| Objective:To explore the effect and mechanisms that use of IPL treat hypertrophic scars of rabbit ear.Methods: 30 New Zealand white rabbits were selected, two same hypertrophic scar models were made in the ventral surface of the rabbits'ears, two wounds in each ear.Then the rabbits were divided into two groups randomly: the treatment group and the control group. The treatment groups were treated by IPL at the 3th, 5th, 7th week after operation. The control groups were untreated. Morphological appearances of the hypertrophic scar were observed, and samples of scar tissues were collected for HE dyeing and immunohistochemistry detection for the expression of VEGF (vascular endothelial growth factor),PCNA(proliferating cell nuclear antigen )andα-SMA, microvessel density was calculated by the expression ofα-SMA at the 3rd, 5th, 7th, 9th week after operation. Two normal rabbits were fed for 9 weeks with no intervention, ventral surface skin of the rabbits'ears were collected to undergo the same examination as related frontly,the left rabbits were fed continuously until the scars became soften and flat completely.Results:1,General observation: Scar epithelialization occurred within 18 to 20 days after operation.About three weeks after epithelialization,the scars'height was three times thicker than the skin. In the control group ,the scars began to degenerate and soften and the color became weak gradually 7 weeks later after the operation. Comparing with the control group,the height of scars reduced significantly in the IPL treatment group.The scars became soften and completely flat 65.75±5.99 days later in the IPL treatment group, while in the control goup, 96.50±8.59 days were needed.2,The HE dyeing: 3 weeks after operation, the control group has more fibroblasts and capillaries in scar tissues.5 weeks after operation , the fibroblasts and vascular distribution was rich in scar tissues, collagen fiber was bulky and arranged disorderly. 7 weeks after operation, the number of fibroblasts and capillary in scar tissues reduced.9 weeks after operation, fibroblasts and capillaries were still relatively rich in the scar tissues. After IPL treatment,the fibroblasts gradually decreased.3,The expression of MVD :In the treatment group: the total expression level of MVD-positive particles in scar tissues 3 weeks after operation was significantly higher than that in 5 weeks,the level of expression of MVD-positive particles in 5 weeks after operation was higher than that in 7 weeks, the level of expression of MVD-positive particles in 7 weeks after operation was higher than that in 9 weeks, There was no significant difference between the levels of MVD expression in scar tissues 9 weeks after operation and normal skin(P>0.05). In the control group: the level of MVD expression in scar tissues 5 weeks after operation was higher than that in 3 weeks after operation .The other changing trends were consistent with the treatment group. Comparing with the control group,the level of MVD expression in the treatment group was significantly decreased over the same period (P<0.05).4,The expression of VEGF: In the treatment group: 3 weeks after operation,the VEGF-positive dyeing granules could be observed in the cytoplasm, the total expression level was significantly higher than that in 5 weeks after operation, the expression of VEGF-positive dyeing granules in scar tissues 5 weeks after operation was higher than that in 7 weeks, the expression of VEGF-positive dyeing granules in 7 weeks after operation was higher than that in 9 weeks. There was no significant difference between the levels of VEGF expression in scar tissues 9 weeks after operation and normal skin(P>0.05). In the control group: the level of VEGF expression of positive particles in scar tissues 5 weeks after operation was higher than that in 3 weeks after operation.The other changing trends were consistent with the treatment group. Comparing with the control group,the level of MVD expression in the treatment group was significantly decreased over the same period (P<0.05).5,The expression of PCNA: In the treatment group: 3 weeks after operation, the PCNA-positive dyeing granules could be observed in the nucleus, the total expression level was significantly less than that in 5 weeks after operation, the level of PCNA expression of positive particles in scar tissues 5 weeks after operation was higher than that in 7 weeks, the level of PCNA expression in scar tissues 7 weeks after operation was higher than that in 9 weeks, the difference of PCNA expression levels in scar tissues between 9 weeks after operation group and normal skin group was not statistically significant (P>0.05). In the control group: the level of PCNA expression in scar tissues 5 weeks after operation was higher than that in 3 weeks.The other changing trends were consistent with the treatment group. Comparing with the control group,the level of PCNA expression in the treatment group was significantly decreased over the same period (P<0.05).Conclusions:1.It is effective method that treat the hypertrophic scar of rabbit ear with IPL.2.IPL may prevent and treat the hypertrophic scars through destroying the microvessel and restraining the formation of newly born capillaries . |
