慢性瘙痒通常指瘙痒持续时间超过6周以上。慢性瘙痒因其长期存在给患者生理、心理带来严重影响。引起慢性瘙痒的因素很多，皮肤干燥症、一些炎症性皮肤病和系统性疾病都可能引起或伴发慢性瘙痒。皮肤屏障功能受损可造成皮肤干燥、瘙痒，而角质层及其细胞中丝聚蛋白（filaggrin，FLG）是维持正常皮肤屏障功能的重要因素之一。慢性瘙痒常为非组胺源性瘙痒，神经生长因子（nerve growth factor，NGF）、组织蛋白酶S（cathepsin S，CTSS）和胸腺基质淋巴细胞生成素（thymic stromal lymphopoietin，TSLP）及其受体在这类瘙痒中可能起重要作用。另一方面，炎症性皮肤病的发生、发展中与皮肤屏障功能受损存在一定关系，皮肤屏障功能受损造成皮肤干燥、皮肤稳态失衡，形成局部炎症微环境，同时表皮炎症也会削弱皮肤屏障功能。NLRP3（NOD-like receptor family pyrin domain containing 3，NOD样受体蛋白3）炎症小体及其介导的炎症反应参与了炎症性皮肤病的发生和发展，它的激活促进下游途径中白介素-1β（interleukin-1beta，IL-1β）和肿瘤坏死因子-α（tumor necrosis factor-alpha，TNF-α）等经典促炎症因子的释放，且NLRP3炎症体以及IL-1β等的高表达可降低FLG-2蛋白的表达。因此，皮肤屏障功能、皮肤炎症微环境和慢性瘙痒三者之间存在的联系是值得研究的一个问题。

针对与皮肤干燥和皮肤屏障功能受损有关的瘙痒，目前还没有特别有效的方法。是否可以通过修复受损的皮肤屏障功能、改善局部皮肤区域的炎症微环境来缓解由干燥皮肤引发的瘙痒，改善这类患者的生活质量，一直是值得关注的问题。

β-葡聚糖具有维持皮肤免疫系统平衡、抗氧化和缓解炎症等多种生物活性，在护肤品方面的应用受到关注。泛醇系原维生素B5，进入体内转化成泛酸（维生素B5）后参与包括表皮细胞间脂质合成和脂肪酸的降解等各种生理过程。泛醇本身亦具有保湿和加强皮肤屏障功能的作用。β-葡聚糖和泛醇局部应用是否对于皮肤干燥、皮肤屏障功能受损、炎症微环境引起的慢性瘙痒具有减缓作用，有待于探讨。

本研究的第一部分通过分别建立丙酮-乙醚-水（Acetone-ether-water，AEW）诱导的小鼠慢性瘙痒模型和2,4-二硝基氯苯（2,4-dinitrochlorobenzene，DNCB）诱发的小鼠慢性湿疹样模型，初步探究皮肤屏障、炎症、瘙痒三者之间的相关联系。研究的第二部分，通过建立的AEW小鼠慢性瘙痒模型，观察局部应用含β-葡聚糖和泛醇的喷雾剂后对皮肤屏障功能的修复、缓解瘙痒行为，以及皮肤局部炎症状态的改善效果，为探索一种减轻瘙痒的补充和替代医学治疗手段提供实验依据。

第一部分 小鼠AEW慢性瘙痒模型及DNCB诱导的慢性湿疹样模型中皮肤屏障功能、炎症、瘙痒状况的同步观察

目的：同步观察小鼠AEW慢性瘙痒模型及DNCB慢性湿疹样模型中皮肤屏障、炎症及瘙痒状况。

方法：通过颈背部皮肤涂抹丙酮/乙醚溶液和水(AEW)或二硝基氯苯（DNCB）致敏及激发的方法分别制备小鼠干性皮肤慢性瘙痒模型及小鼠慢性湿疹样模型；通过视频录像来统计瘙痒行为学；通过皮肤水分流失测试仪TM300 测量小鼠TEWL；通过组织病理学检查皮损组织学改变，实时荧光定量PCR检测各组小鼠FLG、炎症相关分子（NLRP3，ASC，caspase-1，IL-1β，TNF-α）以及瘙痒相关分子及受体（CTSS、NGF、TSLP及PAR2、MrgprC11、TSLPR）的表达。

