Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan; Advanced Research Laboratory, Hoyu Co., Ltd., Nagakute, Aichi, Japan.
Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan.
Neurosci Lett. 2020 Feb 16;720:134784. doi: 10.1016/j.neulet.2020.134784. Epub 2020 Jan 24.
Cleaning products such as soaps, shampoos, and detergents are comprised mainly of surfactants, agents known to cause dermatitis and cutaneous hypersensitivity characterized by itching, stinging, and burning of the skin and scalp. However, the mechanisms underlying surfactant-induced cutaneous hypersensitivity remain unclear. In the present study, we investigated the mechanisms of cutaneous hypersensitivity in mice treated with the detergent sodium dodecyl sulfate (SDS). Repeated SDS application to the skin induced inflammation, xeroderma, and elongation of peripheral nerves into the epidermis. The number of neurons immunopositive for c-Fos, a well known marker of neural activity, was substantially higher (+441%) in spinal dorsal horn (SDH) lamina I-II (but not lamina III-VI) of SDS-treated mice compared to vehicle-treated mice. In vivo extracellular recording revealed enhanced spontaneous (+64%) and non-noxious mechanical stimulation-evoked firing (+139%) of SDH lamina I-II neurons in SDS-treated mice, and stimulation-evoked neuronal firing was sustained (+5333%) even after stimulation. The number of GFAP-positive (activated) astrocytes, but not Iba1-positive microglia, was also elevated (+137%) in SDH lamina I-II of SDS-treated mice compared to vehicle-treated mice. Peripheral nerve elongation and hyperexcitability of afferent or SDH neurons, possible associated with the activation of spinal astrocytes, may underlie cutaneous hypersensitivity induced by surfactants.
清洁产品，如肥皂、洗发水和洗涤剂，主要由表面活性剂组成，这些活性剂已知会引起皮炎和皮肤过敏，表现为皮肤和头皮瘙痒、刺痛和烧灼感。然而，表面活性剂引起的皮肤过敏的机制尚不清楚。在本研究中，我们研究了用洗涤剂十二烷基硫酸钠（SDS）处理的小鼠皮肤过敏的机制。SDS 反复应用于皮肤会引起炎症、皮肤干燥和外周神经延伸到表皮。用 SDS 处理的小鼠的脊髓背角（SDH）I-II 层（而非 III-VI 层）中，c-Fos 免疫阳性神经元的数量（一种已知的神经活动标志物）显著增加（+441%），而与载体处理的小鼠相比。体内细胞外记录显示，SDS 处理的小鼠的 SDH I-II 层神经元自发性（+64%）和非伤害性机械刺激诱发的放电（+139%）增强，刺激诱发的神经元放电甚至在刺激后仍持续（+5333%）。与载体处理的小鼠相比，SDS 处理的小鼠的 SDH I-II 层中 GFAP 阳性（激活）星形胶质细胞的数量也增加（+137%），而 Iba1 阳性小胶质细胞的数量没有增加。外周神经延伸和传入或 SDH 神经元的过度兴奋，可能与脊髓星形胶质细胞的激活有关，可能是表面活性剂引起的皮肤过敏的基础。
