The Curative Effect Comparison Of Micro Plasma And Fractional Er: YAG Laser (2940nm) Of Hyperplastic Scar In Rabbit Ears

Objective: Micro plasma has been successfully used for tender skin andanti-wrinkle, dissolve fat, etc. Fractional laser on the curative effect ofsuperficial atrophic scar has been affirmation, but the treatment of hyperplasticscar are rarely reported. This experiment adopted for micro Plasma (Plasma)and fractional Er:YAG laser (2940nm) in the treatment of rabbit earhyperplastic scar, through observing the number of scar tissue fibroblasts,collagen configuration characteristic, and changes of exist ratio in collagentype Ⅰand Ⅲ, to study and compare the efficacy of both of hyperplastic scar,thus providing the theory basis for clinical working of micro Plasma and thefractional laser in treatment of Hypertrophic Scar.Methods: With the species of New Zealand white rabbit6, female,2.5±0.20kg weight. Using circular trephine along the long axis to avoid bloodvessels,4circular-shaped full-thickness skin defects of the diameter being8mm were made on each ear in the middle part of each ventral side rabbit ears,each wound intervals of1.5cm as deep as perichondrium. Six rabbits’ ears, atotal of48round wound formed42hyperplastic scar successfully.All thehyperplastic scar were randomly divided into3groups, the fractional lasergroup, the micro plasma group and the blank control group:①The treatment group of Plasma (n=14): building28days postoperati-vely, micro Plasma irradiation treatment. Treatment parameters: no casingtreatment head,0.6ms,80w. Harvesting of specimens after therapy for25days.②The treatment group of fractional Er:YAG laser (2940nm),(n=14):building28days postoperatively, lattice laser irradiation therapy. Treatmentparameters, the energy density of162J/cm2, repeat scanning5times.Harvesting of specimens after therapy for25days. ③The blank control group (n=14): compared with①②group, don’t doany treatment. Harvesting of specimens at the same time with the other tuogroups.The specimens were paraffin-embedded after dehydrated and dipped inparaffin, then were incided to slice, thickness of5μm. The number offibroblasts and distribution feature of collagen fiber were observed by HE,Masson and Sirius Scarlet staining of hypertrophic scar in rabbit ears in eachgroup; the ratio of collagen Ⅰ/Ⅲ was determinated by sirius red stain andpolarization microscopy method and image analysis technique in hypertrophicscar in rabbit ears of the experimental group.The number of fibroblasts and proportion of type Ⅲ collagen fibers werestatisticed on experimenta groups of hypertrophic scar in rabbit ears, and thedata were represented by the mean±standard deviation. the data wererepresented by the mean±standard deviation. SPSS13.0was used tocompletely randomized analysis of variance, with P <0.05as a standard ofjudging significant differences.Result:1Histomorphological changescontrol group：Scar tissue are red, hard, bumps on the skin surface, but notbeyond the original scope of operation field; Then under light microscope,The dermis are thickened, The fibroblast cells are obviously proliferated andarranged disorderly, capillaries are proliferated, collagen fibre were arrangedirregularly and distributed unevenly. vortex structure are visible.Plasma treatment group: Plasma treatment group: scar tissue becomeslighter, closer to the surrounding normal skin color.texture of scar tissuebecomes softer and smooth.Then under light microscope, The dermis isthinner than the control group and the numbers of the fibroblast cellsdecreased. collagen fiber is longer, thinner and arranged more regularly.fractional Er:YAG laser (2940nm) treatment group:The volume of scartissue are smaller,the colour of it are lighter than the control group.scar tissueis softer in texture,and the elasticity improved. Then under light microscope, the thickness of dermis and the numbers of the fibroblast cells decreased,arranged in order. The arrangement of collagen fiber are aparse and tend to bemore consistent.2polarization microscopy and image analysis:The polarization microscopy revealed distribution bundle、arrangementdisorder and uneven density of type I collagen fibers that showed yellow、largely, and contained roughly59.2%of the entire field of vision, whereastype Ⅲ collagen fibers consisted of green thin fibril with reticulation aroundtype I collagen, contained roughly40.8%in scar tissue of proliferation incontrol groups. Compared with the control group, collagen fibers arranged inorder, and was increased in the proportion of type Ⅲ collagen, about45.9%inthe plasma treatment group.In fractional Er:YAG laser (2940nm) treatmentgroup,the distribution of collagen fiber are sparse,and the arrangement of it aremore regular. collagen type Ⅲ ratio also increased significantly than controlgroup, about44.4%.3statistical analysisSpecimen groups in the number of fibroblasts and collagen type Ⅲproportion of completely randomized analysis of variance, the results showthat the three groups of specimens of hyperplastic scar, the microscopicfibroblast number per unit area was statistically difference (F=48.324, P=0.000<0.01); S-N-K method of multiple comparison, according to theresults of three groups of specimens in the overall mean differences betweenany two groups have statistical significance, can be thought of Plasma andfractional laser group than control group in unit area are to reduce the numberof fibroblasts, and the reduction of Plasma group is more obvious; Differenttreatment groups of rabbit ear hyperplastic scar tissue in the proportion ofcollagen type Ⅲ statistically significant (F=5.745, P=0.008<0.01); S-N-K method of multiple comparison results show that, in addition to the overallmean differences between Plasma and fractional laser group difference wasnot statistically significant, the rest of the overall mean similar between thetwo groups have statistical significance, Plasma and fractional laser group can be thought than the control group in the scar tissue collagen type Ⅲ ratio hasincreased, but the ratio between collagen type Ⅲ Plasma and fractional lasergroup, there is no obvious difference.Conclusion:1After plasma treatment, the scar tissue became soft and flat, its colorbecame eshallow, then we could see seriously the number of fibroblasts wasreducted distinctly, collagen fibers become evacuation, and shape andarrangement of the treatment group was more close to normal skin, collagentype Ⅲ proportion increased, Ⅰ/Ⅲ type collagen proportion is more closeto normal skin.2After fractional laser Er: YAG laser (2940nm) treatment, the scartissue elasticity increased, the thickness of the scar became thinner,microscopically, the numbers of fibroblasts was reductive, collagen fiber formand arrange was more closer to normal skin, and collagen type Ⅲ ratio wasincreased.3Being treated by micro plasma and fractional laser Er: YAG laser (2940nm), two treatment groups were compared with control group had obviouslyimproved.In allusion to the reduction of the number of fibroblasts,the Plasmagroup is more obvious. The collagen type Ⅲ proportion was increased thanthe control group but there was no significant difference between twotreatment groups.