Neuroprotective effect of minocycline on rat retinal ischemia-reperfusion injury

Purpose: To examine the neuroprotective effect of minocycline on retinal ischemia-reperfusion (IR) injury in rats and investigate its possible mechanism of action. Methods: Retinal IR injury was established by increasing the intraocular pressure in rats up to 110 mmHg for 60 min. The animals with retinal IR injury were intraperitoneally injected with 22.5 mg/kg minocycline twice a day for 14 days. The control group received the same amount of saline. Subsequently, funduscopic examination, retinal thickness measurement, retinal microvascular morphology, full-field electroretinography (ERG), retinal apoptotic cell count, and remaining retinal ganglion cell (RGC) count were performed. The expression of iNOS, Bax, Bcl2, IL-1 alpha, IL-6, TNF-alpha, caspase-3, GFAP, Iba-1, Hif-1 alpha, and Nrf2 was examined with real-time PCR and western blotting. Results: Minocycline treatment prevented IR-induced rat retinal edema and retinal cells apoptosis at the early stage and alleviated retina atrophy, blood vessel tortuosity, functional photoreceptor damage, and RGC degeneration at the late stage of the IR injury. At the molecular level, minocycline affected retinal gene and protein expression induced by IR. Conclusions: The results suggested that minocycline has a neuroprotective effect on rat retinal IR injury, possibly through anti-inflammation, antiapoptosis, antioxidation, and inhibition of microglial activation.