ABSTRACT
PURPOSE: To investigate the cellular changes and cellular characteristics of myelinated nerve fiber, unmyelinated nerve fiber and Schwann cell under the culture conditions of the explant of the long ciliary nerve. METHODS: The ciliary nerve was obtained from the eyecup after removal of the cornea and intraocular contents following the division of the eyeball at the limbal zone. The explant of the ciliary nerve was cultured with DMEM medium containing nerve growth factor in an incubator with a 5% CO2 atmosphere. The cultured ciliary nerve was examined with phase contrast microscopy at 35 days after culture and stained in the culture dish with 1% methylene blue. The cultured ciliary nerve was also examined with transmission electron microscope. RESULTS: The phase contrast microscopy showed monolayered Schwann cells and cells with thin cytoplasmic processes. The ultrastructure showed myelinated nerve fiber, unmyelinated nerve fiber and Schwann cells entrapped in the nerve fiber. The axoplasm of the myelinated nerve fiber showed the degeneration of microorganelles whereas the unmyelinated nerve fiber showed well preserved microorganelles such as neurofilaments and mitochondria within the axoplasm. CONCLUSIONS: These findings suggest that the axoplasm of the unmyelinated nerve fiber under these culture conditions is relatively better preserved than that of the myelinated nerve fiber probably due to the absence of the myelin sheath. Further study will be required to investigate whether the myelin sheath of the ciliary nerve derived from peripheral neuropathy may affect the functional change of the anterior segment of the eye.