Changes And Mechanisms Of Tissue Oxygen Partial Pressure In Rabbit Ear Scars From Formation To Maturation

Purpose:To explore the changes and mechanisms of tissue oxygen partial pressure in rabbit ear scars from formation to maturation and find good methods for treating scars.Methods:Animal models with rabbit ear scars were made from their formation to maturation .The scars tissue oxygen partial pressure were measured with TCM4 at 14-day post-operation, 30-day post-operation, 60-day post-operation, and 90-day post-operation respectively, and the normal skins tissue oxygen partial pressure were measured as comparision.Different period scars and normal skin tissue samples were collected to make histopathologic examination and detect the expression of HIF-1αand VEGF with immunohistochemistry. The changes of tissue oxygen partial pressure and the scars tissue structure and the regulations of the expression of HIF-1αand VEGF were observed. The relativities between oxygen partial pressure and the expression of VEGF and HIF-1αwere analyzed.Results:1. The changes of tissue oxygen partial pressure. Granulation tissue oxygen tension was below scars groups (p<0.01), the 30th day post-operation group oxygen partial pressure was lower than the 60-day group (p<0.01), the 60-day group oxygen partial pressure was lower than the 90-day group (p<0.01); the 90-day group and the normal skin were without statistical significance (p>0.05).2. The changes of scars tissue structures. There were lots of phlogistic cells and palingenetic blood vessels in granulation tissues. A large number of fibroblasts and capillary were found in the scar tissue of 30-day post-operation. Microvasculars and fibroblasts were relatively reduced in the cases of the 60-day post-operation . The scar tissue structure was close to normal skins in the cases of the 90-day post-operation. 3. HIF-1αstaining particles in the granulation tissue was located in the nucleus and the expression was significantly higher than the scar group (P<0.01). In the 30-day scar group the HIF-1αexpression level of positive particles was higher than the 60-day scar group (p<0.01); and the HIF-1αexpression level of positive particles in the 60-day scar group was higher than the 90-day scar group (p<0.01); there was no statistically significant difference to the 90-day scar group, compared with normal skin (p>0.05).4. VEGF staining particles in the granulation tissue was located in the cytoplasm and the expression intensity was significantly higher than that scar group (P<0.01). The expression of VEGF-positive particles in the 30-day scar group was higher than the 60-day scar group (p<0.01);the expression of VEGF-positive particles in the 60-day scar group was higher than the 90 days scar group (p<0.01);the 90-day group was not statistical significant different from normal skins (p>0.05).5. The correlativities between oxygen partial pressure and the expression of HIF-1αand VEGF. In the process of scars maturation it showed a negative correlation between oxygen partial pressure and the expression of HIF-1α(r=-0.92, P<0.01); and a negative correlation with the expression of VEGF (r=-0.88, P<0.01). However, The expression of HIF-1αwas positively correlated with VEGF (r=0.97, p<0.01).Conclusion1. With time going on., the scar tissue oxygen partial pressure increases gradually, and the scar is also gradually shrinking.2. Improving oxygen partial pressure may contribute to the maturation of scars.3. HIF-1αand VEGF may play important regulatory roles in the process of changes of scars tissue oxygen partial pressure.