| Nonablative skin rejuvenation, as a kind of new treatment applied to preventing and curing skin aging in the clinic has been accepted by patients recently due to its effects of free-injury, high-efficacy and rapid recovery. Thus, it has a great promising future. Some research observed the becoming thicker of collagen granz, increased expression of type I procollagens protein and its mRNA level as well as the increased content of hydroxyproline after nonablative skin rejuvenation. However, the mechanism has not been unravelled. It is traditionally viewed that nonablative skin rejuvenation can induce blood vessels to release cytokines which stimulate fibroblasts to synthesize collagen through inflammations during and after photodamaging.As we all know, collagen fibers are synthesized by fibroblasts , bFGF and TGF-β are the main cytokines inducing fibroblasts to proliferate- Some research has indicated that the expression of bFGF and TGF-β increased in the open injury, which play an important role in the process of healing of skin wounds.But no reports focused on the role of fibroblasts and those cytokines in the process of nonablative skin rejuvenation. We used the Kunming mice as subjects and divided them into three groups (A, B, C), each included six ones. A, B, C groups were irradiated with 1320nm cooltouch laser(20J/cm~2)in the skin of left back;B, C groups were irradiated two and three times respectively ;the skin of right back of A, B, C groups was adopted as control. The expression of bFGF and TGF-B 1 in the mouse skin was examined by the immunohistochemistry. The fibroblasts were isolated from the foreskin and cultured. When cell count reaching 1.4×10~5/ml and cell viability reaching ninety percent, we seeded fibroblasts in each well of a 24-well plate. One group is a control and other three ones are low, intermediate and high energetic groups respectively. The fibroblasts were irradiated by laser with 15J/cm~2, 20J/cm~2 and 24J/cm~2 energy for three times. We examined the levels of bFGF and TGF- β 1 by ELISA in 0, 24, 48 and 72 hours and explored therole of bFGF and TGF-β 1 in the process of nonablative skin rejuvenation by comparing the differences of bFGF and TGF-β 1 expression in vivo and vitro, then understand the influence 1320 cooltouch laser can have on the fibroblasts proliferation by accounting the changes in the number of fibroblasts after being irradiated.According to our research on immunohistochemistry result, there are significant differences in the expression of bFGF and TGF-β 1 between the group irradiated by three times and others (p<0.01). The number of fibroblasts get increased after being irradiated by the energy of 20J/cm2 (P<0.05)compared with the contrasted group. The ELISA result indicates that the secretion of bFGF increased in the group of intermediate and high energetic level after laser irradiating and may reach the peak at 24 hours. It is apprently different from the control group(P<0.01), while the amount of TGF-β 1 secretion seems to get decreased in each group at all energetic levels, which means that the more energy, the more obviously the amount of secretion will fall, and at 24 hours it can reach the top level as well. Comparing another 2 groups with the control, we can find out more crystal differences (P<0.05) which mean there are significant differences. The research implied that the directinfluence of laser on the fibroblasts is to promote secretion of bFGF and to inhibit secretion of TGF-β 1, while its influence on the tissue is to promote the secretions of the both. Nonablative skin rejuvenation not only can induce fibroblasts to secrete more bFGF but also induce the blood vessels to release cytokines which stimulate endothelial cell to express more of bFGF and TGF-β 1. Furthermore, fibroblastic proliferation can accelerate once being irradiated by laser. The effects of laser treatment with 1320nm cool touch laser have close correlation with the energy and the times of treatment. The energic level of 20J/cm~2 and the term of more than 3 times are proper relatively.
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