Statin inhibits leukocyte-endothelial interaction and prevents neuronal death induced by ischemia-reperfusion injury in the rat retina.

Retinal ishchemia-induced neuronal death is believed to be a direct causal process in the development of many ocular diseases. The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, statin, is known to improve endothelial function in proinflammatory conditions. To investigate the effects of statin on leukocyte accumulation during ischemia-reperfusion injury and on subsequent retinal damage. Transient retinal ischemia was induced in Long-Evans rats for 60 minutes using temporal ligation of the optic nerve. Leukocyte-endothelial interactions in the postischemic retina were evaluated in vivo with a scanning laser ophthalmoscope. Statin was administered 5 minutes before the induction of retinal ischemia. P-selectin and intercellular adhesion molecule-1 (ICAM-1) gene expression in the postischemic retina were studied with the semiquantitative polymerase chain reaction. Histologic studies were carried out to evaluate retinal damage. The preadministration of statin attenuated the rolling and accumulation of leukocytes, decreased P-selectin and ICAM-1 expression, and reduced the number of apoptotic cells in the retina. Furthermore, histologic evaluation 168 hours after reperfusion showed that statin significantly diminished the resultant retinal tissue damage. The neuroprotective effect of statin was abolished when it was administered along with a nitric oxide synthase inhibitor, nitroglycerine-nitro-L-arginine methyl ester. Statin may exert neuroprotective effects by inhibiting leukocyte-endothelial interaction through the release of nitric oxide from the endothelium. As a result of its efficacy in preventing retinal neuronal death, statin may be developed into a novel therapeutic modality for many ocular ischemic diseases.