| Hyperplastic scar is a difficult problem expose to clinician . From the past investigation scientists have realized that radiotherapy could restrain the formation of Hyperplastic scar. Postoperative radiotherapy is becoming a major treatment for hypertrophic scar and keloid. Though series of clinical observation and basic stuty been done by some scholars,there's no study on the expression of several growth factors and no common criteria in used. As result, many radiation complication occurred in clinical practice.Objective: To study the pathological changes of different radiotherapeutics and the expression of several kinds of growth factors (TGF- , PDGF, FGF) and their receptors on wound healing in rats. At the same time we investigated the expression of several kinds of growth factors (TGF- ?, PDGF, FGF) and their receptors in the irradiated ECV304(human umbilical vein endothelial cells) and human embryo lung fibroblast. To discuss the role of radiotherapy with electronic Linear accelerator. So we should take right radiotherapeutics to inhibit scar forming .Methods: In this study, 36 Wistar rats were divived into four groups. Control group(9 rats) and Irradiation group(27 rats). We made two Full-thickness skin excision by surgery, in the dorsal aspect on every rat. Diameter on every wound is 15mm. Irradiation group(27 rats) were locally irradiated with electron accelerator. 1500cGy radiation dose was distributed to a rat model in five days among One group(9 rats). One group(9 rats) received 400cGy everyday and 5 times a week irradiation,the others received SOOcGy everyday and 3 times a week irradiation .All the rats were observation. At 2,5,7,10, 14, 21 days , two rats model in blank group were selected to been operated and the specimens were obtained .At 7, 10, 14, 17, 21, 28 days , we chose two rats from every irradiated groups to obtain specimens. We investigated the pathological alteration by macroscopic observation, light microscopy . the expression of several kinds of endogenous growth factors (TGF- , PDGF, FGF) and their receptors in specimens and inthe irradiated ECV304(human umbilical vein endothelial cells) and HELP(human embryo lung fibroblast) analyzed by means of immunohistochemical examinations, image analysis.Results: In our research , We found that: 1)The wound healing process was postponed by radiotherapy. The forming of collagen fibers were impaired by irradiation. 2) Irradiation reduced the expression of several kinds of growth factors (TGF-P 1, PDGF-A,bFGF) and receptors. 3) Meanwhile, the expression of growth factors (TGF-P 1, PDGF-A, bFGF) and receptors was higher in control group than that in Irradiated groups. During the first ten days the expression in the group, SOOcGy everyday and three times a week, is lower than others, but ten days later it kept in a high level compared with the others. 4) Day 14 to 28 after irradiation, collagen bundles is mainly composed of collagen type I, and there's little collagen type III. The quantity of the collagen in the group, which irradiated SOOcGy everyday and 5 times a week, be similar to that in control group. 5) In the group, SOOcGy once a day 5 times a week irradiation, the collagen fibres is thiner than that in other groups.6) After irradiation, the expression of several kinds of growth factors (TGF- P , PDGF, FGF) and their receptors in the ECV304(human umbilical vein endothelial cells) and HELP(human embryo lung fibroblast) were decreased obviously.Conclusions: 1) Electronic Linear accelerator irradiation could postpone the wound healing process, and reduce the producing of collagen fibres and extracellular matrix(ECM) , thereby restrain the Hyperplastic scar forming. 2) Irradiation could inhibit the secretion and biosynthesis,the growth factors and their receptors decreasing, therefore the proportion between proliferation and apoptosis unbalance.These may be one of the mechanism on radiotherapy using electron accelerator. 3) The effect of radiotherapy is associated with single dose of the irradiation. From our experiment,... |
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