重组胸腺素β4通过调节血管内皮生长因子、碱性成纤维细胞生长因子促进皮肤创伤愈合

Recombinant thymosin beta 4 accelerates skin wound healing by regulating vascular endothelial growth factor and basic fibroblast growth factor expression

背景:由于机体自身修复愈合的能力极其有限,一旦发生损伤或者病变很难自愈。近年来,胸腺素β4促进创伤愈合的作用受到关注,为创伤愈合药物的研究提供了一个新方向。目的:通过制作大鼠皮肤全层创伤模型,观察局部给予重组胸腺素β4对创面血管内皮生长因子和碱性成纤维细胞生长因子表达的调节作用,并分析其剂量效应。设计、时间及地点:细胞因子水平的随机对照动物实验,于2007-03/2008-01在南开大学医学院解剖教研室完成。材料:胸腺素β4由北京诺思兰德生物技术有限公司提供。方法:纳入雄性SD大鼠60只,采用直径8mm的自制打孔器在大鼠脊柱两侧脊肋角处各制备1个全层皮肤缺损模型。将大鼠随机分为胸腺素β440,120,360mg/L组及对照组,每组15只。分别于模型制备后即刻、每天早7:00、晚7:00给每个伤口表面滴加相应剂量的胸腺素β450μL及等量磷酸盐缓冲液。主要观察指标:于造模后2,4,7d,每组每时相点取5只大鼠背部全层皮肤标本行苏木精-伊红和三原染色观察组织形态学变化,采用免疫组织化学法检测血管内皮生长因子及碱性成纤维细胞生长因子的表达。结果:创面组织形态观察结果示,与对照组相比,胸腺素β4各剂量组造模后毛细血管增多,成纤维细胞、胶原纤维、网状纤维增多,排列较规则,以胸腺素β4120mg/L组最明显。胸腺素β4处理后4d血管内皮生长因子表达最多,造模后7d表达减少,胸腺素β4120mg/L组血管内皮生长因子表达强度保持在较高水平,阳性血管面积大于40,360mg/L组(P<0.05～0.01)。胸腺素β4120mg/L组造模后2d碱性成纤维细胞生长因子表达较强,造模后4,7d表达逐渐减弱(P<0.01)。结论:实验中120mg/L胸腺素β4可使血管内皮生长因子、碱性成纤维细胞生长因子持续稳定较高表达。在愈合早期促进血管再生,促进肉芽组织生长和成纤维细胞的增殖、分化,在愈合晚期,下调血管内皮生长因子的表达,同时抑制碱性成纤维细胞生长因子过度表达。

BACKGROUND： It is difficult to heal when damage or pathological changes occurred due to the limited self-repair ability. Recently researchers have paid close attention to thymosin β 4 （T β 4） in promoting wound healing, which designates a direction for the pharmaprojects on wound healing. OBJECTIVE： To study the mechanisms of recombinant Tβ 4 accelerates skin wound healing in rats by regulation expression of vascular endothelial growth factor （VEGF） and basic fibroblast growth factor （bFGF）. DESIGN, TIME AND SETTING： The randomized controlled animal study based on genes was performed at the Anatomy Department Nankal University School of Medicine from March 2007 to January 2008. MATERIALS： Tβ4 was supplied by Beijing Northland Biotech.Co., Ltd. METHODS： Sixty male Sprague-Dawley rats were selected and prepared for full thickness skin defect animal models by using self-made puncher with 8 mm diameter on the each side of vertebral colunm at the costovertebral angle, then divided into the control and Tβ4 40,120, 360 mg/L groups randomly （n=15）. 50μL Tβ4saline were injected on the surface of wound immediately at 7：00 am and 7：00 pm every day after models preparation. MAIN OUTCOME MEASURES： Histological changes were observed by hematoxylin-eosin staining and Marson staining at 2, 4, 7 days after models preparation, VEGF and bFGF expression were detected by immunohistochemical method. RESULTS： Immunohistochemistry staining showed that compared with the control group, capillaries, VEGF, collagen fiber and reticular fiber were increased with regular arrangements in Tβ4 groups, especially that of 120 mg/L T β4 group. The expression of VEGF reached a peak level at 4 days after treating with T β4, and decreased at 7 days, however, the expression of VEGF remained higher in the 120 mg/L Tβ4 group than 40 and 360 mg/L Tβ4 groups （P 〈 0.05-0.01）. The bFGF expression elevated at 2 days after modeling, and then gradually decreased at 4, 7 days in the 120 mg/L Tβ4 group （P 〈 0.01）. CONCLUSION： 120 mg/L Tβ4 can regulate the high expression of VEGF and bFGF sustainable and stablely, which can accelerate skin wound healing by the promoting vascular regeneration and proliferation of granulation tissue and bFGF at early stage, and down-regulated the expression of VEGF, inhibit over-expression of bFGF at the later stage of healing.