【摘要】 目的:探讨加速器照射后大鼠皮肤伤口愈合过程中血小板源性生长因子及其受体表达与胶原形成的规律。方法:实验于2002-05/2003-06在解放军军事医学科学院附属医院放疗科及解放军军事医学科学院放射医学研究所病理室完成。清洁级雄性Wistar大鼠36只,体质量(200±20)g,随机数字法分为4组,每组9只,1组作为空白对照组,3组作为照射组。在每只大鼠背部脊柱两侧切2个圆形创面,创面直径1.5cm,深达皮下组织全层,2个创面间隔1.5cm。处理完毕后以无菌纱布包扎伤口,动物置于单笼饲养。术后48h,照射组大鼠背部创口以直线加速器6MeV电子线照射,分组300cGy组(300cGy/(次·d),连续照射5次)、400cGy组(400cGy/(次·d),连续照射5次)和500cGy组(500cGy/(次·d),隔日1次,连续照射3次),照射剂量率为240cGy/min。观察创面愈合及渗出情况。对照组分别于致伤后2,5,7,10,14,21d麻醉后取材,照射组均在伤后7,10,14,17,21,28d取材。常规苏木精-伊红染色病理组织学观察、天狼猩红染色后偏光镜观察胶原纤维含量变化、免疫组化方法和图象分析定性和定量检测各组伤口愈合过程中胶原纤维和血小板源性生长因子及其受体表达的动态变化。结果:实验大鼠36只均进入结果分析。①照射组创面愈合延迟,对照组创面平均11d全部愈合,照射组平均14d愈合。②照射组肉芽组织产生和胶原纤维的合成受抑制,300cGy照射组较其他各组胶原纤维细小,排列稀疏。28d图像分析胶原积分吸光度300cGy组、400cGy组、500cGy组分别为(0.323±0.015,0.349±0.012,0.457±0.019),组间比较差异有显著性(P<0.05)。③照射组血小板源性生长因子-A及受体表达伤后10～14d达到高峰,对照组7～10d达到高峰。各时间点300cGy组与400cGy组差异不明显(P>0.05),500cGy组高峰出现最晚,后期较其他组显著升高(P<0.05)。结论:直线加速器照射抑制血小板源性生长因子及其受体表达,并与胶原形成的效果与照射剂量有关,应用低剂量分次照射防治瘢痕增生是很好的选择。更多还原

【Abstract】 AIM: To study the correlation of platelet-derived growth factor (PDGF) and the expression of its receptor with the producing of collagen during wound healing of rats after irradiation. METHODS: The experiment was conducted in the Department of Radiotherapy and Institute of Radiation Medicine, Academy of Military Medical Sciences between May 2002 and June 2003. Thirty-six clean grade healthy male Wistar rats (200±20) g were randomly divided into 4 groups with 9 rats in each group and one group served as blank control, and the others as irradiation group. The rats were subjected to two round full-thickness skin excisions with 1.5 cm in diameter and 1.5 cm distance between the two wound in the dorsal aspect. After wrapping with sterile gauze, the rats were feed separately. Forty-eight hours after operation, the rats in the irradiation group were locally irradiated with 6 MeV electron accelerator and divided into 300 cGy group (300 cGy every time daily for 5 times), 400 cGy group (400 cGy every time daily for 5 times) and 500 cGy group (300 cGy once every two days for 3 times) with the irradiation dose of 240 cGy per minute. The wound healing and exudation condition were observed. The control group were sampled at 2, 5, 7, 10, 14 and 21 days after injury; the irradiation group were sampled at 7, 10, 14, 17, 21 and 28 days after injury. The collagen fibrils changes were observed by polarizing glass after HE staining, pathohistological observation and picrosirius staining. The dynamic changes in the expression of PDGF and its receptor during wound healing were detected by means of immunohistochemical examinations and image analysis. RESULTS: All the 36 rats were involved in the result analysis. ①The wound healing process was postponed by radiotherapy; the wound of the control group totally healed after 11 days, but the irradiation group healed after 14 days. ②The produce of granulation tissue and collagen fibers were inhibited by radiotherapy; the collagen fibers of the 300 cGy irradiation group were smaller than other groups, which arranged rarely. The 28 days image analysis showed that the collagen integral absorbance of 300, 400 and 500 cGy irradiation groups were (0.323±0.015, 0.349±0.012, 0.457±0.019), respectively, and there were significant differences between groups (P < 0.05). ③The expression of PDGF-A and its receptor of the irradiation group reached the peak at 10-14 days after injury, but the control group at 7-10 days. No obvious difference was found in the 300 and 400 cGy irradiation groups at each time point (P > 0.05); the 500 cGy irradiation group was the latest one to reach the peak, and at the late period, the expressions were significantly increased (P < 0.05). CONCLUSION: The electron accelerator irradiation can inhibit the expression of PDGF and its receptor, and the producing of collagen is related with irradiation dose. The irradiation with low dose electron beam is a better choice to prevent and cure scar hyperplasy.更多还原