Blood-brain barrier (BBB) disruption and consequent edema formation contributes to the

Blood-brain barrier (BBB) disruption and consequent edema formation contributes to the development of early brain injury following subarachnoid hemorrhage (SAH). neurological functions. Decreased brain expressions of phosphorylated PDGFR-α c-Src JNK and c-Jun; as well as reduced MMP-9 activities were found in treated animals. PDGFR-α inhibition preserved BBB integrity following experimental SAH; however the protective mechanisms remain EX 527 to be elucidated. Targeting PDGFR-α signaling may be an advantageous strategy to ameliorate early brain injury following SAH. forty-four male Sprague-Dawley rats (weighing 280-350g; Harlan Indianapolis IN) were subjected to either sham operation (n=33) or SAH induction (n=111). All animals were housed in a light- and temperature-controlled environment with free access to food and water. SAH modeling and study design The HMOX1 endovascular perforation SAH model was performed as previously described (Schwartz et al. 2000). Briefly anesthetized rats were intubated and artificially ventilated with 3% isoflurane in a 70/30% medical air/oxygen gas mixture. With the animal in a supine position the rodent’s EX 527 left external carotid artery (ECA) was exposed and a sharpened 4-0 monofilament EX 527 nylon suture was inserted into the ECA. The suture was gently advanced into the internal carotid artery (ICA) until resistance was felt by the bifurcation of the anterior (ACA) and middle cerebral artery (MCA). Endovascular perforation was achieved by further advancing the suture 3mm past the point of resistance followed by immediate withdrawal of the suture to allow reperfusion of the ICA. The sham operation consisted of suture insertion; however no vessel perforation was performed. The PDGFR inhibitor imatinib mesylate (Gleevec? Novartis) was dissolved in PBS and administered intraperitoeally in two different dosages (40 or 120mg/kg) 1 hour after SAH induction. Vehicle animals received PBS only. One hundred and ten rats survived the EX 527 surgery and passed all inclusion criteria (see below). These animals were randomly divided into the following groups: sham-operated (Sham; n=33) and SAH animals receiving either PBS administration (Vehicle; n=38) 40 imatinib (Imatinib-40mg; n=6) or 120mg/kg imatinib (Imatinib-120mg; n=33). Evans blue extravasation Western blot immunoprecipitation and gelatin zymography assays were conducted at 24 hours; neurological function body weight loss and brain edema were evaluated at 24 and 72 hours after surgery. SAH grading At the time of euthanasia a photograph of the rat’s brain base was taken and divided into 6 predetermined areas as previously described (Sugawara et al. 2008). Each area was given a score from 0 to 3 depending on the amount of blood present. The total SAH grade was calculated by adding all area scores (maximum SAH grade=18). Animals presenting with mild SAHs (grade<9) or with coexisting subdural or epidural hemorrhages EX 527 were excluded EX 527 from this study. Neurological function testing Immediately prior to euthanasia neurological function was evaluated in a blinded fashion by means of the modified Garcia score (Garcia et al. 1995). This composite sensorimotor assessment consists of 6 sub-tests evaluating the animal’s spontaneous activity its reaction to side stroking and vibrissae touch as well as limb symmetry forelimb walking and climbing ability. Each sub-test received a score between 0 and 3 and the sum of all sub-tests was calculated to determine neurological function (maximal score of 18 for best test performance). Blood-brain barrier permeability Permeability of the BBB was evaluated by means of Evans blue extravasation assays as previously described (Uyama et al. 1988). Briefly anesthetized rats were subjected to Evans blue dye injection (2%; 5ml/kg) into the left femoral vein at 23 hours after SAH induction or sham surgery. Deeply anesthetized rats were euthanized by transcardiac PBS perfusion and brain specimens were removed and separated into ipsi- and contralateral brain hemispheres. The amount of extravasated albumin-bound Evans blue dye was measured spectrophotometrically (Genesis 10uv Scanning; Thermo Electron Corporation Madison WI) at 615nm. Brain water content Bain edema (brain water content) was evaluated via.