Age‑dependent alterations in the immunoreactivity of macrophage inflammatory protein‑3α and its receptor CCR6 in the gerbil hippocampus.

Neuroinflammation is a primary characteristic of the aging brain. During normal aging, macrophage inflammatory protein‑3α (MIP‑3α) and its receptor C‑C chemokine receptor type 6 (CCR6) serve pivotal roles in the neuroinflammatory process in the brain. The aim of the present study was to investigate age‑dependent alterations in the immunoreactivity of MIP‑3α and CCR6 in the gerbil hippocampus at postnatal month (PM) 1, 6, 12 and 24 via immunohistochemistry. In the PM 1 group, both MIP‑3α and CCR6 immunoreactivity were observed primarily in the stratum pyramidale in the hippocampus proper and in the granule cell layer in the dentate gyrus. In the PM 6 and PM 12 groups, MIP‑3α in the stratum pyramidale and granule cell layer was decreased compared with the PM 1 group, and CCR6 immunoreactivity in both layers was faint. In the PM 24 group, MIP‑3α expression in the stratum pyramidale and granule cell layer was higher than that in the PM 1 group, and CCR6 immunoreactivity in both layers was increased compared with the PM 12 group; however, it was decreased compared with the PM 1 group. In conclusion, MIP‑3α and CCR6 immunoreactivity were altered in the hippocampus during normal aging. The results of the current study suggested that age‑dependent alterations of MIP‑3α and CCR6 may be associated with age‑related neuroinflammation in the hippocampus.