Substance P (SP) is a tachykinin expressed by various cells in the nervous and immune systems. SP is predominantly released by neurons and exerts its biological and immunological effects through the neurokinin receptors, primarily the neurokinin-1 receptor (NK1R). SP is essential for maintaining ocular surface homeostasis, and its reduced levels in disorders like diabetic neuropathy disrupt the corneal tissue. It also plays an essential role in promoting corneal wound healing by promoting the migration of keratocytes. In this review, we briefly discuss the structure, expression, and function of SP and its principal receptor NK1R. In addition, SP induces pro-inflammatory effects through autocrine or paracrine action on the immune cells in various ocular surface pathologies, including dry eye disease, herpes simplex virus keratitis, and Pseudomonas keratitis. We provide an in-depth review of the pathogenic role of SP in various ocular surface diseases and several new approaches developed to counter the immune-mediated effects of SP either through modulating its production or blocking its target receptor.

P 物质 (SP) 是一种速激肽，由神经和免疫系统中的各种细胞表达。SP 主要由神经元释放，并通过神经激肽受体（主要是神经激肽-1 受体 (NK1R)）发挥其生物和免疫作用。SP 对于维持眼表稳态至关重要，在糖尿病神经病变等疾病中，SP 水平降低会破坏角膜组织。它还通过促进角膜伤口的迁移，在促进角膜伤口愈合方面发挥重要作用。角膜细胞。在这篇综述中，我们简要讨论了 SP 及其主要受体 NK1R 的结构、表达和功能。此外，SP 通过对各种眼表病变中的免疫细胞的自分泌或旁分泌作用诱导促炎作用，包括干眼病、单纯疱疹病毒角膜炎和假单胞菌角膜炎。我们深入回顾了 SP 在各种眼表疾病中的致病作用，并开发了几种通过调节其产生或阻断其靶受体来对抗 SP 的免疫介导作用的新方法。