Mechanisms and effects of biosynthesis and apoptosis in repair of full-thickness skin defect with collagen-chitosan dermal stent / 中华整形外科杂志

<p><b>OBJECTIVE</b>To investigate biosynthetic and apoptotic mechanisms in repair of full thickness skin defect with collagen-chitosan porous scaffold transplantation, and to determinate differences between wound repair with the scaffold transplantation and scar healing without the scaffold transplantation.</p><p><b>METHODS</b>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-beta1 expressions, apoptosis and self collagen replacement of scaffolds in wounds were detected in situ by immunohistochemical staining, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) and picrosirius red polarized light. Wounds without scaffold transplantation were studied as control.</p><p><b>RESULTS</b>1) Wounds with the scaffold transplantation were different from granulation tissue. 2) The peak of TGF-beta1 expression in the scaffold wounds was from 1 to 2 weeks after BDE transplantation, and TGF-beta1 expressions decreased continuously from 3 to 4 weeks. TGF-beta1 expressions increased continuously in the control wounds from 1 to 3 weeks and decreased on 4 weeks. TGF-beta1 expressions in the scaffold wounds on 1st and 2nd week were significantly higher than those in the corresponding control wounds, whereas, TGF-beta1 expressions in the scaffold wounds on 3rd and 4th week were significantly lower than those in the corresponding control wounds. 3) Apoptosis increased continuously in the scaffold wounds from 2 to 4 weeks after BDE transplantation, and so did in the control wounds from 3 to 4 weeks. However, apoptosis 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 week after BDE transplantation and those in the corresponding control wounds. 4) Observation by picrosirius red polarized light method: self collagen began to synthesize in the scaffold wounds on 1st week after BDE transplantation, and scaffolds had been replaced by self collagen from 2 to 3 weeks after BDE transplantation.</p><p><b>CONCLUSIONS</b>Collagen-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 scar healing. It has a good future in repairing skin defect.</p>

Study on repair of full-thickness skin defect with collagen-chitosan dermal stent in pigs / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate angiogenesis of collagen-chitosan porous scaffold, and to study survive of skin grafts on the scaffold after bilayer dermal equivalent (BDE) was transplanted on wounds with full thickness skin defects.</p><p><b>METHODS</b>The full thickness skin defects were made on 10 Bama miniature pigs and the BDE composed of collagen-chitosan porous scaffold and silicone membrane was transplanted on wound. Angiogenesis in dermal equivalent, wound healing, and healing and survive of skin grafts on dermal equivalent were observed in 1, 2, and 3 weeks after the BDE transplantation. At the same time, CD34 positive signals (neo-forming micro-vessels) were detected by immunohistochemical staining.</p><p><b>RESULTS</b>Inflammatory cells and fibroblasts infiltrated into dermal equivalent and a few new micro-vessels had been formed in 1 week after the BDE transplantation; neo-forming micro-vessels perpendicular to wound bed had increased significantly in 2 weeks after the BDE transplantation; neo-forming micro-vessels could be observed in almost all dermal equivalents in 3 weeks after the BDE transplantation. CD34 positive signals (neo-forming micro-vessels) in 3 weeks after the BDE transplantation was much more than those in 2 weeks after the BDE transplantation, and CD34 positive signals in 2 weeks after the BDE transplantation was much more than those in 1 week after the BDE transplantation. Survival rate of intermediate split thickness skin graft were 10%, 70% and 100% respectively after the skin grafts had been grafted for 2 weeks on surface of the scaffold which had been transplanted for 1, 2 and 3 weeks. Epidermis which had been grafted on surface of the scaffold for 1 or 2 weeks could perfectly survive after BDE had been transplanted for 1 or 2 weeks.</p><p><b>CONCLUSIONS</b>Collagen-chitosan porous scaffold plays a very important role in wound healing of full thickness skin defect and can induce fibroblast infiltration and new micro-vessel formation. Epidermis grafted on surface of collagen-chitosan porous scaffold can perfectly repair wounds, and it has brilliant applied prospects in repairing skin defect.</p>