Protection of the retina by rapid diffusion of hydrogen: administration of hydrogen-loaded eye drops in retinal ischemia-reperfusion injury.

Abstract

Using a rat model of retinal ischemia-reperfusion (I/R) injury induced by transient intraocular pressure elevation, hydrogen-saturated saline eye drops were applied continuously to the ocular surface during ischemia and reperfusion phases. Vitreous hydrogen concentration rose rapidly after administration, accompanied by a reduction in hydroxyl radical levels. Quantification one day post-injury showed decreased apoptotic cell counts and fewer cells positive for oxidative stress markers (4-hydroxynonenal and 8-hydroxy-2-deoxyguanosine). Seven days after injury, retinal thickness recovery exceeded 70% compared to untreated controls, and activation of Müller glia, astrocytes, and microglia was observed. These findings indicate that topically applied hydrogen-rich drops can rapidly diffuse into ocular tissues and confer neuroprotective and antioxidative effects in acute retinal I/R injury.

Mechanism

Hydrogen diffuses rapidly from the ocular surface into the vitreous, where it selectively scavenges hydroxyl radicals, reducing oxidative stress markers and suppressing apoptosis in retinal neurons following ischemia-reperfusion injury.