FIG. 4.

OPN protein distribution changes within OB after mFPI. (A) Imaging of sham cases shows OPN (green) localized to presumptive tufted neurons at the border of GL and EPL, as well as mitral neurons in the ML (arrows). Post-injury OPN signal revealed neuronal increase, modest at 3 days and more robust in cell bodies and primary dendrites at 7 days. At 21 days OPN, intensity appeared to shift toward that of 3-day signal. Inset shows CCK⁺ terminals (red) of tufted neurons (arrows) surrounding OPN⁺ mitral cell bodies (green). (B) Double label with OPN (green) + GFAP (red) at 3 days and OPN (green) + IBA1 (red) at 7 days failed to show detectable colocalization of signal in reactive glial cells of the deafferented OB. Bar = 50 μm. n = 3–4/group. CCK, cholecystokinin; EPL, external plexiform layer; GFAP, glial fibrillary acidic protein; GL, glomerular layer; IBA1, ionized calcium-binding adaptor protein 1; mFPI, mild fluid percussion injury; ML, mitral cell layer; OPN, osteopontin.