Impairments of tight junctions are involved in D-galactose-induced brain aging.

Impairments of tight junctions are implicated in the course of various age-related neurodegenerative disorders. Chronic injection of D-galactose can cause a progressive deterioration in learning and memory capacity and serve as an animal model of aging. To investigate the involvement of tight junctions in this model, oxidative stress biomarkers, expression and ultrastructure of tight junctions, and the permeability of blood-brain barrier were examined in the hippocampus of the mice, which received an injection of D-galactose for 6 weeks. D-Galactose-injected mice showed impaired antioxidant systems, decreased levels of tight junction proteins, and ultrastructural pathological changes of tight junctions, accompanied by increased blood-brain barrier permeability in the hippocampus. These results show that impairments in tight junctions are involved in D-galactose-induced brain aging.