芳香维A酸乙酯对银屑病模型大鼠背部皮肤组织恢复的影响及作用机制

Effect of aromatic ethyl retinoic acid on the recovery of back skin tissue in psoriasis model rats and its mechanism

目的探讨芳香维A酸乙酯对银屑病模型大鼠背部皮肤组织恢复的影响及作用机制。方法将20只成年雄性Sprague-Dawley大鼠使用咪喹莫特(IMQ)乳霜涂抹在大鼠剃毛的背部皮肤上诱导银屑病炎症模型,共成功建立模型14只,随机数字表法将其分为2组:银屑病组为银屑病模型大鼠,等量生理盐水灌胃;观察组为银屑病模型大鼠,造模后第3天,10 mg·kg^(-1)·d^(-1)芳香维A酸乙酯灌胃,每组7只。另7只正常大鼠不建模,作为对照组,等量生理盐水灌胃。连续灌胃7 d后处死动物,并进一步分析以用于组织病理学研究和免疫印迹。通过银屑病区域的红斑、结垢和增厚的严重程度指数评估大鼠银屑病的严重程度。通过游标卡尺测量治疗后3、6、9 d的大鼠背部的褶皱厚度。通过蛋白印迹分析大鼠皮肤信号转导和转录激活因子3(STAT3)和角蛋白17(K17)的蛋白表达。通过流式细胞仪分析牛皮癣大鼠脾脏中Th1和Th17细胞的浸润。通过酶联免疫吸附试验检测试剂盒分析大鼠组织中炎症因子肿瘤坏死因子α(TNF-α)、白细胞介素(IL)-1β、IL-6和IL-17A的含量。通过免疫组织化学染色分析大鼠背部组织中增殖细胞核抗原(PCNA)、兜甲蛋白(loricrin)和角蛋白10(K10)的蛋白表达。结果银屑病组较对照组的红斑评分、结垢评分和增厚评分升高(P<0.05),观察组较银屑病组红斑评分、结垢评分和增厚评分降低(P<0.05)。银屑病组较对照组治疗后3、6、9 d的褶皱厚度增多(P<0.05),观察组较银屑病组厚度减少(P<0.05)。银屑病组较对照组STAT3和K17的蛋白表达升高(P<0.05),观察组较银屑病组蛋白表达降低(P<0.05)。银屑病组较对照组Th1和Th17细胞的含量升高(P<0.05),观察组较银屑病组Th1和Th17细胞的含量降低(P<0.05)。银屑病组较对照组TNF-α、IL-1β、IL-6和IL-17A的水平升高(P<0.05),观察组较银屑病组TNF-α、IL-1β、IL-6和IL-17A的水平降低(P<0.05)。银屑病组较对照组PCNA蛋白表达降低(P<0.05),loricrin和K10的蛋白表达升高(P<0.05),观察组较银屑病组PCNA蛋白表达升高(P<0.05),loricrin和K10的蛋白表达降低(P<0.05)。结论芳香维A酸乙酯通过下调STAT3/K17和Th1/Th17级联反应,抑制角质细胞的分化和炎症反应,从而发挥抵抗银屑病作用,并促进背部组织恢复。

Objective To investigate the effect of aromatic ethyl retinoic acid on the recovery of back skin tissue in psoriasis model rats and its mechanism.Methods Twenty adult male Sprague-Dawley rats were applied with imiquimod(IMQ)cream on the shaved back skin of the rats to induce psoriasis inflammation models.A total of 14 models were established and divide them into 2 groups according to the random number table method:psoriasis group(psoriatic model rats,the same amount of normal saline gavage)and observation group(psoriasis model rats,3 days after modeling,10 mg·kg^(-1)·d^(-1) ethyl aromatic tretinoin was intragastrically administered for 7 consecutive days),7 rats in each group.The other 7 normal rats were not modeled and served as a control group,and the same amount of normal saline was given to the stomach.The animals were sacrificed after 7 days of continuous gavage and further analyzed for histopathological studies and immunoblotting.The severity of psoriasis in rats was evaluated by the severity index of erythema,scaling and thickening in the psoriasis area.The thickness of the folds of the rat's back on the 3rd,6th,and 9th day was measured by a vernier caliper.The protein expression of STAT3 and K17 in rat skin was analyzed by Western blotting.The infiltration of Th1 and Th17 cells in the spleen of psoriasis rats was analyzed by flow cytometry.The contents of inflammatory factors TNF-α,IL-1β,IL-6 and IL-17A in mouse tissues were analyzed by ELISA detection kit.The protein expression of PCNA,loricrin and keratin 10(K10)in rat back tissue was analyzed by immunohistochemical staining.Results The erythema score,scaling score,and thickening score in the psoriasis group were higher than those in the control group(P<0.05),and erythema score,scaling score,and thickening score in the observation group were lower than the those in the psoriasis group(P<0.05);Compared with the control group,the thickness of the folds in the psoriasis group was increased on the 3rd,6th and 9th day(P<0.05),and the thickness of the observation group was reduced compared with the psoriasis group(P<0.05).The protein expression of STAT3 and K17 in the psoriasis group was higher than that in the control group(P<0.05),and the protein expression in the observation group was lower than that in the psoriasis group(P<0.05).The content of Th1 and Th17 cells in the psoriasis group was higher than that in the control group(P<0.05),and the content of Th1 and Th17 cells in the observation group was lower than that in the psoriasis group(P<0.05).The levels of TNF-α,IL-1β,IL-6 and IL-17A in the psoriasis group were higher than those in the control group(P<0.05),and levels of TNF-α,IL-1β,IL-6 and IL-17A in the observation group were lower than those in the psoriasis group(P<0.05).The expression of PCNA protein in the psoriasis group was lower than that in the control group(P<0.05),and the protein expression of loricrin and K10 was higher than that in the control group(P<0.05),the expression of PCNA protein in the observation group was higher than that in the psoriasis group(P<0.05),the expression of loricrin and K10 protein was lower than that in the psoriasis group(P<0.05).Conclusion Ethyl aromatic tretinoin can down-regulate the cascade of STAT3/K17 and Th1/Th17,inhibit the differentiation and inflammatory response of keratinocytes,thereby playing a role in resisting psoriasis and promoting back tissue recovery.