The aim of this study was to explore the neuroprotective effects of the P2X7 receptor antagonist A740003 on retinal ganglion cells (RGCs) in chronic intraocular hypertension (COH) experimental glaucoma mouse model. Bioinformatics was used to analyze the glaucoma-related genes. Western blot, real-time fluorescence quantitative PCR, and immunofluorescence staining techniques were employed to explore the mechanisms underlying the neuroprotective effects of A740003 on RGCs in COH retinas. Bioinformatic analysis revealed that oxidative stress, neuroinflammation, and cell apoptosis were highly related to the pathogenesis of glaucoma. In COH retinas, intraocular pressure elevation significantly increased the levels of translocator protein, a marker of microglial activation, which could be reversed by intravitreal preinjection of A740003. A740003 also suppressed the increased mRNA levels of proinflammatory cytokines interleukin (IL) 1β and tumor necrosis factor α in COH retinas. In addition, although the mRNA levels of anti-inflammatory cytokine IL-4 and IL-10 were kept unchanged in COH retinas, administration of A740003 could increase their levels. The mRNA and protein levels of Bax and cleaved caspase-3 were increased in COH retinas, which could be partially reversed by A740003, while the levels of Bcl-2 kept unchanged in COH retinas with or without the injections of A740003. Furthermore, A740003 partially attenuated the reduction in the numbers of Brn-3a-positive RGCs in COH mice. A740003 could provide neuroprotective roles on RGCs by inhibiting the microglia activation, attenuating the retinal inflammatory response, reducing the apoptosis of RGCs, and enhancing the survival of RGCs in COH experimental glaucoma.

Neuroinflammation, characterized by microglial activation and the release of multiple inflammatory mediators, is a key factor in acute glaucomatous injury leading to retinal ganglion cell (RGC) death and ultimately irreversible vision loss. Irisin, a novel exercise-induced myokine, has demonstrated anti-inflammatory activity in ischemia/reperfusion injuries across multiple organs and has displayed a significant neuroprotective role in experimental stroke disease models. This study examined the protective impact of irisin and investigated its potential mechanism involved in this process utilizing an acute ocular hypertension (AOH)-induced retinal injury model in mice and a microglia inflammation model induced by lipopolysaccharide (LPS). There was a transient downregulation of irisin in the retina after AOH injury, with parallel emergence of retinal neuroinflammation and RGC death. Irisin attenuated retinal and optic nerve damage and promotes the phenotypic conversion of microglia from M1 to M2. Mechanistically, irisin significantly upregulated the expression of integrin αVβ5, p-AMPK, and autophagy-related markers. Integrin αVβ5 was highly expressed on microglia but hardly expressed on RGC. The integrin αVβ5 inhibitor cilengitide, the AMPK inhibitor dorsomorphin, and the autophagy inhibitor 3-Methyladenine (3-MA) blocked the neuroprotective effects of irisin. Our results suggest irisin attenuates acute glaucoma-induced neuroinflammation and RGC death by activating integrin αVβ5/AMPK in microglia and promoting autophagy. It should be considered a potential neuroprotective therapy for acute glaucoma.

