重组胸腺素β4调节ICAM-1、MMP-2和LN-5促进创伤愈合的实验研究

目的探讨重组胸腺素[34（Thymosinβ4，Tβ4）通过改善创面基质环境促进大鼠皮肤创伤愈合的作用机制。方法在大鼠背部制作直径8mm的全层皮肤损伤模型，动物分为对照组（PBS）、Tβ4低剂量组、Tβ4中剂量组、Tβ4高剂量组，每组5只，每天两次给药，2d、4d、7d取材，行ICAM-1（Intercellul aradhesion molecule-1）、MMP-2（Matfix metallopoproteinase-2）、LN-5（Laminin-5）的免疫组化并进行平均积分光密度（IOD）分析。结果经Tβ4处理后的创面，ICAM-1阳性表达多，早期中、高剂量组表达较强（p〈0.01），中期均减弱，高剂量组相对较强；晚期各组表达增强，高剂量组最强（p〈0.01）。MMP-2早期对照组表达最高（p〈0.01），高剂量组最弱（P〈0.01）；中期中剂量组表达明显（p〈0.05）；晚期基质阳性明显增多，对照组表达最强（p〈0.01），高剂量组最弱（p〈0.01）。LN-5早期各组均可见较多的阳性表达，对照组与低剂量阳性强（P〈0.01），中剂量组阳性最少；中期中剂量组表达最强（p〈0.01）；晚期中剂量组仍然有较强的阳性表达（p〈0.01）。结论Tβ4可能是通过调节ICAM-1、MMP-2、LN-5的表达，改善创面基质环境，促进皮肤创伤愈合。

An Experimental Study: Recombinant Thymosin β4 Accelerates Skin Wound Healing by Regulating ICAM-1, MMP-2 and LN-5

Objective To study the mechanisms of recombinant thymosin β4 （Tβ4） accelerates skin wound healing in rats by regulating expression of ICAM-1,MMP-2 and LN-5, which are the key cytokines of ECM reforming. Methods Two full thickness 8 mm punch wounds were made on the dorsal surface each side of the rat. Tβ4 （Beijing Northland Biotech, China） was applied topically at the time of wounding （2 μg, 6 μg, 18μg in 50 μl PBS） and every 12h post-wounding. Control group received identical amounts of phosphate buffered saline （PBS） at the same time. At days 2, 4 and 7 post-wounding, materials were collected from wound tissue and fixed in 4 % paraformaldehyde for 24 h. The paraffin sections which from the middle of the wound were performed ICAM-1, MMP-2, LN-5 immunohistochemistry stain. This experiment was repeated twice using five rats for each test condition. Results Compared with control, ICAM-1 immuno-positive cells and vessels were the weakest at 4d post-wounding, higher positive at 2 d post-wounding and the peak positive at 7 d post-wounding while an excess expression in Tβ4 18μg group （p〈0.01）. MMP-2 immuno-stain were showed maintain high level, linear intensive density and lots of positive cells and ECM expressing in Tβ4 6μg group. LN-5 immunohistochemistry stain were showed a little more positive expressing early, including positive cells and ECM, but Tβ4 6μg group were expressed fewer, only at the borderline and bottom of the wound, while a significant increasing at 4d post-wounding （p 〈0.01） and a relative high expressing with cells in good directivity at 7d post-wounding （p〈0.01）. Conclusion Tβ4 may be modulate ICAM-1, MMP-2 and LN-5 proteic expression to regulate the reformation of ECM accelerating skin wound healing.