Effect Of2940nm Erbium Fractional Laser On VEGF In Rabbit Ear’s Hypertrophic Scar

BackgroundAs is known to all, Hypertrophic scar has been perplexing the doctor and patient,especially for the plastic surgeon and dermatological surgeons faced major challenges. Hypertrophic scar (HS) is mainly composed of fibroblasts proliferation and excessive accumulation of collagen and chronic inflammation that leads to excessive growth due to capillary. Operation, burns, trauma after the accident may be the formation of HS, inducing factors of infection, foreign body and its formation, Millions of people around the world suffered from its harm every year. In treatment, most of the studies tend to form drug prevention of HS, this does not reflect its therapeutic effect.To treat scar began in1835, is mainly used in pressure therapy, gradually developed into the silicone gel film, local corticosteroid injection, retinoic acid, transplantation, surgical resection, radiation, freezing5-FU,IFN treatments and combination therapy, The effect of the combined treatment is superior to the single use a treatment effect, but there are still some side effect, for example,like pain, skin atrophy, pigmentation, high recurrence rate and so on. In order to allow patients to achieve more satisfactory curative effect, domestic and international scholar found a new treatment, it is laser treatment. CO2laser was first used in the treatment of hyperplastic scar, but the recurrence rate is higher than90%, and there are many side effects like erythema, exudation, discomfort. so the clinic has basically been replaced by other methods now. There are individual application of intense pulsed laser (IPL) in treating hyperplastic scar reports, the effectiveness of the treatment has not been confirmed. Pulsed dye laser (PDL), is considered to be the most effective method of laser treatment, but the individual reported in randomized studies, produce erythema and other side effects, and the validity is only in the lower (low0-33%improvement, improvement in34-66%), but the therapeutic effect may be related with the wavelength of laser.2940nm erbium fractional laser treatment of hyperplastic scar to see a report, but its therapeutic mechanism is unknown.After many researchers constant exploration and practice, think laser combined with other therapies may be the best choice, but hypertrophic scar formation mechanism is complex, the specific mechanism of laser on the treatment effect is still not clear. Research that the main principle of laser treatment of hyperplastic scar by the laser cauterization, vaporization, cutting, coagulation and defocus technique to remove scar tissue or injury scar vessels, inhibit the synthesis of collagen, the inhibitory and induction of apoptosis of fibroblast proliferation. In order to better understand the formation mechanism and find the better treatment of hyperplastic scar, researchers studied a lot of infrastructure, as basic research requires a large sample, so now generally adopts the method of making animal model to study. At present, people mainly developed3kinds of animal models:mice model, the rabbit ear model and the female Duroc pig model. The nude mice model of human HS tissue is transplanted into nude mice, the drawback is the formation of HS, not dynamic observation is not itself, in order to overcome these shortcomings, researchers use the big white rabbit, caused by defects in the ventral side of the ear, and natural healing shaped hypertrophic scar, observed from on histology of wound of rabbit ears, can be produced with human HS proliferation block is similar to basic research, so this method is widely used in hypertrophic scar. Based on this, this study aimed at application of hypertrophic scar of rabbit ear model was used to study the effect of2940nm erbium fractional laser in hypertrophic scar, further explore its mechanism of action.ObjectiveIn this paper,we use the model of hypertrophic scar in rabbits, to observe effect of2940nm erbium fractional laser on VEGF in rabbit ear, s hypertrophic scar respectively in the eye, HE staining, immunohistochemical staining.Methods1Establishment and block the formation of hypertrophic scar in rabbits:37New Zealand white rabbits, before the experiment use razor to the ventral of rabbit ear hair removal, with2ml:0.1g ketamine hydrochloride injection (30mg/kg) ear vein of rabbit ear after anesthesia, the ventral surface of the skin of ethanol disinfection. Avoid visible vessels,and drill out the5round lesions with9mm trephine, the skin lesions of the region together with the cartilage membrane skin removal, retained cartilage, a total of370wound. Treated with erythromycin eye ointment coating on skin infection prevention and observe the wound healing and scar formation time, the rabbit ear scar formation model, random per rabbit ear scar given5different treatments:negative control group (without treatment of scar in scar surface and the natural growth), laser treatment group (2940nm erbium fractional laser treatment).2Morphological observation:24New Zealand white rabbits, laser treatment group and control group with12rats in each group. After giving the scar surface treated by different way in7,14,30day general observation of rabbit ear scar hyperplasia, also with a vernier caliper, measured before and after the treatment, in7,14,30days around the scar thickness and4time points scar thickness in normal skin, scar thickness/normal skin thickness said the scar elevation index (SEI) of scar.3Histological observation:after laser was given to seventh, scar different treatment in7,14,30days each take12scar tissue, in control group at different time points and scar natural growth after70days each take12scar tissue, samples were fixed by10%formaldehyde solution for24h ethanol dehydration, paraffin embedding, slice, HE dyeing observation With leika image analyzer, measure the vascular surface density in the scar area (total area of blood vessels/field) and number density (number of vessels/field scar total area) in10×40magnification light microscopy; The expression of VEGF were detected by immunohistochemical SP method in specimens. Negative controls with PH7.4PBS instead of the first antibody as a quality control standard.Results1Macroscopic observation, the laser group after treatment than before treatment scar thickness. Laser treatment group after treatment in7,14,30days, the scar proliferation index decreased, compared with the control group decreased significantly.2HE staining was observed in the scar tissue, blood vessels from coarse to fine changes, collagen fibers by malalignment variable order.3Immunohistochemical staining, the levels of VEGF decreased in laser treatment. ConclusionsThe effectiveness of2940nm laser treatment may be related to down-regulation of cytokine VEGF expression which was associated with hypertrophic scar.