Surico Pier Luigi, Naderi Amirreza, Singh Rohan Bir, Kahale Francesca, Farsi Yeganeh, Lee Seokjoo, Musayeva Aytan, Chen Yihe, Dana Reza
Laboratory of Ocular Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.
Laboratory of Ocular Immunology, Transplantation and Regeneration, Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.
Exp Eye Res. 2025 Feb;251:110230. doi: 10.1016/j.exer.2025.110230. Epub 2025 Jan 4.
Substance P (SP) expressed by corneal nerves, is an 11-amino acid long neuropeptide from the tachykinin family, encoded by the Tac1 gene, and binds to neurokinin receptors. SP overexpression is associated with various pathological responses in the cornea including vasodilation, pain, inflammation, and angiogenesis in the normally avascular tissue. This study investigates the role of neurokinin-1 receptor (NK-1R) mediated signaling in nociception, nerve regeneration, and neuronal activation following mechanical corneal injury in mice. Corneal injuries were induced in age- and sex-matched C57BL/6 mice by removing corneal epithelium and partial anterior stroma. Following injury, mice were treated with either L-733,060, an NK-1R antagonist, or vehicle, administered topically twice daily for 21 days. Corneal SP levels were measured using ELISA, and nerve regeneration was assessed by quantifying corneal nerve fiber density (CNFD) via β-Tubulin III staining. Gene expression of neuronal markers (ATF3, GFAP, cFos, TRPV1, and TRPM8) in the trigeminal ganglia was measured using qPCR. Pain responses were evaluated using the eye-wiping test (EWT) and palpebral ratio (PR). Results indicated a persistent increase in corneal SP post-injury, significantly reduced by NK-1R antagonism. At 21 days, NK-1R antagonist-treated mice showed higher CNFD, reduced expression of neuronal activation markers, and lower pain perception compared to controls. These findings suggest that SP/NK-1R signaling is critical in corneal nociception post-injury, and its inhibition reduces pain, prevents neuronal hyperactivation, and supports nerve regeneration.
由角膜神经表达的P物质（SP）是一种来自速激肽家族的11个氨基酸长的神经肽，由Tac1基因编码，并与神经激肽受体结合。SP的过度表达与角膜中的各种病理反应有关，包括血管舒张、疼痛、炎症以及正常无血管组织中的血管生成。本研究调查了神经激肽-1受体（NK-1R）介导的信号在小鼠角膜机械损伤后的伤害感受、神经再生和神经元激活中的作用。通过去除角膜上皮和部分前基质，在年龄和性别匹配的C57BL/6小鼠中诱导角膜损伤。损伤后，小鼠每天局部给予NK-1R拮抗剂L-733,060或赋形剂，持续21天。使用酶联免疫吸附测定法（ELISA）测量角膜SP水平，并通过β-微管蛋白III染色定量角膜神经纤维密度（CNFD）来评估神经再生。使用定量聚合酶链反应（qPCR）测量三叉神经节中神经元标志物（ATF3、GFAP、cFos、TRPV1和TRPM8）的基因表达。使用擦眼试验（EWT）和睑裂比例（PR）评估疼痛反应。结果表明，损伤后角膜SP持续增加，NK-1R拮抗作用可使其显著降低。在21天时，与对照组相比，接受NK-1R拮抗剂治疗的小鼠显示出更高的CNFD、神经元激活标志物表达降低以及疼痛感知降低。这些发现表明，SP/NK-1R信号在损伤后角膜伤害感受中至关重要，抑制该信号可减轻疼痛、防止神经元过度激活并支持神经再生。
