| Objective:Through treating the hypertrophic scar of hypertrophic scars in the rabbit ear model by Fractional CO2 laser combined with autologous granule fat injection,we observed the morphological and histological changes,compared the expression ofα-SMA,type I andⅢcollagen and in different groups,in order to find that whether autologous granule fat can supplement the stem cells to hypertrophic scar tissue,and whether Fractional CO2 laser combined with autologous granule fat injection can inhibit scar from growing and recover the function of skin more efficiently.Method:1.New Zealand white rabbits,15,were manufactured hypertrophic scar model（HSM）on the rabbit ears,each ear make 4HSMs,we total harvested 120 HSMs.HSMs were randomly divided into4 groups,that is the combination group（Group A）,fat injected group（Group B）,laser treated group（Group C）,and scar control group（Group D）,each group contain 30 HSMs,and we take 30 pieces of normal skin as Group E.2.Extraction and injection of autologous granule fat:After 28 days modeled,we cut down the body fat of rabbits under their groin,removed the visible vessels and connective tissue,rinsed the fat 3 times with PBS buffer which contains antibiotic.Then the fat tissue were cut into paste using surgical scissors.We injected the fat paste into Group A and group B,group C and group D were not injected.3.Fractional CO2 laser therapy:（DeepFx:Fluence:15mJ,Frequency:300Hz,Shape:2,Size:8,Pulse:1,Density:5%）:After injection fat tissue,we treated group A and group C with Fractional CO2 laser,group B and group D were not treated.4.Specimen Collection:Observed the morphological changes of scar,and took biopsy and reserved by embedding in paraffin,after treatment 3days,7 days,14 days,21 days,28 days.5.Evaluate the result:Using HE staining to observation the histological changes of hypertrophic scar,and immunohistochemistry to observation the changes of expression ofα-SMA,type I andⅢcollagen.6.Statistics analysis:The resulting data were analyzed using SPSS20.0,and using the analysis of Chi-square test,According toα=0.05,p<0.05 was used as the criterion to judge the difference.Result:1.The general observation:After 28 days modeled,all the wounds were healed and formed red,hard,protruding hypertrophic scar.After treating,the average thickness of group A and B increased,then,the average thickness decreased over time,the texture become tender,the color become lighter.The scar of group C shriveled,the scar become smaller,flatter,softer and lighter.The scar of group D kept growing.2.Histological observation:HE dyeing:the dermis of scars were thickened,a large number of fiber cells,inflammatory cells and blood vessels can be seen in the scar.The collagen were dense and disorganized like nodular and helical structure,the skin appendage were disappeared.After treatment,the scar of group A,B,C can change into normal skin in different degrees,it was not shown in group D.3.Special dyeing observation:After immunohistochemical staining.（1）The expression ofα-SMA increased in all scars.After treatment,the expression ofα-SMA was significantly decreased in group A,B,C,differences of each group were significantly compared with themselves（P<0.05）,while group D were not significant（P>0.05）.Further,after 28 days of treatment,A,B,and C were compared with each other,the decreased degree of group A was the largest,followed by group C and group B.The difference between group A and group B was significantly（P<0.05）,while the differences between group A and group B（P>0.05）,group B and group C（P>0.05）were not significantly.（2）After modeled,the type I Collagen increased in scar obviously compared with the normal skin.After treatment,type I Collagen in group D decreased slowly,while fast in group A,B,and C,Compared with the expression between 3 days and 28 days,the differences were significant in group A,B and C（P<0.05）,not in group D（P>0.05）.At 28 days,the degree of decreasing of type I Collagen of group A is the largest,followed by group C,B and D,the difference between group A and B is significant（P<0.05）,while not between group A and C,group B and C（P>0.05）.（3）After modeled,the type III Collagen increased in scar obviously compared with the normal skin.After treatment,type III Collagen decreased in all groups,and the degree of decreasing of type III Collagen of group A is the largest,followed by group C,B and D.Compared with the expression between 3 days and 28 days,the differences were significant in group A（P<0.05）,not in group B,C and D（P>0.05）.Conclusions:1.Fractional CO2 laser combined with autologous granule fat injection can ameliorate the number of fibroblasts,morphology,density,arrangement of collagen,vascular proliferation,inflammatory cell infiltration and reduce the expression ofα-SMA andⅠ,Ⅲcollagen,The effect is better than single autologous granule fat injection and single Fractional CO2 laser.2.Autologous granule fat injection may supply the stem cells in scars,enhance the ability of self-recovery.3.After the injection of autologous granule fat,Fractional CO2 laser may stimulate the proliferation and differentiation of adipose derived stem cells more efficiently,stimulate the self-recovery in-situ of skin. |
