Experimental Study On The Mechanism Of Preventing Radiateon-induced Actue Skin Ulcers Used By DMSO

Objective: To observe the function of preventing radiateon-induced actue skin ulcers used by Dimethyl Sulfoxide (DMSO) and to study the expression of several growth factors (TGF-β, PDGF, VEGF) and cell apoptosis and apoptosis-realated genes in the formation and development of acute radiation-induced skin ulcers affected by DMSO. Methods:in this study, 60 wistar rats were divided into two groups :prevention groups(35 rats) and radiation groups. one classical radiation rat model which was locally irradiated with ⁶⁰Co y-rays was used, and the pathological chages were observed for 50 days after irradiation. We had used 5% DMSO to spread the skin irradiated with 40Gy ⁶⁰Co y-rays in the prevention groups from 1 hour before radiation to 11 days after radition. 5 rats in two groups at 3, 7, 14, 30, 50 days were killed and the specimens were obtained, 10 rats were killed as control groups. We study the expression of several growth factors(TGF-6, PDGF, VEGF) , free radical, cell apoptosis and apoptosis-realated genes by means of llight microscope, electron microscope, electron paramagnetic resonance(ESR), immunohistochemistry (IHC), image analysis, TDT-Mediated Biotion-dUTP Nick End Label ing (TUNED Results: 1) Radiation-induced skin ulcer were found on day 11 after irradiation,Skin ulcer in the radiation groups were enlarged and deeped gradually compared with the prevention groups during the observation period. 2)The wound healing was impairedby irradiation through prolonging the inflammatory stage, granulation forming early stage, granulation vigorous stage, granulation decrease stage. 3) Irradiationreduced the expression of several kinds of growth factors (PDGF, VEGF ). The degree of positive in the prevention groups was strongly compared with the radiation groups. 4) Meanwhile, the expression of TGFB1 was higher than that in prevention groups, especially in endothelial cells. 5) During day 14 to 30 after irradiation, the cell apoptosis rate (especially in the endothelial cells)in the radiation groups was higher than that in the prevention groups. P53 was over expressed during day 14 to 30 after irradiation, which was localized in vascular endotheliocytes and smooth muscle cells. Bax was moderately positive during day 11 to 28 and weakly positive during day 35 to 55, which was localized in vascular endotheliocytes, some fibroblasts and proliferating keratinocytes. Bcl-2 -. c-fos^ c-myc was weakly positive in day 3 to 7 after irradiation , and was located in keratinocytes, hair follicular cells and some vascular endotheliocytes. Bcl-2 was positive in dayl4 to 30, The degree of positive in the prevention groups was strongly compared with the radiation groups. Rb was weakly positive in day 3 to 30 after irradiation , and was located in keratinocytes, some fibroblasts and some vascular endotheliocytes. Bcl-2 was positive in day 50, The degree of positive in the both groups was no difference.Free radical increased rapidly after irradiation.it kept high level in day lto day 3. The levelof free radical in the prevention groups reduced clearly compared with the radiation groups.Conclusions:1)DMSO could reduce thr decreased expression of secrete endogenous growth factors, whicn in turn affect healing of radiation-induced skin ulcer. 2)After irradiation, the increased expression of the cell apoptosis rate and the apoptosis-realated protein P53, Bax, c-fos, c-myc, and the decreased expression of Bcl-2 might...