Diabetes Differentially Alters Glial Cells in Different Brain Regions

The chronic metabolic condition of hyperglycemia in type-2 diabetics is known to cause various neurological disorders and compromise recovery from brain insults. Previously, we reported a delayed and reduced glial cell response and a greater neuronal cell death in different brain regions of diabetic, db/db, mice following cerebral hypoxic- ischemic (HI) injury. In this study, we explored the changes in baseline activation of astrocytes and microglia and its impact on vascular permeability in different brain regions. The number of activated astrocytes (GFAP) and microglia/macrophage (Iba-1) in the motor cortex, caudate and hippocampal (CA3) regions of 12-week old, type-2 diabetic db/db and non-diabetic db/+ mice were quantitated. Immunofluorescence double staining for the leakage of serum IgG and cerebral blood vessel and occludin staining for the tight junctional (TJs) protein in the blood brain barrier (BBB) were investigated. Results indicated significant differences in activation of glial cells in the cortex and caudate along with increased vessel permeability in diabetic mice. The study suggests that a constant activation of glial cells in the diabetic brain may be the cause of impaired inflammatory response and/or degenerating cerebral blood vessels which contribute to neuronal cell death upon CNS injury.