Expression of osteopontin in the central nervous system of BALB/c mice

Abstract

Osteopontin (OPN) is an integrin and calcium-binding phosphoprotein that is produced by mineralized tissue cells, many epithelial cells, and activated immune system cells The aim of this study was to examine the expression and cellular localization of OPN in the central nervous system, including the cerebrum, cerebellum and spinal cord. Female BALB/c mice (25g, 8 weeks oId) tissues were collected and used for Western blot analysis and immunohistochemistry. Western blot analysis showed that OPN was detected 55- (upper) and 29-kDa (lower) in the central nervous system. OPN immunoreactivity was low in the cerebrum: moderate in the cerebellum; and high in the spinal cord. Immunohistochemical study showed that the expression of OPN was immunostained neuron and astrocytes in central nervous system. In the olfactory bulb, OPN immunoreactivity was found in mitral cell layer and glomerular layer, but not in external plexiform layer. In the hippocampus, OPN expression was observed in the peripheral area but not CA regions. In the cerebellum, OPN immunoreactivity was found in purkinje cell layer and molecular layer, bul not in granule cell layer. In spinal cord, OPN immunoreactivity was weakly found in neuron and some astrocyte. The present study is the first to report that OPN is variably expressed in CNS tissue. This finding suggests that OPN may play an important role in neurons and astrocytes in the normal central nervous system. Further study is needed to elucidate the functional role of OPN in central nervous system.