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目的观察不同创面血小板源性生长因子(PDGF)A及其受体(PDGFR)α的动态表达,探讨急性放射性皮肤溃疡难愈合的机制。方法应用γ射线单次照射Wistar大鼠,制作急性放射性皮肤溃疡模型(照射组,55只),以皮肤全层切割伤模型大鼠作为创伤对照(创伤组,55只),另取5只正常大鼠作为对照组。采用免疫组织化学及原位逆转录-聚合酶链反应(RT-PCR)等方法,观察不同时相点各组大鼠创面内PDGF-A、PDGFR-α和PDGF-AmRNA的表达。结果对照组大鼠皮肤中PDGF-A及PDGFR-α表达为阴性;创伤组大鼠炎症反应期及肉芽组织期(伤后3~9d)PDGF-A的积分吸光度(IA)值为20.0±1.6、28.3±1.0;照射组炎症反应期及肉芽组织期(伤后14~28d)其PDGF-A的IA值各为14.0±1.2、20.3±1.2,PDGF-A及PDGFR-α和PDGF-AmRNA的表达较创伤组明显减弱,至瘢痕形成期(伤后55d)时表达进一步减弱。结论急性放射性皮肤溃疡内PDGF-A及PDGFR-α的表达减弱,可能是创面难愈合的机制之一。
Objective To observe the dynamic expression of platelet derived growth factor (PDGFR) α and its receptor α (PDGFR α) in different wounds and to explore the mechanism of refractory acute radiation-induced skin ulcer healing. Methods Acute radiation-induced skin ulcer model was established by irradiation with γ-rays (irradiation group, 55 rats). Whole-thickness cutaneous wounds were used as trauma control (55 trauma patients) and 5 normal Rats served as control group. Immunohistochemistry and in situ reverse transcription-polymerase chain reaction (RT-PCR) were used to observe the expression of PDGF-A, PDGFR-α and PDGF-AmRNA in wounds of rats in different time points. Results The expression of PDGF-A and PDGFR-α in the skin of the rats in the control group was negative. The integral absorbance (PD) of PDGF-A in the inflammatory reaction and granulation tissues (3-9 days after injury) in the trauma group was 20.0 ± 1.6 , 28.3 ± 1.0 respectively. The IA values of PDGF-A in the inflammatory response and granulation tissues (14 ~ 28 d after injury) were 14.0 ± 1.2 and 20.3 ± 1.2 respectively in PD group, PDGF-A and PDGFR-α and PDGF-AmRNA Compared with the traumatic group, the expression was significantly weakened and further decreased to the stage of scarring (55d after injury). Conclusion The decreased expression of PDGF-A and PDGFR-α in acute radiation-induced skin ulcers may be one of the mechanisms of refractory wound healing.