Histochemical and biochemical modifications induced by experimental irradiation of human skin maintained in survival conditions and modulation by application of an emulsion containing trolamine.

Abstract

Radiotherapy continues to cause skin disorders. In this article, with the aid of our human skin model maintained in ex vivo survival conditions for 15 days, we describe the modifications caused by irradiation and their modulation by a trolamine-containing emulsion (Biafine). Normal human skin fragments were maintained in organ culture. One ionizing radiation session with 5 Gy was applied. Skin parameters were evaluated 24 h after the radiation session and were compared with a nonirradiated skin fragment: vascular modifications (histology), edema, epithelial proliferation, interleukin (IL)-1alpha and IL-6. Another series of skin fragments was maintained in survival conditions for 15 days after the radiation session to evaluate collagen neosynthesis by fibroblasts and any vascular changes (CD34). After irradiation the basal cell proliferation was reduced by approximately 50%. Extensive vasodilation occurred with altered capillary permeability accompanied by decreased CD34 transmembrane protein expression. Collagen synthesis and IL-1 secretion were increased. Biafine significantly reduced capillary alterations, restored CD34 expression as well as epithelial cell proliferation and significantly decreased collagen synthesis and IL-1 expression. With this ex vivo human skin model we confirmed the main modifications induced by radiotherapy as previously described in animal models: decreased basal cell proliferation and endothelial cell alterations and increased collagen synthesis by fibroblasts, probably under the influence of IL-1. The effect of Biafine emulsion on these histological and biochemical parameters may support its clinical efficacy.