Reactive oxygen species induce neurite degeneration before induction of cell death.

Reactive oxygen species (ROS) induce neuronal cell death in a time- and concentration-dependent manner. Treatment of cultured cells with a low concentration of hydrogen peroxide induces neurite degeneration, but not cell death. Neurites (axons and dendrites) are vulnerable to ROS. Neurite degeneration (shrinkage, accumulation, and fragmentation) has been found in neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. However, the mechanism of ROS-related neurite degeneration is not fully understood. Many studies have demonstrated the relationship between mitochondrial dysfunction and microtubule destabilization. These dysfunctions are deeply related to changes in calcium homeostasis and ROS production in neurites. Treatment with antioxidant substances, such as vitamin E, prevents neurite degeneration in cultured cells. This review describes the possibility that ROS induces neurite degeneration before the induction of cell death.