Hydrogen-rich saline ameliorates the retina against light-induced damage in rats

Abstract

Oxidative reactions are thought to be a major cause of light-induced retinal degeneration. This study was designed to investigate the effects of hydrogen-rich saline (HRS) on the prevention and treatment of light-induced retinal injury in rats. Male Sprague-Dawley rats were divided randomly into three groups: light damage, HRS prevention (5 ml/kg, 30 min before intensive light exposure), and HRS treatment (5 ml/kg per day for 5 days, after intensive light exposure), respectively. The right eye of each rat was exposed to 5000 lux constant white light-emitting diode (LED) light for 3 h, and the left eye was covered to serve as the blank control. Electroretinograms were recorded 5 days later, and the thickness of the outer nuclear layer (ONL) was measured after hematoxylin and eosin (H&E) staining. The results showed that the electroretinogram b-wave amplitudes and the mean ONL thicknesses of rats were significantly greater in the HRS prevention (P < 0.001) and treatment (P < 0.001) groups than in the light damage. These results indicated that peritoneal injection of HRS provides protection and treatment against light-induced retinal degeneration in rats.

Figure 1

Annular illumination box for light-induced retinal damage in rats.

Figure 2

Responses for the dark-adapted conditions were detected at an intensity of 3.0 cd.s.m^-2. The ERG waves for the dark-adapted condition were detected (0.01 cd.s.m-2 ERG, 3.0 cd.s.m-2 ERG, and 3.0 cd.s.m-2 Ops ). Scotopoic ERGs responses were decreased larger in light damage than prevention and treatment groups compared with blank control.

Figure 3

Representative histology of the superior retina (measured at 1–2 mm starting at the optic nerve head) in age P56 SD rats, 5 days after light exposure. The unexposed retina is shown in panel A, and the retina that was injected with HRS after light exposure is shown in panel B. The retina that was injected with HRS before light exposure is shown in panel C, and the light-exposed retina is shown in panel D. Scale bar, 50 μm.

Figure 4

Morphometric analysis across the vertical meridians of retinas in SD rats reared in dim cyclic light. Black lines: unexposed to intense light; red lines: rats exposed at P56 and then maintained in darkness for 5 days; blue lines: HRS was given after light exposure; green lines: after HRS was given for 30 min, rats were exposed to light. The sample size was six rats per condition, with six ONL measurements per data point.