| Objective:The purpose of this study was to investigate whether adipose tissue extract combined with CO2fractional laser treatment of hypertrophic scar has a combined effect and its mechanism of action.It not only provides a laboratory basis for the sequential or combined treatment of the two methods in clinical use,but also provides a new clinical treatment scheme for hypertrophic scar.Methods:The waste adipose tissue was collected from patients undergoing liposuction in the Plastic Surgery Department of Zunyi Medical University Affiliated Hospital.The adipose tissue was washed,centrifuged,emulsified,freeze-thawed,and centrifuged again to obtain ATE,and then frozen for later use.Thirty-two rabbit ear hypertrophic scar models were prepared from 16 adult New Zealand rabbits weighing about 2.5±0.2 kg,and they were randomly divided into four groups with 8 models in each group:combination group（ATE combined with CO2fractional laser）,ATE group,CO2fractional Laser group and control group.Before treatment,30d,60d,and 90d after treatment,the scars in each group were evaluated by the Vancouver Scar Scale（VSS）,and photos of hypertrophic scars were taken with a digital camera to evaluate the changes in scar appearance.On the 30th and 90th days after treatment,the tissue samples were taken for HE staining and the scar hyperplasia index（HI）was measured,Masson staining to detect collagen deposition,immunohistochemistry to detect the expression ofα-SMA,and immunofluorescence staining to detect perilipoprotein to observe subcutaneous fat regeneration.Quantitative PCR was used to further detect the expression of adipogenic signal C/EBPαand PPARγm RNA.One-way analysis of variance was used to analyze the results.Results:1.Before the intervention,hypertrophic scars with red,raised and hard texture were seen.After the intervention,digital cameras were used to record the changes of the scars in the rabbit ears at different time points.On the 30th day,compared with the PBS group and the laser group,the scar in the combination group and the ATE group became flatter,narrowed,and the texture became softer;On the 60th day,the size of the scars in each group was reduced compared with the 30th day,and the improvement was the most obvious in the combination group;on the 90th day,the size,color and texture of the scars in the combined group were close to normal skin,while the red,stiff and raised scars were still seen in the PBS group.The VSS score showed that compared with before the intervention,the VSS score of each group decreased at each time point after the intervention,and the difference was statistically significant（p<0.05）.2.HE staining showed that on the 30th day,the PBS group had obvious scar hyperplasia,and a large number of inflammatory cells were infiltrated.The thickness of the epidermis and dermis in the combination group was significantly thinner,and the scar hyperplasia index decreased;On the 90th day,the thickness of epidermis and dermis in the combination group improved most obviously,the scar hyperplasia index was the lowest,and the inflammatory cell infiltration was the least.The scar hyperplasia index in the PBS group also decreased,but the improvement was not obvious（p<0.05）.3.Masson staining showed that on the 30th day,the collagen in the combined group and the ATE group were arranged regularly,while the collagen fibers in the laser group and the PBS group were dense and disorderly arranged;On the 90th day,the collagen arrangement in the combined group was the most loose and regular,while the dense and disordered collagen fibers were still seen in the PBS group（p<0.05）.4.Immunohistochemistry showed that on the 30th day,the expression ofα-SMA in the PBS group was significantly higher than that in the combination group;on the90th day,the expression ofα-SMA in each group decreased compared with the 30th day,and the combination group had the most significant decrease（p<0.05）.5.The results of immunofluorescence and q PCR showed that,no matter 30d or90d,the expression levels and expression levels of perilipin,C/EBPαand PPARγm RNA in the combined group were significantly higher than those in the other three groups,and the PBS group had the lowest expression level.Conclusion:ATE combined with CO2fractional laser can effectively improve hypertrophic scar,and the mechanism may be related to its induction of intra-scar adipogenic and promotion of extracellular matrix remodeling. |
