RESUMO
OBJECTIVE: To investigate the effects of vascular endothelial growth factor (VEGF) DNA plasmids, encoded in collagen-sulfonated carboxymethyl chitosan porous scaffold, on the angiogenesis in full-thickness burn wounds. METHODS: Wounds and pathological changes were observed at Week 1, 2, 3 and 4 after pure collagen-sulfonated carboxymethyl chitosan porous scaffold (group A) and collagen-sulfonated carboxymethyl chitosan porous scaffold encoding VEGF DNA plasmids (group B) were transplanted onto eachar-removed wounds of full-thickness burn in 6 Bama miniature pigs respectively. Wound healing was observed by pathologic slides after epidermal grafting for 2 weeks (at Week 4) onto the surface of different dermal scaffolds transplanted on wounds for 2 weeks. At the same time, new-forming vessels expressing CD31 and mature vessels expressing α-SMA (α-smooth muscle actin) and the expression of VEGF in wounds at Week 1, 2, 3 and 4 were detected in situ by immunohistochemical staining. The burn wounds without any transplanted scaffold (group C) were studied as the controls. RESULTS: Wounds with various scaffolds were different from those without any scaffold. Angiogenesis of the group B was better than that of the group A. Neo-forming micro-vessels expressing CD31 in the wounds of group A or B at Week 1, 2, 3 and 4 were as follows: 18.7 ± 3.1, 25.7 ± 2.3, 36.8 ± 2.5 & 26.2 ± 2.9; 24.5 ± 3.8, 32.3 ± 2.8, 39.2 ± 2.2 & 27.3 ± 3.0. Mature vessels expressing α-SMA: 11.7 ± 1.9, 20.5 ± 1.9, 35.0 ± 4.5 & 24.0 ± 2.8; 20.2 ± 3.1, 33.5 ± 3.7, 38.2 ± 4.5 & 26.5 ± 2.3. The expressions of VEGF: 48.7 ± 7.9, 141.7 ± 9.1, 201.5 ± 8.6 & 107.0 ± 8.2; 97.3 ± 7.9, 172.3 ± 8.1, 208.7 ± 8.3 & 114.0 ± 5.8. Expressing intensity of CD31, α-SMA and VEGF in the wounds of group C at Week 1, 2, 3 & 4: 6.0 ± 2.0, 9.8 ± 3.4, 19.3 ± 2.5 & 18.7 ± 2.2; 3.7 ± 2.0, 8.7 ± 1.8, 13.0 ± 2.5 & 14.0 ± 2.8; 3.5 ± 2.3, 10.3 ± 3.5, 23.0 ± 5.6 & 21.5 ± 5.1. There were significant statistical differences among three groups. CONCLUSION: Artificial dermal scaffold encoding exogenous pDNA-VEGF can promote a quicker angiogenesis through a high expression of VEGF. Thus a full-thickness burn wound may be better repaired.
