Establishment of incontinence-associated dermatitis rat models and assessment of the therapeutic effects of zinc oxide, painless skin protective film and silicone dressing

The aim of the present study was to construct incontinence-associated dermatitis (IAD) rat models and observe the therapeutic effects of zinc oxide, painless skin protective film and silicone dressing on IAD. A total of 54 rats were randomly divided into nine groups: i) Control group; ii) trypsin model group; iii) model + zinc oxide group; iv) model + painless skin protective film group; v) model + silicon dressing group; vi) synthetic urine combined with trypsin model group (joint model group); vii) joint model + zinc oxide group; viii) joint model + painless skin protective film group; and ix) joint model + silicone dressing group. A total of 4 days after applying the zinc oxide, protective film or silicon dressing intervention, IAD scores and pH values in skin tissues were examined. Skin tissues and blood samples were collected. Hematoxylin and eosin staining, immunohistochemical staining of major histocompatibility complex class II (MHC-II) and western blot analysis of MHC-II, NF-κB/p65, phosphorylated (p)-NF-κB/p65, STAT1 and p-STAT1 were carried out in skin tissue. Serum IFN-γ, IL-1β, IL-2 and TNF-α levels were determined using ELISA. The results demonstrated that IAD scores and pH values were both higher in the model groups than the control, which were significantly ameliorated by silicone dressing. The skin tissue structure of IAD rats both in trypsin model group and joint model group was severely damaged, the wounds were not covered by epidermis, and numerous inflammatory cell infiltrations were observed. After treatment, dermatitis was improved. Skin tissue from the trypsin and joint IAD models had higher MHC-II, NF-κB p65, p-NF-κB p65, STAT1 and p-STAT1 expression than controls, which was decreased by protective film and silicon dressing. Zinc oxide reduced NF-κB p65, p-NF-κB p65, STAT1 and p-STAT1 expression. However, no significant differences were observed in NF-κB/p-NF-κB ratio and STAT1/p-STAT1 ratio among groups. Furthermore, serum IFN-γ, IL-1β, IL-2 and TNF-α levels were significantly elevated in trypsin and joint IAD rats. The upregulation of these cytokines was significantly inhibited after all three treatments. Among the three treatment methods, silicone dressing had the best therapeutic effect. Thus, these findings revealed that zinc oxide, painless skin protective film and silicone dressing could ameliorate the severity of IAD rat models, and that silicone dressing possessed the best therapeutic effect.