Effect of High-Dosage Methylprednisolone on Experimental Trauma of Optic Nerve

Kim, In Taek; Hong, Sung Pyo; Sohn, Yoon Kyung

Abstract

High-dose methylprednisolone (MP) has been shown to play an important role in traumatic optic nerve injury. The purpose of this study was to investigate histopathologic changes of the injured optic nerve with time course after experimental trauma to the optic nerve had been induced. The optic nerve trauma was made by rotating the eyeball in rabbits. Twelve rabbits were divided into three groups (Group 1; 2 weeks, Group 2; 1 month, and Group 3; 2 months) according to time course after MP administration. Each group comprised of control group and treatment group. MP significantly reduced damage of the myelinated nerve and gliosis in comparision with the control group, when MP was administered IV immediately after trauma in the treatment group at a bolus of 30mg/kg, two times for 3 days, with a subsequent continuous MP infusion at 30mg/kg for 4 days. And massive gliosis and damage of the myelinated nerve in the control group were oberserved on electron microscopy. However, we could not find PMNLs, macrophages, and proliferation of fibroblast in both the control group and treatment group. It is possible that high-dose MP protects further damage of the injured optic nerve and that the beneficial effect is partially due to its antioxidant rather than its anti-inflammatory effect. This histopathologic study indicated that high-dose MP might improve the neurological outcome in the injured optic nerve.