β-1,3-glucan attenuates neuronal cell death after transient retinal ischemia and reperfusion

Abstract

The neuroprotective effect of intravitreally injected β-1,3-glucan was examined in a rat model of transient retinal ischemia. Retinal function and morphology were assessed in both control rats (Intact), and in rats administered β-1,3-glucan after ischemic damage induced by elevation of intraocular pressure (IOP) to 130 mmHg for 45 min. β-1,3-Glucan was intravitreally injected into male SD rats, with a final vitreal concentration of 5 μg/eye. Retinal function was assessed by electroretinography, and retinal morphology was assessed by light microscopy and TUNEL assay (n = 3 for Intact, and n = 6 for β-1,3-glucan and Vehicle). Morphometric analysis of retinal ganglion cells (RGCs) and the inner plexiform layer (IPL) showed decreased RGC number and thinner IPL in the eyes of Intact rats compared with those injected with β-1,3-glucan. TUNEL assay results showed that the retinas of eyes injected with β-1,3-glucan were similar to those of Intact eyes (the left eyes of the SD rats). However, the retinas of Vehicle eyes differed in RGC and IPL layer from β-1,3-glucan injected eyes after transient retinal ischemia. Electroretinograms (ERGs) showed that the β-1,3-glucan-administered rats had significantly more protective b-wave amplitudes compared with the Vehicle group. β-1,3-Glucan exhibits a neuroprotective effect in a transient retinal ischemia model of retinal injury in rats.