Investigation On Pathological Mechanism Of Acute And Chronic Optic Nerve Injury In Cats

Objective: To investigate the the pathological changes of the astrcytes and the neuron after acute and chronic compression injury of the optic nerve.Methods: (1) Establish an acute optic nerve compression injury model: Pterional approach was performed with the aid of binocular microscope. After retraction of the brain the optic nerve was exposed, squeezing the optic nerve for a period of 20 seconds near the optic foramen with a vascular clip..(2) Establish a chronic optic nerve compression injury model: Pterional approach was performed with the aid of binocular microscope. After retraction of the brain the optic nerve was exposed, implanting a detachable silion balloon connected by thin silion rubber tubing.Results:The VEP manifestation as the amplitude decreased and the latency prolonged. Marker,GFAP for astrocyte decreased their activity in the area of direct mechnical injury, increased their activity in the proximal section. Features of apoptosis were clearly present in the retina and LGB.Conclusion:The acute and chronic optic nerve compression model are stable for the investigation on the optic nerve injury. The neurons degeneration is posterior to the astrocytes degeneration. The changes of VEP are different in acute and chronic injury.