cell lines. Cytokines, however, do not function in isolation but they appear in human tissues within the context of other cytokines that can, in turn, strongly influence the final biological outcome. Therefore, in vivo studies using whole skin are more physiologically relevant since all cell types are present and interactions among them are allowed to proceed. We report here the results of a detailed timecourse study using whole mouse skin, consisting of both dermis and epidermis, irradiated with either a low or high dose of UVB and analyzed using a Multi-probe RNase protection assay system. The results show that in whole skin the kinetics of cytokine induction are different than what was previously observed in tissue culture. In addition to already known skin-associated cytokines, we report here the presence and UVB induction of cytokines not previously reported.     

Interleukin 11 reduces apoptosis in UVB-irradiated mouse skin

BACKGROUND: UVB radiation, the major cause of skin cancer, causes apoptosis in the skin, characterized by the appearance of 'sunburn cells'. Interleukin 11 (IL-11) has been shown to protect cells in the gastrointestinal system from chemotherapy and radiation-induced death. OBJECTIVE: To determine whether exogenous IL-11 has any effect on the UVB-induced apoptosis of cutaneous tissues. METHODS: Mice were injected with IL-11 or vehicle control prior to irradiation, and TUNEL assays were performed on paraffin-embedded tissue sections at various times after irradiation. RESULTS: Exogenous IL-11 protects epidermal keratinocytes, epithelial cells of the hair follicles inflammatory cells and fibroblasts in the dermis from UVB-induced apoptotic death. CONCLUSION: These findings suggest that IL-11 may play a role in the general homeostasis of the skin.