To evaluate the protective effect of gallic acid on the optic nerve by studying the inhibitory effect of gallic acid on oxidative stress in retinal ganglion cells. 100 male SD rats were randomly divided into four groups: normal control group, simple high IOP group, 0.5% gallic acid experimental group, and 1% gallic acid experimental group. HE staining, immunofluorescence, DHE staining, Western blot, and q-PCR were used to observe the antioxidant effect of gallic acid on the retina of acute ocular hypertension rats. HE staining of the retina of SD rats confirmed that the nucleus of RGCs was clear, the thickness of the RNFL was regular in the normal control group, and the nucleus of RGCs was ruptured and lysed in the simple high intraocular pressure (IOP) group and the gallic acid group, and the thickness of the RNFL was significantly thickened, but the thickness of the RNFL in the gallic acid group was significantly reduced compared with that in the simple high IOP group (p < 0.05). DHE staining showed that ROS content in the simple high IOP group was significantly increased compared with the normal control group, and ROS content was significantly decreased after the application of gallic acid (p < 0.05). Immunofluorescence staining with Brn-3a antibody confirmed that the number of RGCs was significantly reduced in the simple high IOP group compared with the normal control group, whereas after application of gallic acid, the number of RGCs was significantly more in the gallic acid group than in the simple high IOP group (p < 0.05). Western Blot and q-PCR confirmed that hypoxia-inducing factor 1α (HIF-1α) protein content and transcription level were significantly increased in the retinal tissue of the simple high IOP group, and gallic acid could inhibit HIF-1α protein content (p < 0.05) and reduce transcription factor level (p < 0.05). Gallic acid exerts a protective effect on RGC by inhibiting oxidative stress in rats with acute IOP elevation.

Ocular hypertension (OHT) refers to a condition in which the intraocular pressure increases without causing glaucomatous optic nerve changes or visual field damage. The incidence rate of OHT in people over 40 years old is as high as 4% to 10%. According to the OHT Treatment Study (OHTS), the incidence of primary open angle glaucoma (POAG) among OHT patients is increasing year by year, so it is necessary to conduct long-term follow-up. This article elaborates on five major risk factors for the progression of OHT to POAG: age, intraocular pressure, vertical cup-disc ratio, pattern standard deviation of visual field, and central corneal thickness. It also summarizes other potential risk factors, such as long-term fluctuations in intraocular pressure, asymmetry of intraocular pressure and visual field between the two eyes, structural phenotypes of the optic disk, and optic disk hemorrhage. Predicting the risk of OHT progression to POAG based on risk factors, patients with different risk levels require different timing for treatment initiation and follow-up intervals. Those with higher risks should start preventive treatment earlier and have shorter follow-up intervals. Both drug therapy and selective laser trabeculoplasty can serve as initial treatment options for OHT. Combining evidence-based medicine research and individualized evaluation of treatment can enhance the clinical diagnosis and treatment level of OHT.
高眼压症是指眼压升高但未引起青光眼性视神经改变或视野损伤的一种状态，在40岁以上人群中的患病率高达4%~10%。美国高眼压症治疗研究（OHTS）指出，高眼压症患者的原发性开角型青光眼（POAG）发病率逐年上升，因此有必要对其进行长期随访。本文详述了高眼压症进展为POAG的五大基本危险因素，包括年龄、眼压、垂直杯盘比、视野模式标准差和中央角膜厚度，并介绍了其他潜在危险因素，如眼压的长期波动、双眼眼压及视野的不对称性、视盘的结构内表型及视盘出血。根据危险因素可预测高眼压症进展为POAG的风险，不同风险的患者开始治疗的时机和随访时间间隔不同，风险大者应更早开始预防性治疗，且随访间隔时间较短。药物治疗和选择性激光小梁成形术（SLT）均可作为高眼压症的初始治疗方式。结合循证医学研究证据和个体化评估治疗，可更有效地提高高眼压症的临床诊疗水平。.

Efficient topical drug delivery remains a significant challenge in glaucoma management. Although nanoparticle formulations offer considerable promise, their complex preparation processes, co-delivery issues, and batch consistency have hindered their potential. A scalable fabrication strategy is developed here for preparing solid drug nanoparticles (SDNs) with enhanced drug delivery efficiency. Utilizing hydrophobic antiglaucoma drugs brimonidine (BM) and betaxolol (BX), uniform fixed combination BM/BX SDNs are fabricated through a continuous process, improving batch-to-batch consistency for combined glaucoma treatment. With trehalose being used as a lyoprotectant, BM/BX SDNs can be stored as dry powder and easily reconstituted in phosphate buffered saline. Importantly, reconstituted BM/BX SDNs form clear, homogenous solutions, and exhibit negligible cytotoxicity and irritation, making them well-suited for topical administration as eyedrops. Ex vivo and in vivo studies demonstrated that topically applied BM/BX SDNs permeate through the cornea significantly (about two fold to three fold) compared to their hydrophilic counterparts, i.e., brimonidine tartrate, and betaxolol hydrogen chloride. Notably, BM/BX SDNs displayed consistent intraocular pressure lowering effects in vivo in both normotensive rats and glaucoma mice. Collectively, this study demonstrates the potential of the scalable fabrication strategy and the resultant BM/BX SDNs for improving glaucoma management through eyedrops.

