Chitosan-selenium nanoparticles prevent retinal ganglion cell apoptosis in glaucoma via activation of the PI3K/Akt/Nrf2 antioxidant axis

Glaucoma is a prominent global cause of irreversible vision loss, fundamentally driven by the continuous degeneration and ultimate death of retinal ganglion cells (RGCs), in which persistent oxidative stress plays a pivotal role. While selenium (Se) offers robust endogenous antioxidant defense, the severe toxicity and narrow therapeutic window of inorganic selenium strictly limit its application. To overcome this critical bottleneck, chitosan-functionalized selenium nanoparticles (CS-SeNPs) are engineered. This strategic nanomodification effectively shields the inherent toxicity of free selenium while conferring improved colloidal stability and biocompatibility. Clinically, systemic Se levels in patients with primary open-angle glaucoma (POAG) are found to be significantly diminished compared to healthy controls. Mechanistically, transcriptome sequencing reveals that CS-SeNPs function through the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) pathway to upregulate the downstream nuclear factor erythroid 2-related factor 2/heme oxygenase-1 (Nrf2/HO-1) antioxidant axis, reducing intracellular oxidative stress and apoptosis. In vivo, an intravitreal administration strategy for CS-SeNPs is established. In a rat model of acute ocular hypertension (AOH), this targeted local delivery reduces oxidative damage, preserves retinal hierarchical architecture, and restores visual electrophysiological function. These findings identify systemic Se deficiency as a clinical hallmark of POAG and demonstrate that intravitreal CS-SeNPs offer a promising, intraocular pressure-independent nanotherapeutic strategy for glaucomatous neuroprotection.