Myelin Sheath Injury in Kaolin-Induced Hydrocephalus: A Light and Electron Microscopy Study

Background: In hydrocephalus, the impairment of cognitive and motor functions is thought to be partly due to injury to the myelin sheath of axons in the central nervous system. The exact nature of this injury is not completely understood. Methods: We induced hydrocephalus in 3-week-old rats with an intracisternal injection of kaolin suspension (0.04 ml of 200 mg/ml) and examined paraffin and ultrathin sections of the subcortical white matter from coronal slices of the cerebrum obtained at the level of the optic chiasm after sacrifice at weekly intervals for 4 weeks. Results: Over time, there was a progression of injury to the myelin sheath consisting of attenuation, lamella separation and accumulation of myelin debris, focal degeneration, and the appearance of casts and loops. Conclusion: The results suggest that myelin injury in kaolin-induced hydrocephalus progresses with the duration and severity of ventriculomegaly. (C) 2016 S. Karger AG, Basel