Glaucoma, the leading cause of irreversible blindness worldwide, is characterized by neurodegeneration and neuroinflammation with retinal NAD/NADP and GSH decline. Nicotinamide adenine dinucleotide (NAD)/NAD phosphate (NADP) and glutathione (GSH) are two redox reducers in neuronal and glial metabolism. However, therapeutic strategies targeting NAD/NADP or GSH do not exert ideal effects, and the underlying mechanisms are still poorly understood. We assessed morphological changes in retinal ganglion cells (RGCs), the affected neurons in glaucoma, and Müller cells, the major glial cells in the retina, as well as the levels of phosphorylated p38 (p-p38) and Caspase-3 in glaucoma patients. We constructed a modified chronic ocular hypertensive rat model and an oxygen-glucose deprivation (OGD) cell model. After applying NADPH and N-acetylcysteine (NAC), a precursor to cysteine, the rate-limiting substrate in GSH biosynthesis, to cells, apoptosis, axonal damage and peroxidation were reduced in the RGCs of the NAC group and p-p38 levels were decreased in the RGCs of the NADPH group, while in stimulated Müller cells cultured individually or cocultured with RGCs, gliosis and p38/MAPK, rather than JNK/MAPK, activation were inhibited. The results were more synergistic in the rat model, where either NADPH or NAC showed crossover effects on inhibiting peroxidation and p38/MAPK pathway activation. Moreover, the combination of NADPH and NAC ameliorated RGC electrophysiological function and prevented Müller cell gliosis to the greatest extent. These data illustrated conjoined mechanisms in glaucomatous RGC injury and Müller cell gliosis and suggested that NADPH and NAC collaborate as a neuroprotective and anti-inflammatory combination treatment for glaucoma and other underlying human neurodegenerative diseases.

Objective: The aim of this study was to synthesize the available evidence on the clinical efficacy of different relaxation exercises on intraocular pressure (IOP) reduction. Methods: A systemic search of PubMed, Embase, Cochrane CENTRAL, and Web of Science was undertaken from the earliest record to 10 April 2024. Peer-reviewed studies that reported on healthy individuals and glaucoma patients engaging in relaxation exercises for at least three weeks were included. The primary outcome was changes in IOP levels from baseline, before the commencement of relaxation exercises, to post-exercise. Our statistical analysis employed a random-effects model, with effect sizes reported using Hedges\' g. Results: Twelve studies were included, totaling 764 eyes (mean participant age ranging from 21.07 to 69.50 years). Relaxation exercises significantly reduced IOP, with Hedges\' g being -1.276 (95% CI: -1.674 to -0.879) and I2 = 84.4%. Separate subgroup analyses showed that breathing exercises (Hedges\' g = -0.860, p < 0.0001), mindfulness-based stress reduction (MBSR) (Hedges\' g = -1.79, p < 0.0001), and ocular exercises (Hedges\' g = -0.974, p < 0.0001) were associated with reduced IOP levels. The reduction in IOP following the relaxation exercises was found to be associated with baseline IOP either greater than (Hedges\' g = -1.473, p < 0.0001) or less than 21 mmHg (Hedges\' g = -1.22, p < 0.0001). Furthermore, this effect persisted with follow-up durations of less than (Hedges\' g = -1.161, p < 0.0001) and more than one month (Hedges\' g = -1.324, p < 0.0001). Conclusions: The current meta-analysis indicates that relaxation exercises can significantly reduce IOP levels. Relaxation exercises are a potential class of novel treatments for glaucoma patients that deserve further evaluation.

