生物合成与细胞凋亡在胶原-壳聚糖真皮支架修复创面中的作用和机制

目的 探讨胶原一壳聚糖真皮支架在修复全层皮肤缺损的生物合成和细胞凋亡机制,并明确支架植入修复创面与无支架植入的瘢痕修复创面的区别.方法 将胶原-壳聚糖,硅橡胶双层人工真皮支架移植于猪全层皮肤缺损创面,对植入后1、2、3周及植入支架2周加植表皮后2周的创面和修复情况进行观察.同时,通过免疫组织化学、末端脱氧核苷酸介导的生物素化的脱氧尿嘧啶DNA切口末端标记、天狼猩红染色方法,对不同时间的创面的TGF-β1.的表达、细胞凋亡发生情况以及支架自身胶原替代进行检测和观察.以不植入支架的创面为对照.结果 ①实验组创面与正常肉芽组织不同.②TGF-β1在实验组表达高峰在支架植入后1、2周,3-4周持续下降;在对照组中,1～3周的创面持续升高,4周下降.组问比较,1、2周实验组明显高于相应对照组,3、4周实验组明显低于相应对照组.③实验组植入支架后2-4周,细胞凋亡持续增多;对照组3-4周创面细胞凋亡持续增多.组间比较,l周两者差异无统计学意义,2-4周实验组显著高于相应对照组.④天狼猩红染色观察:实验组1周,自身胶原已开始合成,2-3周基本完成支架自身胶原替代.结论 胶原-壳聚糖真皮支架在伤口愈合中有明显作用,其修复创面的机制与自然的肉芽或瘢痕修复不同.

Mechanisms and effects of biosynthesis and apoptosis in repair of full-thickness skin defect with collagen-chitosan dermal stent

Objective To investigate biosynthetic and apoptotic mechanisms in repair of full thickness skin defect with collagan-chitosan porous scaffold transplantation, and to determinate differences between wound repair with the scaffold transplantation and scar healing without the scaffold transplantation. Methods The full thickness skin defects were made on 10 Bama miniature pigs and the bilayer dermal equivalent (BDE) composed of collagen-chitosan porous scaffold and silicone membrane was transplanted on wounds. Surfaces of wounds were observed at 1,2, and 3 weeks after the BDE transplantation, and so were done the wound repairs after epidermis had been grafted for 2 weeks on surface of the scaffold which had been transplanted on skin defect wounds for 2 weeks. At the same time, TGF-β1 expressions, apoptosis and serf collagen replacement of scaffolds in wounds were detected in situ by immunohistochemical staining, terminal deoxyuneleotidyl transferase-mediated deoxyuridinctriphosphate-biotin nick end labeling (TUNEL) and picrosirius red polarized light. Wounds without after BDE transplantation, and TGF-β1 expressions decreased continuously from 3 to 4 weeks. TGF-β1 expressions increased continuously in the control wounds from 1 to 3 weeks and decreased on 4 weeks. TGF-β1 expressions in the scaffold wounds on 1st and 2nd week were significantly higher than those in the corresponding control wounds, whereas, TGF-β1 expressions in the scaffold wounds on 3rd and 4th week were significantly lower than those in the BDE transplantation, and so did in the control wounds from 3 to 4 weeks. However, apoptnsis signals in the scaffold wounds on 2nd, 3rd, and 4th week after BDE transplantation were significantly more than those in the corresponding control wounds, and there was no difference between apoptosis signals in the scaffold wounds on 1st polarized light method: self collagen began to synthesize in the scaffold wounds on 1st week after BDE transplantation, and scaffolds had been replaced by serf collagen from 2 to 3 weeks after BDE transplantation. Conclusions CoUagen-chitosan porous scaffold plays a very important role in wound healing of full thickness skin defect. The mechanisms of wound repair by dermal scaffold are different from those by granulation and sear healing. It has a good future in repairing skin defect.