Endogenous expression of osteopontin in the brain in normal and hypoxia-ischemia-injured mice. In uninjured mice, the expression of endogenous osteopontin (OPN) during development was analyzed by Western blotting using the whole-brain homogenates at postnatal day 3 (P3), P9, P21 and P60. (A) A representative Western blot. (B) The quantification of the Western blot analysis by measuring the density of the immunoreactive bands (n = 3). (C) The mRNA expression of endogenous OPN in the left hemisphere of uninjured control mice (Cont) and the contralateral (Contra) and ipsilateral (Ipsi) hemispheres after hypoxia-ischemia (HI) injury (n = 6 to 8). The data are presented as the ratios between OPN and reference gene (18S) mRNA expression. No changes in the 18S mRNA expression were observed in the brain after HI-induced injury. Data presented are the mean ± SD. *P < 0.05; **P < 0.01; ***P < 0.001.