皮肤光老化SD大鼠模型的构建及评价标准的探讨

Etablishment and evaluation standards of skin photoaging model in SD rat

目的:建立实用、有效的皮肤光老化Sprague-Dawley大鼠模型,并探讨该疾病模型的评价标准。方法:SD大鼠随机分为实验组和对照组,每组8只。采用长波紫外线结合中波紫外线模拟日光照射实验组大鼠背部皮肤,每天一次,照射总剂量递增,持续10周。光照结束后,观察皮肤外观、组织病理、超微结构及生化改变。结果:10周结束后,实验组大鼠较对照组皮肤粗糙、缺乏弹性、出现明显深大皱纹。表皮增厚、腺体明显增生、胶原纤维减少,超微结构下可见老化坏死细胞增多;对皮肤组织进行检测,实验组丙二醛含量升高[(10.43±5.67)nmol/mgprot,P=0.009]、羟脯氨酸减少[(7.37±1.15)μg/mg,P=0.010]较对照组有统计学差异,而超氧化物歧化酶的活性[(21.09±8.60)U/mgprot,P=0.401]改变无统计学差异。结论:实验组SD大鼠皮肤具备光老化的典型特征,表明利用紫外线剂量递增、维持10周的方法可成功构建皮肤光老化动物模型,并为评价皮肤光老化程度提供了全面系统的技术参数。

Objective：To establish practical and efficient skin photoaging model in Sprague-Dawley（SD）rat and to investigate the evaluation standards. Methods：The SD rats were randomly divided into normal control group and model group,8 rats in each group.The dorsal skin of rats in model group was irradiated with increasing doses of simulated solar light combined ultraviolet-A and ultraviolet-B everyday for 10 weeks. After irradiation,visible changes,histological and ultrastructural features,biochemical indicators were detected. Results：After 10 weeks＇ irradiation,the animal skin of model group became coarse and lack of elasticity. Visible deep wrinkles were observed. The wrinkle grading scale indicated the development of wrinkling. Histological alterations included epidermis thickening,hyperplasia of glands,elastosis and loss of collagen. Meanwhile,increasing number of senescent and apoptotic cells and structure destruction of dermis were seen in ultrastructure. Compared with those of the control group, there was a statistical significant increase in the content of MDA[（10.43 ± 5.67）nmol/mgprot,P=0.009],a decrease in the content of Hyp [（7.37 ± 1.15）μg/mg,P=0.010] in skin tissue of model group,while SOD activity had no obvious difference[（21.09 ± 8.60）U/mgprot,P=0.401]. Conclusion：These typical features demonstrate the successful establishment of skin photoaging model in SD rat. Moreover,it provides comprehensive and systematic evaluation standards for photoaged skin.