结果：与正常对照组相比，AEW及DNCB小鼠模型TEWL显著升高，同时FLG表达显著降低（P < 0.001）；模型小鼠皮损中5种炎症相关分子mRNA表达显著升高（P < 0.05）；AEW及DNCB小鼠模型自发搔抓次数、三个瘙痒相关分子及三种受体mRNA表达出现不同程度的升高（P < 0.05）。

结论：AEW慢性瘙痒模型及DNCB慢性湿疹样模型皮损中受损的皮肤屏障功能、炎症及瘙痒的共存状态提示其存在错综复杂的联系。

第二部分 含β-葡聚糖和泛醇的喷雾剂对小鼠AEW模型修复皮肤屏障、缓解炎症及瘙痒的作用

目的：探索含β-葡聚糖和泛醇的喷雾剂是否能修复小鼠AEW模型的屏障损伤、缓解皮肤炎症及瘙痒，为探索一种减轻瘙痒的补充和替代医学（CAM）治疗手段提供实验依据。

方法：使用颈背部皮肤涂抹丙酮/乙醚溶液和水(AEW)的方法制备小鼠干性皮肤慢性瘙痒模型；通过视频录像来统计瘙痒行为学；通过皮肤水分流失测试仪TM300 测量小鼠TEWL；使用H&E染色检查造模部位组织病理学；通过实时荧光定量PCR检测各组小鼠FLG、炎症相关分子（NLRP3，ASC，caspase-1，IL-1β，TNF-α）以及瘙痒相关分子及受体（CTSS、NGF、TSLP及PAR2、MrgprC11、TSLPR）的表达；通过Western blot检测小鼠皮损处NLRP3蛋白的表达。

结果：使用含有β-葡聚糖和泛醇的喷雾剂可明显缓解AEW处理引发的小鼠的自发性抓挠，抓挠次数相较模型组明显下降（P < 0.001）；一定程度上修复了破坏的皮肤屏障， TEWL值明显下降，FLG表达明显升高（P < 0.01）；它还明显降低了AEW处理造成的炎症分子（NLRP3、ASC、caspase-1、IL-1β、TNF-α） mRNA表达的升高（P < 0.01）；降低了小鼠皮肤中的瘙痒分子（CTSS、NGF、TSLP）及瘙痒相关受体（PAR2、MrgprC11、TSLPR）mRNA表达水平（P < 0.001）。

结论：β-葡聚糖和泛醇的局部应用有效地减轻了AEW小鼠慢性瘙痒模型的皮肤屏障功能损伤、皮肤炎症以及瘙痒严重程度，有望成为缓解慢性瘙痒的有效CAM疗法，值得深入探讨。

Itch lasts for more than 6 weeks is called chronic pruritus, which has serious physical and psychological effects on the patient due to its long-term presence. Dry skin, inflammatory skin diseases and systemic diseases may cause or accompany chronic itching. Impaired skin barrier function can cause dry, itchy skin, and stratum corneum (SC) containing filaggrin (FLG) is important for maintaining normal skin barrier function. Chronic pruritus is usually histamine-independent and nerve growth factor (NGF), cathepsin S (CTSS) and thymic stromal lymphopoietin (TSLP) and their receptors may play an important role in this type of pruritus. There is a relationship between the onset or development of inflammatory skin diseases and impaired skin barrier function, which causes dry skin and imbalance in skin homeostasis, resulting in a local inflammatory microenvironment. Epidermal inflammation also weakens skin barrier function in turn. NLRP3 (NOD-like receptor protein 3) inflammasome mediated inflammatory responses are involved in the onset and development of inflammatory skin diseases. Activation of NLRP3 inflammasome promotes the release of pro-inflammatory factors such as IL-1β and TNF-α. High expression of NLRP3 inflammasome and IL-1β decreases the expression of FLG-2. Therefore, it is worthwhile to investigate the link between skin barrier function, skin inflammatory microenvironment and chronic pruritus.

No particularly effective methods are available for pruritus associated with dry skin and impaired skin barrier function. Whether pruritus triggered by dry skin can be relieved by repairing the damaged skin barrier and improving the inflammatory microenvironment in the local skin area to improve the quality of life of patients. This has been a matter of concern.

