Post‐inflammatory hyperpigmentation (PIH) is a common cutaneous condition that can cause a disfigured appearance. However, the pathophysiology of PIH remains poorly understood, at least in part, because an appropriate animal model for research has not been established. In order to analyze the pathomechanism of PIH, we successfully induced PIH in a hairless version of transgenic mice (hk14‐SCF Tg/HRM) that have a human‐type epidermis containing melanin by repeated hapten application of 2,4‐dinitrofluorobenzene. Histopathologic observation showed epidermal hyperplasia, predominant infiltrations of inflammatory cells, and melanin‐containing cells in the dermis just after elicitation of the atopic dermatitis‐like condition. At week 2, the findings were similar to the characteristics of PIH, that is, an increase of melanin without spongiosis or liquid degeneration in the epidermis and an increase in dermal melanophages. Dynamic analysis of melanin showed that the melanin in the dermis remained for a longer duration than in the epidermis. Furthermore, immunohistochemical staining revealed that the majority of cells containing melanin were positive for the anti‐CD68 antibody, but negative for the anti‐F4/80 antibody. These data suggest that novel treatments of PIH should be targeted against macrophages and should eventually lead to the development of new treatment modalities.

中文翻译：

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炎症后色素沉着过度小鼠模型的建立。

炎症后色素沉着过度 (PIH) 是一种常见的皮肤病，可导致外观变形。然而，对 PIH 的病理生理学仍然知之甚少，至少部分是因为尚未建立合适的研究动物模型。为了分析 PIH 的发病机制，我们通过重复使用 2,4-二硝基氟苯半抗原，在具有含有黑色素的人型表皮的无毛转基因小鼠（hk14-SCF Tg/HRM）中成功诱导了 PIH。组织病理学观察显示，在引发特应性皮炎样病症后，真皮中表皮增生、炎症细胞主要浸润和含有黑色素的细胞。在第 2 周，结果与 PIH 的特征相似，即，黑色素增加，但表皮无海绵状组织增生或液体变性，真皮黑色素细胞增加。黑色素的动态分析表明，真皮中的黑色素比表皮中的黑色素保留时间更长。此外，免疫组织化学染色显示，大多数含有黑色素的细胞抗 CD68 抗体呈阳性，但抗 F4/80 抗体呈阴性。这些数据表明 PIH 的新疗法应该针对巨噬细胞，并最终导致新治疗方式的发展。免疫组织化学染色显示，大多数含有黑色素的细胞抗 CD68 抗体呈阳性，但抗 F4/80 抗体呈阴性。这些数据表明 PIH 的新疗法应该针对巨噬细胞，并最终导致新治疗方式的发展。免疫组织化学染色显示，大多数含有黑色素的细胞抗 CD68 抗体呈阳性，但抗 F4/80 抗体呈阴性。这些数据表明 PIH 的新疗法应该针对巨噬细胞，并最终导致新治疗方式的发展。