有氧和抗阻运动经IL-18/IL-18R通路对SAMP8小鼠抗皮肤老化的作用研究

Anti-skin aging effects of aerobic and resistance exercise via IL-18/IL-18R pathway in SAMP8 mice

目的:探讨有氧和抗阻运动经白细胞介素18(IL-18)/IL-18受体(IL-18R)通路对SAMP8小鼠皮肤老化的影响,为运动抗皮肤老化以及防治慢性炎症性皮肤相关疾病提供新思路。方法:健康雄性28周龄快速老化SAMP8小鼠24只,随机分为模型组、有氧运动组和抗阻运动组,每组8只,另设8只同龄抗快速老化SAMR1小鼠作为对照组。有氧运动组采用匀速水平运动跑台训练8周(每天1次,每周5次),模型组采用递增负重爬梯训练8周(隔天1次,每周3次)。HE染色观察皮肤表皮、真皮结构改变;间苯二酚碱性品红染色观察皮肤弹力纤维的变化;免疫组织化学观测皮肤衰老标志物P16和P21的表达;ELISA法检测血清和皮肤炎症指标IL-18、IL-1β和肿瘤坏死因子α(TNF-α)含量及皮肤IL-18R和IL-18结合蛋白(IL-18BP)含量;免疫荧光法双染IL-18和IL-18R;RT-qPCR检测IL-18和IL-18R的mRNA表达水平。结果:与对照组相比,模型组小鼠表现出明显的衰老体征,HE染色可见皮肤纹理粗糙,皮肤变薄等;间苯二酚染色可见弹力纤维排列紊乱,出现分离、增粗变短、扭曲断裂现象;皮肤表皮层和真皮层中P16和P21蛋白表达升高(P<0.01);血清和皮肤IL-1β、TNF-α和IL-18含量显著升高,皮肤IL-18R含量显著升高,IL-18BP含量显著降低(P<0.05或P<0.01);IL-18与IL-18R存在共定位现象;皮肤IL-18和IL-18R的mRNA表达量均显著升高(P<0.01)。与模型组相比,有氧运动和抗阻运动组皮肤外观明显改善;表皮厚度均显著增加(P<0.05或P<0.01),抗阻运动组真皮厚度显著增加(P<0.05);弹力纤维排列较整齐有序;有氧运动组皮肤P16蛋白表达降低(P<0.05);有氧运动组血清TNF-α含量、血清和皮肤IL-18含量显著降低(P<0.05),抗阻运动组血清和皮肤IL-1β、TNF-α和IL-18含量显著降低(P<0.05或P<0.01);有氧运动组和抗阻运动组皮肤IL-18R含量均显著降低(P<0.01),IL-18BP含量均显著升高(P<0.01),IL-18与IL-18R共定位表达均显著降低;IL-18和IL-18R的mRNA表达量均显著降低(P<0.01)。结论:有氧运动和抗阻运动均能延缓快速衰老小鼠的增龄性皮肤老化,运动下调的IL-18/IL-18R信号通路可能是其作用途径。

AIM:To investigate the effects of aerobic and anti-resistance exercise on skin aging in SAMP8 mice via interleukin-18(IL-18)/IL-18 receptor(IL-18R)pathway and provide new concepts for anti-skin aging and prevention and treatment of chronic inflammatory skin-related diseases.METHODS:Twenty-four healthy male 28-week-old rapidly aging SAMP8 mice were randomly divided into model group,aerobic exercise group,and resistance exercise group,with 8 mice in each group.Eight same-aged rapidly aging SAMR1 mice were used as control group.The mice in aerobic exercise group underwent running table training at a constant speed(1 time per day,5 times per week)for 8 weeks,and those in model group underwent incremental weight-bearing ladder training for 8 weeks(1 time every other day,3 times per week).The HE staining was performed to observe the structural changes of the epidermis and dermis,and Weigert staining was conducted to observe the changes in skin elastic fibers.Immunohistochemistry was performed to observe the expression of skin aging markers P16 and P21.The ELISA was used to detect the concentrations of serum and skin inflammatory factors IL-18,IL-1β and tumor necrosis factor-α(TNF-α)and the levels of dermal IL-18R and IL-18 binding protein(IL-18BP).Double immunofluorescence staining of IL-18 and IL-18R was conducted.The RT-qPCR was used to detect the mRNA expression levels of IL-18 and IL-18R.RESULTS:Compared with control group,the mice in model group exhibited obvious signs of aging.The results of HE staining revealed indications such as rough skin texture and skin thinning.Weigert staining revealed the following:the elastic fibers were disordered,separated,thickened,shortened,twisted,and broken.The expression levels of P16 and P21 proteins in the epidermis and dermis were elevated(P<0.01).Serum and skin IL-1β,TNF-α and IL-18 levels were significantly higher.Skin IL-18R content was significantly higher,and IL-18BP content was significantly lower(P<0.05 or P<0.01).Colocalization phenomenon existed between IL-18 and IL-18R.Skin IL-18 and IL-18R mRNA expression levels were significantly higher(P<0.01).Compared with model group,the skin appearance of the aerobic exercise and resistance exercise groups was significantly improved(P<0.05 or P<0.01).The thickness of the epidermis(P<0.05)and dermis increased significantly in resistance exercise group(P<0.01),and the elastic fibers were arranged in a more neat and orderly manner.The expression of P16 protein in the skin was decreased in aerobic exercise group(P<0.05).The levels of serum TNF-α,and serum and skin IL-18 were decreased in aerobic exercise group(P<0.05).The levels of serum and skin IL-1β,TNF-α and IL-18 in the resistance exercise group were decreased(P<0.05 or P<0.01).Skin IL-18R content was significantly decreased in both aerobic and resistance exercise groups(P<0.01).IL-18BP content was significantly increased(P<0.01),and colocalized expression levels of IL-18 and IL-18R were significantly decreased.The mRNA expression of IL-18 and IL-18R was significantly decreased in both aerobic and resistance exercise groups(P<0.01).CONCLUSION:Both aerobic and resistance exercise delay age-increased skin aging in rapidly aging mice,and the IL-18/IL-18R signaling pathway down-regulated by exercise may be the pathway of this effect.