The carbonic anhydrase 2 (Car2) gene encodes the primary isoenzyme responsible for aqueous humor (AH) production and plays a major role in the regulation of intraocular pressure (IOP). The CRISPR-Cas9 system, based on the ShH10 adenovirus-associated virus, can efficiently disrupt the Car2 gene in the ciliary body. With a single intravitreal injection, Car2 knockout can significantly and sustainably reduce IOP in both normal mice and glaucoma models by inhibiting AH production. Furthermore, it effectively delays and even halts glaucomatous damage induced by prolonged high IOP in a chronic ocular hypertension model, surpassing the efficacy of clinically available carbonic anhydrase inhibitors such as brinzolamide. The clinical application of CRISPR-Cas9 based disruption of Car2 is an attractive therapeutic strategy that could bring additional benefits to patients with glaucoma.

BACKGROUND: NADPH oxidase (NOX), a primary source of endothelial reactive oxygen species (ROS), is considered a key event in disrupting the integrity of the blood-retinal barrier. Abnormalities in neurovascular-coupled immune signaling herald the loss of ganglion cells in glaucoma. Persistent microglia-driven inflammation and cellular innate immune system dysregulation often lead to deteriorating retinal degeneration. However, the crosstalk between NOX and the retinal immune environment remains unresolved. Here, we investigate the interaction between oxidative stress and neuroinflammation in glaucoma by genetic defects of NOX2 or its regulation via gp91ds-tat.
METHODS: Ex vivo cultures of retinal explants from wildtype C57BL/6J and Nox2 -/- mice were subjected to normal and high hydrostatic pressure (Pressure 60 mmHg) for 24 h. In vivo, high intraocular pressure (H-IOP) was induced in C57BL/6J mice for two weeks. Both Pressure 60 mmHg retinas and H-IOP mice were treated with either gp91ds-tat (a NOX2-specific inhibitor). Proteomic analysis was performed on control, H-IOP, and treatment with gp91ds-tat retinas to identify differentially expressed proteins (DEPs). The study also evaluated various glaucoma phenotypes, including IOP, retinal ganglion cell (RGC) functionality, and optic nerve (ON) degeneration. The superoxide (O2-) levels assay, blood-retinal barrier degradation, gliosis, neuroinflammation, enzyme-linked immunosorbent assay (ELISA), western blotting, and quantitative PCR were performed in this study.
RESULTS: We found that NOX2-specific deletion or activity inhibition effectively attenuated retinal oxidative stress, immune dysregulation, the internal blood-retinal barrier (iBRB) injury, neurovascular unit (NVU) dysfunction, RGC loss, and ON axonal degeneration following H-IOP. Mechanistically, we unveiled for the first time that NOX2-dependent ROS-driven pro-inflammatory signaling, where NOX2/ROS induces endothelium-derived endothelin-1 (ET-1) overexpression, which activates the ERK1/2 signaling pathway and mediates the shift of microglia activation to a pro-inflammatory M1 phenotype, thereby triggering a neuroinflammatory outburst.
CONCLUSIONS: Collectively, we demonstrate for the first time that NOX2 deletion or gp91ds-tat inhibition attenuates iBRB injury and NVU dysfunction to rescue glaucomatous RGC loss and ON axon degeneration, which is associated with inhibition of the ET-1/ERK1/2-transduced shift of microglial cell activation toward a pro-inflammatory M1 phenotype, highlighting NOX2 as a potential target for novel neuroprotective therapies in glaucoma management.

