Influence of different types of contact hypersensitivity on imiquimod-induced psoriasis-like inflammation in mice

Abstract

It is currently believed that psoriasis and allergic contact dermatitis (ACD) are different diseases; however, they share clinical similarities. The involvement of T helper 17 (Th17) cells in these disorders provides a novel opportunity to investigate the relationship between them. The present study aimed to determine whether the same or overlapping inflammatory pathways are involved in the two diseases, and the influence of different types of ACD on psoriasis. Compound mouse models of Th1 or Th2-type contact hyper-sensitivity (CHS) combined with imiquimod (IMQ)-induced psoriasis-like inflammation were established, in order to mimic the characteristics of ACD and psoriasis. Histopathology, immunohistochemistry and cytokine detection in blood serum and tissues were used to compare the differences between the mice treated with IMQ alone or IMQ combined with Th1 and Th2-type CHS. As compared with the IMQ-treated mice or IMQ-treated Th1-type CHS mice, the mice with Th2-type CHS treated with IMQ exhibited more serious psoriasis-like inflammation with increased epidermal thickness and infiltrating cells in the derma. High mRNA expression levels of interleukin (IL)-17, IL-22, IL-23, TNF-α and RORγt were detected in back skin lesions. Additionally, high levels of IL-17 and IL-22 in blood serum were detected in IMQ-treated mice combined with Th2-type CHS. The mice treated with IMQ alone, and IMQ treatment combined with Th1-type CHS had a comparable psoriasis-like inflammatory response in the back skin. In conclusion, these data demonstrate that Th2-type CHS exacerbated the IMQ-treated psoriatic inflammation of mice via the IL-23/IL-17 axis. Th17 cells and associated pathways may link ACD and psoriasis. Therefore, patients with psoriasis should avoid contact with specific sensitizers, such as fragrance and rubber products, which may induce Th2 polarization.

Probiotic Lactobacillus sakei proBio-65 Extract Ameliorates the Severity of Imiquimod Induced Psoriasis-Like Skin Inflammation in a Mouse Model

“…All trimmed ear and dorsal skin tissues were re-fixed in 10% neutral buffered formalin (NBF), again for 24 h. After paraffin embedding, 3–4 μm sections were prepared. Representative sections were stained with hematoxylin and eosin (HE) for general histological architectures or Masson’s trichrome (MT) for collagen fibers in the dermis of the ear and dorsal back skin tissues ( Kim et al, 2015a ; Bai et al, 2016 ). The histological profiles of individual cross trimmed ear and dorsal skin tissues were observed under a light microscope (Model Eclipse 80 i , Nikon, Tokyo, Japan).…”

“…The histopathological analysis was done by the histopathologist who was unaware of group distribution. To observe more detailed changes, mean total and epithelial thicknesses of ear and dorsal skin tissues (μm), mean numbers of inflammatory cells infiltrated in dermis of ear and dorsal skin tissues (cells/mm 2 of dermis) and mean collagen fiber occupied regions in dermis of ear and dorsal skin tissues (%/mm 2 of dermis) were calculated using a computer-based automated image analyzer ( i Solution FL ver 9.1, IMT i -solution Inc., Vancouver, QC, Canada) according to our previously established methods ( Qin et al, 2014 ; Kim et al, 2015b ; Bai et al, 2016 ). At least five repeated measurements were considered to calculate each mean histomorphometric value, whenever possible, in this histopathological evaluation.…”

“…In addition, IL-19 and IL-17 are known to induce other interleukins which contributes to the psoriasis typical epidermal alterations. Topical application of IMQ, a TLR7/8 ligand and potent immune activator, can induce and exacerbate psoriasis, a chronic inflammatory skin disorder ( van der Fits et al, 2009 ), and has been used as activator for valuable psoriasis animal model ( Qin et al, 2014 ; Bai et al, 2016 ). Additionally, psoriasis may be linked with genuine comorbidities, for example, metabolic disorder and cardiovascular sickness, likely mirroring a systemic provocative part of the infection ( Perera et al, 2012 ).…”

Efeitos do óleo da semente do maracujá na psorí­ase experimental

“…Todos os animais foram submetidos à eutanásia com 25 dias após o início do tratamento, período suficiente para o aparecimento de lesões inflamatórias, tão como escamas, nos animais tratados com Imiquimode (BAI, et al, 2016).…”

“…É um marcador de proliferação específico validado resistente à fixação, portanto, é possível a coloração de tecido em parafina sem restrições(THEILE;MUELLER, 1996). Também conhecido por mostrar expressão aumentada em hiperplasias endometriais e carcinomas(AMALINEI, et al, 2011), se assemelhar a psoríase humana em três dias a seguir à aplicação Imiquimode(BAI, et al, 2016) e para tratar essas lesões desenvolvidas pelo modelo experimental, tratamentos tópicos de baixo custo e à base de produtos naturais como o óleo extraído da semente do maracujá, vem ganhando notoriedade no campo da pesquisa.…”