Representative DWI (A and C) and corresponding permeability maps (B and D) of coronal sections of rat brains.

<p>Images shown are from two different groups: A and B from group 1 (scanned at 3 h, n = 8) and C and D from group 2 (studied at 48 h, n = 8). DWI images were used to calculate ADC maps and generate tissue signature maps shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0006597#pone-0006597-g005" target="_blank">Fig. 5A and 5B</a>. Areas of the subcortex and cerebral cortex are demarcated in A and C.</p

Analysis of correlations between BBB permeability and the ADC values in cerebral cortex and subcortex.

<p>Color-coded K_i-ADC maps (A and B) show the three main populations of pixels with different K_i and ADC values for both time points. Quantitative changes of each area over time are presented in panels C and D. Based on the abnormality of ADC values and the BBB permeability; we have recognized three different areas in the ipsilateral side. These areas are labeled as tissue signatures corresponding to different pathophysiology in the evolution of lesion. Each tissue signature is represented by a different color at two different time points, 3 and 48 h of reperfusion. *p<0.05 and **p<0.01 with respect to 3 h.</p

Proposed model showing possible transitions between different states of tissue injury during the progression of ischemic stroke.

<p>Cytotoxic edema is characterized by low ADC values with preserved BBB function (normal K_i), while vasogenic edema is identified by high K_i values. The core of the infarct display high K_i and low ADC values (a mixture of cytotoxic and vasogenic edema). Based on data from the merged ADC+K_i maps (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0006597#pone-0006597-g005" target="_blank">Fig. 5</a>), the main transition occurs from areas with cytotoxic edema to areas with both cytotoxic and vasogenic edema (core of the infarct), which is depicted with a thicker arrow in the schematic.</p

Scatterplots and fit lines showing the correlations between ADC and K_i for the ipsilateral side of cerebral cortex (A and B) and subcortex (C and D) at 3 and 48 h of reperfusion following 2 h of MCAO in the rat.

<p>Scatterplots and fit lines showing the correlations between ADC and K_i for the ipsilateral side of cerebral cortex (A and B) and subcortex (C and D) at 3 and 48 h of reperfusion following 2 h of MCAO in the rat.</p

Figure 3

<p>A. Changes in the area with hypointensive ADC at 3 and 48 h of reperfusion. Significant increases in areas with ADC abnormalities were found between 3 and 48 h in the cerebral cortex. Brain damage observed at 48 h in ADC maps (B) was confirmed histologically using TTC staining (C). Areas of the subcortex and cerebral cortex are demarcated in panels B and C.</p

Secondary screening of neuroprotective compounds.

<p>Compounds identified through high-throughput screening were administered at 0.1 (white), 1 (light gray), 10 (dark gray), and 100 µM (black) at reoxygenation after 2 hours OGD. Twenty-four hours later, cells survival was measured by TUNEL assay and compared to DMSO vehicle-treated neurons. Compounds providing at least 2-fold increased neuroprotection over vehicle were further investigated. MIA, mianserine hydrochloride, ISO, isoxsuprine hydrochloride, MER, meropenem, MEC, meclofenamic acid, ETI, etilifrine hydrochloride, HAL, haloperidol, MOX, moxonidine, CHL, chlorphenesin carbamate, PRO, prothionamide, EPI, epitiostanol.</p

Dose optimization and time course of administration of neuroprotective compounds.

<p>A. Dose response of compounds administered at reoxygenation after 2(ISO) and etilifrine hydrochloride (ETI) and 200 µM for chlorphenesin carbamate (CHL). Isoxsuprine was significantly more protective at 1 nM compared to 0.01, 0.1, and 100 nM (*, <i>p</i><0.01). Etilifrine was significantly more protective at 1 nM compared to 0.01 and 0.1 nM (*, <i>p</i><0.05). Chlorphenesin carbamate was significantly more neuroprotective at 200 µM compared to all other doses (*, <i>p</i><0.05). B. Time course of administration of compounds at the optimal dose at 0, 15, 30, and 60 minutes after reoxygenation onset. Isoxsuprine and chlorphenesin carbamate demonstrated no decrease in neuroprotection when administered up to 60 minutes after reoxygenation onset. Neuroprotection by etilifrine significantly decreased when administered at 60 minutes versus time 0 (*, <i>p</i><0.01).</p

Neuroprotection by isoxsuprine hydrochloride in an animal stroke model.

<p>A. Representative TTC-stained brain sections showing differences in infarction between animals receiving vehicle or isoxsuprine hydrochloride. B. Effect of isoxsuprine hydrochloride on infarct volume. Isoxsuprine hydrochloride (1 mg/kg, IV) given at the onset of reperfusion after a 90-minute MCAO significantly reduced infarct volume compared to vehicle (137±18 mm³ versus 279±25 mm³), <i>p</i><0.001. Closed circles, vehicle, closed squares, isoxsuprine hydrochloride, n = 7 animals for each group.</p

Neuroprotective compounds identified through high-throughput screening of the Prestwick Chemical Library.

1<p>Compounds previously investigated in models of cerebral ischemia are italicized.</p