Turkish Neurosurgery
INVESTIGATION OF DEMYELINATION AND REMYELIZATION PROCESSES OF THE COMPRESSED OPTIC CHIASM : AN EXPERIMENTAL MODEL
Emengen Atakan1, Anik Ihsan2, Kokturk Sibel3, Karson Ayşe4, Yilmaz Eren2, Başaran Emengen Ece5, Caklili Melih6, Anik Yonca 7, Ceylan Sureyya 8, Cabuk Burak2, Ceylan Savas2
1Kocaeli State Hospital, Neurosurgery, Kocaeli,
2Kocaeli University, Neurosurgery, Kocaeli,
3Istanbul University, Histology and Embryology, Istanbul,
4Kocaeli University, Physiology, Kocaeli,
5Kocaeli University, Ophthalmology, Kocaeli,
6Taksim Education and Research Hospital, Neurosurgery , Istanbul,
7Kocaeli University, Radiology, Kocaeli,
8Kocaeli University, Histology and Embryology, Kocaeli,
DOI: 10.5137/1019-5149.JTN.41743-22.2

Aim:The most important symptoms of pituitary adenomas and the main indications for surgical intervention are loss of visual field and visual acuity. Structural and functional changes in axonal flow have been reported due to surgical decompression after operations for sellar lesions, and recovery rates remain unknown. Using an experimental model similar to the compression of pituitary adenomas on the optic chiasm, we demonstrated demyelination and remyelination of the optic nerve histologically using electron microscopy.Material and Methods:The animals were fixed to a stereotaxic device under deep anesthesia, and a balloon catheter was placed under the optic chiasm through the burr hole opened in front of the bregma according to the brain atlas. According to the amount of pressure applied, the animals were divided into five groups: demyelination and remyelination groups. The fine structures of the tissues obtained were evaluated using electron microscopy.Results:Each group contained eight rats. We found a significant difference in the severity of degeneration when comparing group 1 with group 5 (p < 0.001); there was no degeneration in group 1 rats and severe degeneration in all of the group 5 rats. Oligodendrocytes were found in all rats in group 1 and none of the rats in no group 2. The nuclei were preserved in the group 1 rats but damaged in all of the group 5 rats. There were no lymphocytes or erythrocytes in group 1 and all positives in group 5.Conclusion:This technique, which induced degeneration without causing damage to the optic nerve with toxic or chemical agents, revealed Wallerian degeneration similar to tumoral compression. After compression relief, the optic nerve remyelination process can be better understood, particularly for sellar lesions. In our opinion, this model may guide future experiments to identify protocols to induce and accelerate remyelination.

Corresponding author : Emengen Atakan