Study On The Effects And Mechanisms Of Biological Activity Of Hypoxia On Scar Fibroblast & The Changes And Mechanisms Of Hypoxic Environment In Scarring

Objective To explore the effects and mechanisms of biologicalactivity of hypoxia on dermal scar fibroblasts. Methods Dermal scarfibroblasts in vitro cultured for 3~4 days were placed in an incubator withlevels set at 20%,10%,5%,1.5%O2 and were removed at 24-h intervals forstudy.cell proliferation was determined by cell counting and PCNAexpression by immunohistochemical staining;Collagen type I expressionwas detected by immunohistochemical method;HIF-1αexpression wasdetected by immunohistochemical staining and Western Blot. ResultsWith the O2 concentrations decreasing,dermal scar fibroblast cellcounting was increased and the expressions of PCNA, collagen type I,HIF-1 α were strengthened gradually. HIF-1 α expression waspositively related to PCNA and collagen type I expression(P<0.01).Conclusions Hypoxia can induce dermal scar fibroblast proliferationand collagen type I expression.Decreasing hypoxia may be advantageousto prevent scar increase. HIF-1α may play an important role in theregulation of biological activity on dermal scar fibroblast under hypoxia.Objective To explore the changes and mechanisms ofmicrovasculation and hypoxic environment in dermal scars tissue fromincrease to maturation. Methods Expression of CD34,HIF-1α,VEGF,HO-1and p53 in burn wound granulation, scar of differentphases and normal skin were detected by immunohistochemical method.Expressions in epiderms and dermis were quantified by weightmethod,and microvessel count was done on base of the expression ofCD34, then the tissue structure ,microvasculation and all proteinexpressions were analyzed on the groups based on the position and thetime of scarring. Results As the time of scarring increasing,the total cellnumber and microvessel count were decreased,and the patency ofmicrovessels was gradually incresed.The expressions of HIF-1α,VEGFand HO-1 were gradually weakened with the scar maturation .but p53expression was gradually increased within the first year,then weakened.The expression of HIF-1αwas positively related to the expression ofVEGF and HO-1(P<0.01),but inversely to p53(P<0.01). ConclusionsIn the course of dermal scar maturation,the scar microvasculation isgradually ameliorated,and the hypoxia in scar is gradually decreased.Highdensity and high activity of cells are important factors for the formationof hypoxic environment in scarring. HIF-1αmay play a important role indecreasing hopxia,and promoting scar withered by regulating theexpression of VEGF , HO-1 and p53.