Glial Cells and Retinal Nerve Fibers Morphology in the Optic Nerves of Streptozotocin‑induced Hyperglycemic Rats

Purpose: This study analyzes the structures of optic nerve elements, i.e., glial cells and nerve fibers, in an STZ‑induced hyperglycemic animal model. Morphological changes in glial elements of the optic nerve in hyperglycemic and normoglycemic animals were compared. Methods: Transmission electron microscopy, histochemistry, immunohistochemistry, and morphometry were used in this study. Results: Hyperglycemia increased the numbers of inner mesaxons and axons with degenerative profiles. Furthermore, it led to both an increase in the amount of debris and in the numbers of secondary lysosomic vesicles in glial cytoplasm. Hyperglycemia also led to a decrease in glial fibrillary acidic protein expression and an increase in periodic acid‑Schiff‑positive deposits in the optic nerves of hyperglycemic animals. Conclusion: We conclude that the damage to the structural elements observed in our animal models contributes to the pathogenesis of optic neuropathy in the early stages of diabetes.