Department of Human Anatomy and Neurobiology, School of Basic Medical Sciences, Central South University, Changsha 410013, China.
CNS Neurol Disord Drug Targets. 2021 Oct 26;20(3):285-297. doi: 10.2174/1871527319666201012125149.
Glaucoma is a multifactorial optic neuropathy progressively characterized by structural loss of Retinal Ganglion Cells (RGCs) and irreversible loss of vision. High Intraocular Pressure (HIOP) is a high-risk factor for glaucoma. It has been reported that the mechanisms of the loss of RGCs are explored in-depth after acute HIOP injury, such as apoptosis, autophagy, and necrosis. However, pyroptosis, a novel type of pro-inflammatory cell programmed necrosis, is rarely reported after HIOP injury. Research studies also showed that melatonin (MT) possesses substantial anti-inflammatory properties. However, whether melatonin could alleviate retinal neuronal death, especially pyroptosis, by HIOP injury is still unclear.
This study explored pyroptosis of retinal neurons and the effects of melatonin in preventing retinal neurons from pyroptosis after acute HIOP injury.
An acute HIOP model of rats was established by increasing the IOP followed by reperfusion. Western Blot (WB) was adopted to detect molecules related to pyroptosis at the protein level, such as GSDMD, GASMDp32, Caspase-1, and caspase-1 p20, and the products of inflammatory reactions, such as IL -18 and IL-1β. At the same time, immunofluorescence (IF) was used to co-localize caspase-1 with retinal neurons to determine the position of caspase-1 expression. Morphologically, ethidium homodimer III staining, a method commonly used to evaluate cell death, was carried out to stain dead cells. Subsequently, Lactate Dehydrogenase (LDH) cytotoxicity assay kit was used to quantitatively analyze the LDH released after cell disruption.
The results suggested that pyroptosis played a vital role in retinal neuronal death, especially in the Ganglion Cell Layer, by acute HIOP injury and peaked at 6h after HIOP injury. Furthermore, it was found that melatonin (MT) might prevent retinal neurons of pyroptosis via NF-κ B/NLRP3 axis after HIOP injury in rats.
Melatonin treatment might be considered a new strategy for protecting retinal neurons against pyroptosis following acute HIOP injury.
青光眼是一种多因素的视神经病变，其特征为视网膜神经节细胞（RGCs）的结构进行性丧失和视力不可逆转的丧失。高眼压（HIOP）是青光眼的高危因素。据报道，急性 HIOP 损伤后深入研究了 RGCs 丧失的机制，如细胞凋亡、自噬和坏死。然而，细胞焦亡，一种新型的促炎细胞程序性坏死，在 HIOP 损伤后很少被报道。研究还表明，褪黑素（MT）具有显著的抗炎特性。然而，褪黑素是否能减轻 HIOP 损伤引起的视网膜神经元死亡，特别是细胞焦亡，仍不清楚。
本研究探讨了急性 HIOP 损伤后视网膜神经元的细胞焦亡及褪黑素对预防视网膜神经元细胞焦亡的作用。
通过增加眼内压（IOP）再灌注来建立大鼠急性 HIOP 模型。采用 Western Blot（WB）检测与细胞焦亡相关的分子，如 GSDMD、GASMDp32、Caspase-1 和 Caspase-1 p20，以及炎症反应产物，如 IL-18 和 IL-1β。同时，采用免疫荧光（IF）共定位 Caspase-1 与视网膜神经元，以确定 Caspase-1 表达的位置。形态学上，采用常用于评估细胞死亡的 ethidium homodimer III 染色法染色死亡细胞。随后，使用乳酸脱氢酶（LDH）细胞毒性检测试剂盒定量分析细胞破裂后释放的 LDH。
结果表明，细胞焦亡在急性 HIOP 损伤后导致视网膜神经元死亡中起重要作用，特别是在神经节细胞层，在 HIOP 损伤后 6 小时达到高峰。此外，发现褪黑素（MT）可能通过 HIOP 损伤后 NF-κB/NLRP3 轴预防大鼠视网膜神经元的细胞焦亡。
褪黑素治疗可能被认为是一种保护急性 HIOP 损伤后视网膜神经元免受细胞焦亡的新策略。