OBJECTIVE: Glaucoma is a multifactorial optic neuropathy with a high rate of irreversible visual loss, and its pathogenesis is complex and still unclear. Elevated intraocular pressure (IOP) is well recognized as the sole modifiable risk factor for the development of glaucoma in the majority of cases. This study aims to compare 2 different methods of inducing chronic ocular hypertension by circumlimbal suture or by laser burns in degree and lasting time of the IOP, different status of the retina and retinal ganglion cells (RGCs), and changes of the microstructure of neurons.
METHODS: The chronic ocular hypertension models were induced by 2 different ways. One kind of the models was built by unilateral circumlimbal suture (10/0) implantation (suture group), another kind of model was built by laser burns at trabecular meshwork and episcleral veins (laser group). The untreated contralateral eye served as the control group. Changes in IOP were observed and regularly monitored in the 2 groups of rats. HE staining was applied to observe the retinal and optic nerve pathology. Transmission electron microscope (TEM) was used to observe the mitochondrial morphology. RGCs were specifically labeled with Brn3b antibody and counted. The expression of caspase-3 was detected by Western blotting to clarify the apoptosis of RGCs.
RESULTS: Compared with the control group, IOP were significantly increased in the suture group and the laser group (both P<0.05). The suture group induced a 1.5-fold elevation of IOP, and sustained for 8 weeks. The laser group induced a 2-fold elevation of IOP for 12 weeks. Both methods could cause RGCs loss (both P<0.05), which were verified by pathology and immune staining of Brn3b. The expressions of caspase-3 were also increased (both P<0.05). The mitochondrial morphology became more fragment, which changed from long shape to round and small one under TEM in 2 models. For comparison, the pathology changes of retinal structure in suture group were not obviously than those in the laser group.
CONCLUSIONS: Circumlimbal suture can build an effective model of chronic elevated IOP and induce glaucomatous pathologic changes similar to those in the laser photocoagulation, but the pathologic changes are milder than those in laser photocoagulation. Compare with translimbal laser photocoagulation, equipment and skill demand for circumlimbal suture is less.
目的: 青光眼是一种多因素相关的视神经病变，致盲率高，其发病机制复杂，目前尚未明确。高眼压是目前唯一可调控的、与青光眼的发病密切相关的危险因素。本研究通过运用环角膜缘缝合与小梁网联合巩膜静脉激光光凝2种不同的方法建立慢性高眼压大鼠模型，比较2种模型的眼压升高程度和高眼压持续时间，视网膜形态损伤和视网膜神经节细胞(retinal ganglion cells，RGCs)损伤程度，以及超微结构改变等。方法: 建立2种慢性高眼压模型，分为环角膜缘缝合组(缝合组，用10/0尼龙线沿角巩膜缘缝合)和激光光凝组(激光组，激光灼烧小梁网联合巩膜外静脉)，并以其对侧眼作为对照组。观察并定期规律监测2组大鼠的眼压变化。采用大鼠视网膜切片HE染色观察2种慢性高眼压模型对视网膜和视神经病理学的影响，透射电镜(transmission electron microscope，TEM)观察慢性高眼压模型超微结构中线粒体形态的变化，大鼠视网膜铺片Brn3b抗体免疫荧光染色特异性标记RGCs并计数，蛋白质印迹法检测凋亡相关蛋白caspase-3的表达以明确RGCs的凋亡情况。结果: 与对照组相比，缝合组与激光组大鼠眼压均明显升高(均P<0.05)，其中缝合组的眼压最高升高1.5倍，眼压显著升高持续8周；激光组的眼压最高达对照组的2倍，持续12周。2组都会导致RGCs丢失，与Brn3b染色的结果相符，2组caspase-3表达水平均升高(均P<0.05)。而在TEM下，2组RGCs中的线粒体形态均变为碎片化，从正常的长条形变小、变圆。与激光组相比，缝合组视网膜形态学的病理变化较轻微。结论: 环角膜缘缝合可建立有效的慢性高眼压模型，诱导与激光光凝模型相似的青光眼性病理改变，但病理改变较激光光凝轻微。相较于激光光凝建模，环角膜缘缝合法对于设备要求和操作能力要求更低。.