The Effects Of Melatonin On The Hypertrophic Scars In Animal Model

Objective:To study on the effect of melatonin in animal models of hypertrophic scar. Methods:1 、 Build the rabbits’ ears scar models, and set the experimental group and control group. The experimental group daily intraperitoneal injection of melatonin 5mg/kg(each animal was injected melatonin solution 10ml);the control group with intraperitoneal injection amount of saline everyday. Injection time was about 8 pm. Feeding after 6 weeks, photograph and collection of scar tissue, fixed specimens.2、Record the wound healing time, observ the wound edema、hemorrhage and the amount of secretions, assessment of inflammatory reaction degree; according to thickness、color、hardness, the evaluation of the scar hyperplasia.3、Using HE staining after taking photos, with Image- Pro Plus6.0 software measuring the thickness of the scar, analysis of the experimental group and control group differences.4、Using Sirius red staining and Masson staining after taking photos, with Image- Pro Plus6.0 software measurement of collagen area percentage,analysis of the experimental group and control group differences.5、Using immunohistochemical method after taking photos, with Image- Pro Plus6.0 software measurement of collagen area percentage,analysis of the experimental group and control group differences.6、Using Western-blot analysis of Effect of melatonin about TGF-β1 protein secretion. Result:Results showed that the experimental group wound secretion reduces in the third day, the swelling subsided; the control group secretion was still a lot of, edema had not faded completely. The experimental group scab skin had fall off and wound healing in the 19 days. The control group cab skin had fall off and wound healing in the 23 days. The experimental scar hyperplasia was significantly lower than the control group in the 42 days. The experimental group Scar tissue thickness was 920.30±227.56μm, the control’s thickness was 1033.10±263.59μm, the experimental group of scar hyperplasia degree was lower than the control group(P < 0.05). The experimental groupⅠ type collagen content was 0.115±0.051%, the control group was 0.148±0.043%. The experimental group Ⅲ type collagen content was 0.145±0.041%, the control group was 0.121±0.034%. The control group Ⅰ collagen type content was higher than the experimental group(P < 0.05), The experimental group Ⅲ collagen type content was higher than the control group(P < 0.05). The experimental group α-SMA content was 0.136±0.014%, the control group α-SMA content was 0.255±0.015%. The control group α-SMA content was higher than the experimental group(P < 0.05). The experimental group TGF-β1 content was 0.310±0.06, the control group was 0.650±0.04. The experimental group TGF-β1 content was lower than the control group(P < 0.05). Conclusion:The experimental results show: melatonin can promote wound healing, adjusting the proportion of collagen type Ⅲ、Ⅰ, inhibition the content of TGF-β1, inhibition of fibroblast to myofibroblast transformation, prevent scar hyperplasia. The melatonin can reduce scar hyperplasia.