Ischemia induces BDNF mRNA expression by neuronal and endothelial cells in the ipsilateral striatum.

<p><b><i>A,</i></b> PCR analysis of BDNF expression in the ischemic striatum 1 week after MCAo. Examples of contralateral (CL) and ipsilateral (IPSI) striata from 2 animals are shown. Low panel shows the quantification of BDNF expression in the ischemic striatum. <b><i>B</i></b>, <i>In situ</i> hybridization revealed an upregulation of BDNF mRNA in rounded cells in the ipsilateral striatum 1 week post-ischemia (middle). Little or no BDNF mRNA was found in these cells 2 weeks post-ischemia (right). <b><i>C–H</i></b>, High magnification images revealed that BDNF mRNA was expressed in NeuN⁺ striatal neurons (arrow) <b>(</b><b><i>C</i></b><b>)</b> and dextran-Texas Red-filled blood vessels <b>(</b><b><i>D</i></b><b>)</b>. <b><i>E–H</i></b>, No BDNF mRNA was observed in Dcx⁺ neuroblasts (<b><i>E</i></b>), GFAP⁺ astrocytes (<b><i>F</i></b>), Iba1⁺ microglia (<b><i>G</i></b>), or Olig2⁺ oligodendrocytes (<b><i>H</i></b>) in the injured striatum. Arrowheads indicate cells negative for BDNF mRNA and arrows indicate cells positive for BDNF mRNA. Scale bars: <b><i>B</i></b>, 200 µm; <b><i>E</i></b>,<b><i>H</i></b>, 20 µm; <b><i>C</i></b>,<b><i>D</i></b>,<b><i>F</i></b>,<b><i>G</i></b>, 10 µm (CL: contralateral; IPSI: ipsilateral; wk: week; ISH: <i>in situ</i> hybridization).