Stress-induced microglial activation may facilitate the progression of neurodegenerative disorders.

Microglial activation has been associated with various clinical disorders. In particular, activated microglia have been reported in various brain regions, including the hippocampus, substantia nigra, striatum, and cerebral cortex, in which significant neurodegeneration occurs in various neurodegenerative disorders. Our previous study demonstrated that acute stress, restraint combined with water immersion, substantially induces massive microglial activation in the brain, particularly in the hippocampus, hypothalamus, thalamus, and periaquaductal gray. Furthermore, several studies have also demonstrated that exposure of animals to stress induces microglial activation in the hippocampus and striatum, and also induces the proliferation of microglial cells. Although stress has been shown to contribute to the neurodegenerative changes in the brain, the precise mechanism of this effect remains to be elucidated. Here, we propose that stress-induced microglial activation may be involved in the progression of neurodegenerative changes. Reduction of stress-induced microglial activation may prevent further progression of neurodegenerative disorders.