Mechanism Of Lipolytic And Smooth Effects Of D980-nm Laser With Different Treatment Frequencies On Skin Tissue In Rats

Objective: To analyze the efficacy of D980-nm laser treatment with different frequencies on the structure of rats’ skin,dermal thickness,fibroblast and the expression of TGF-β1 and bFGF,to analyze the differences between different treatment frequencies,and to determine the efficacy of D980-nm laser in dissolving fat and rejuvenating skin,in order to provide theoretical basis and clues for clinical skin remodeling treatment.Methods: Eighteen 12-14 month-old male Sprague-Dawley rats,weighing 400~450g,were randomly divided into 3 groups(n=6).The rat skin at the left side was exposed to D980-nm laser irradiation at a density of 20J/cm2,a power of 8W,a pulse width of 20 ms and a pulse frequency of 40 Hz for 1 time(group I),2 times of 5-minute interval(group II),and 3 times of 5-minute interval(group III)as a treatment course,for 4 treatment courses with an interval of 1 week;the other side of the skin was not treated as the control groups(groups I1,II1,and III1,respectively).After 8 weeks,the skin was harvested for HE staining and immunohistochemical staining to observe the structure changes of skin,to measure the dermal thickness,to count the number of fibroblasts,and detect the expressions of transforming growth factor β1(TGF-β1)and basic fibroblast growth factor(bFGF).Results: Compared with groups I1,II1,and III1,the skin structure was significantly improved in groups I,II,and III.After D980-nm laser irradiation,the number of fat cells decreased;local angiogenesis was observed;the total number of fibroblasts and fibers increased;the collagen fiber had large diameter,and arranged closely and regularly;the dermal thickness and the number of the fibroblasts increased;and the expressions of TGF-β1 and bFGF significantly enhanced,showing significant differences(P<0.05).With increased D980-nm laser irradiation times,the above indexes increased,showing significant differences between group III and groups I,II(P<0.05).Conclusions: D980-nm laser treatment has lipolytic and tender effect on the skin,and the frequency of the treatment is an important factor in skin rejuvenation.And that shows the different frequencies of the treatment can produce different reaction,associated with the organization effect and cellular effect of laser.