Alteration of parvalbumin expression and perineuronal nets formation in the cerebral cortex of aged mice

• Published in: Molecular and cellular neuroscience 2019-03, Vol.95, p.31-42
• Main Authors: Ueno, Hiroshi, Fujii, Kazuki, Takao, Keizo, Suemitsu, Shunsuke, Murakami, Shinji, Kitamura, Naoya, Wani, Kenta, Matsumoto, Yosuke, Okamoto, Motoi, Ishihara, Takeshi
• Format: Article
• Language: English
• Subjects: Aging; Cerebral cortex; Mouse; Parvalbumin; Perineuronal nets; Retrosplenial cortex
• ISSN: 1044-7431; 1095-9327
• DOI: 10.1016/j.mcn.2018.12.008

Aging is associated with decline in cognitive function, but the underlying mechanisms have not been elucidated. Normal activity of pyramidal cells and parvalbumin-expressing interneurons (PV neurons) is essential for cognitive function. PV neurons participate in the regulation of pyramidal-cell firing. Abnormal function of PV neurons may occur with aging. We analyzed the density and the percentage of PV neurons surrounded by perineuronal nets (PNNs) in the entire cortex of adult (3-month-old) and aged (24-month-old) mice. PNNs are extracellular matrix molecules that cover PV neurons and control synaptic plasticity. PV-neuron density decreased in some cortical areas of aged compared to adult mice. In particular, in the retrosplenial granular cortex (RSG) of aged mice, pyramidal cells expressed PV protein at high levels. This study suggests that the RSG of aged mice is in an abnormal activated state. RSG function abnormality may be part of the cognitive decline mechanism. •PV-neuron density decreased in several regions of the aged mouse cortex.•WFA-positive PNN density remained unchanged in most regions of the aged mouse cortex.•PV immunostaining of pyramidal cells significantly increased in the aged RSG.•VGLUT1-positive synapse density increased in the RSG of aged mice.