Protective effect of prostaglandin ei on radiation-induced proliferative inhibition and apoptosis in keratinocytes and healing of radiation-induced skin injury in rats

Abstract

We examined the effects of prostaglandin Ei (PGEi) on radiation-induced proliferation inhibition and apoptosis in keratinocytes and healing of radiation-induced skin injury in a rat model. PGEi had a protective effect on radiation-induced growth inhibition in keratinocytes in vitro, but not in fibroblasts. Varying concentrations of PGEi were subcutaneously administered into the posterior neck region. X-irradiation at a dose of 20 Gy was administrated to the lower part of the back using a lead sheet with two holes 30 min to 1 h before or after the administration of PGEi. Although X-irradiation induced epilation, minor erosions, or skin ulcers in almost all rats, PGEi administration prior to irradiation reduced these irradiation injuries. Staining with terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling showed that proportions of apoptotic keratinocytes in the X-irradiated skin of PGEi-administered rats were significantly lower than for those in the skin of rats which did not receive PGEi. Cutaneous full-thickness defective wounds were then formed in X-irradiated areas to examine the time course of wound healing. Wound healing was significantly delayed because of X-irradiation, but PGEi administration prior to irradiation led to a significantly shorter delay in wound healing compared with controls. Decreasing delay in wound healing was correlated with concentration of PGEi administrated. Thus, PGEi-administration may potentially alleviate the radiation-induced skin injury.