FIGURE 4.

SPARC expression is upregulated in cortical microglia and astrocytes 72 h following middle cerebral artery occlusion (MCAO). (A) Immunofluorescence labeling for SPARC, IBA-1, and GFAP shows that SPARC is expressed predominantly in microglia in control (contralateral cortex; top panel) but is increased in both microglia and reactive astrocytes 72 h following MCAO (bottom panel) in the peri-infarct region. The peri-infarct region was defined as the region surrounding the infarct core. (B) SPARC is upregulated in a similar proportion of IBA+ microglia and GFAP+ astrocytes following MCAO [2-tailed, 2-sample t-test; p = 0.605, n = 8]. (C) Representative immunoblots showing changes in SPARC expression in the ipsilateral cortex at 48 h, 72 h and 15 days post MCAO compared to Sham treated animals. SPARC levels were significantly increased at 72 h post MCAO but decreased by 15 days [2-tailed, 2-sample t-test; p = 0.040, n = 3)].