β-glucan has various biological activities such as maintaining the balance of skin immune system, antioxidant and alleviating inflammation, and has received attention in skin care applications. Panthenol, also known as pro-vitamin B5, is converted into pantothenic acid (vitamin B5) in the body and is involved in various physiological processes including lipid synthesis and fatty acid metabolism in epidermal cells. Panthenol also has moisturizing and skin barrier function strengthening effects. Panthenol also has moisturizing and skin barrier function strengthening effects. Whether topical application of β-glucan and panthenol has a mitigating effect on chronic pruritus caused by dry skin, impaired skin barrier function, and inflammatory microenvironment remains to be explored.

In the first part of this study, the status of skin barrier function, inflammation and pruritus were observed by establishing acetone-ether-water (AEW) chronic pruritus model and 2,4-dinitrochlorobenzene (DNCB) chronic eczema-like model. In the second part of the study, the effects of β-glucan and panthenol on skin barrier function, topical skin inflammation, and pruritus were observed via the AEW mouse model of chronic pruritus, so as to provide an experimental basis for exploring a complementary and alternative medical (CAM) treatment to alleviate pruritus.

Part Ⅰ. Simultaneous observation of skin barrier function, inflammation, and pruritic conditions in the AEW chronic pruritus model and DNCB chronic eczema-like model

Objective: Simultaneously observe the skin barrier, inflammation and pruritic conditions in the mouse AEW chronic itch model and DNCB chronic eczema-like model.

Methods: A mouse chronic itch model and a mouse chronic eczema-like model were prepared by applying acetone/ether solution and water or DNCB in the skin, respectively; pruritic behavior was observed by videotaping; transepidermal water loss (TEWL)was measured by TM300; expression of FLG, inflammation-related molecules (NLRP3, ASC, caspase-1, IL-1β, TNF-α) and pruritus-related molecules and receptors (CTSS, NGF, TSLP and PAR2, MrgprC11, TSLPR) were measured by real-time quantitative PCR.

Results: Compared with normal controls, TEWL was significantly higher in AEW and DNCB mouse models, while FLG expression was significantly lower (P < 0.001); mRNA expression of five inflammation-related molecules was significantly higher in the skin lesions of model mice (P < 0.05); mRNA expression of the number of spontaneous scratching, three pruritus-related molecules and three receptors appeared to be differentially higher in AEW and DNCB mouse models (P < 0.05).

Conclusion: The coexistence of impaired skin barrier function, inflammation and pruritus in the lesions of the AEW chronic itch model and the DNCB chronic eczema-like model suggests an intricate association between them.

Part II. Effects of sprays containing β-glucan and panthenol on repairing skin barrier, alleviating inflammation and pruritus in an AEW-induced mouse model

Objective: To explore whether sprays containing β-glucan and panthenol can alleviate skin barrier damage, inflammation and pruritus in the AEW mouse model and provide an experimental basis for the development of complementary and alternative medicine (CAM) treatments to reduce pruritus.

Methods: A mouse chronic itch model was prepared by applying acetone/ether solution and water in the skin; itch behavior was measured by videotaping; TEWL was measured by TM300; histopathology of the modeling site was examined using H&E staining; expression of FLG, inflammation-related molecules (NLRP3, ASC, caspase-1, IL-1β, TNF-α) and pruritus-related molecules and receptors (CTSS, NGF, TSLP and PAR2, MrgprC11, TSLPR) was measured by real-time quantitative PCR; expression of NLRP3 protein in skin lesions was detected by Western blot.

Results: The use of the spray containing β-glucan and panthenol significantly alleviated the spontaneous scratching triggered by AEW treatment in mice(P < 0.001); it repaired the damaged skin barrier to some extent, with a significant decrease in TEWL values and a significant increase in FLG expression (P < 0.01); it also significantly reduced the high expression of inflammatory molecules (NLRP3, ASC, caspase-1, IL-1β, TNF-α) caused by AEW treatment (P < 0.01); and reduced the mRNA expression levels of pruritic molecules (CTSS, NGF, TSLP) and pruritus-related receptors (PAR2, MrgprC11, TSLPR) in mouse skin lesion (P < 0.001).

Conclusion: The topical application of β-glucan and panthenol effectively reduced skin barrier dysfunction, skin inflammation, and pruritus severity in the AEW mouse model of chronic pruritus, and is expected to be an effective CAM therapy for relieving chronic itch that deserves in-depth investigation.