Inhibition of Rho kinase by hydroxyfasudil attenuates brain edema after subarachnoid hemorrhage in rats

Department of Physiology and Pharmacology, Loma Linda University, 11234 Anderson Street, Loma Linda, CA 92354, USA.
Neurochemistry International (Impact Factor: 3.09). 02/2012; 60(3):327-33. DOI: 10.1016/j.neuint.2011.12.014
Source: PubMed


The blood-brain barrier (BBB) disruption and brain edema are important pathophysiologies of early brain injury after subarachnoid hemorrhage (SAH). This study is to evaluate whether Rho kinase (Rock) enhances BBB permeability via disruption of tight junction proteins during early brain injury. Adult male rats were assigned to five groups; Sham-operated, SAH treated with saline, a Rock inhibitor hydroxyfasudil (HF) (10 mg/kg) treatment at 0.5 h after SAH, HF treatment at 0.5 and 6 h (10 mg/kg, each) after SAH, and another Rock inhibitor Y27632 (10 mg/kg) treatment at 0.5 h after SAH. The perforation model of SAH was performed and neurological score and brain water content were evaluated 24 and 72 h after surgery. Evans blue extravasation, Rock activity assay, and western blotting analyses were evaluated 24 h after surgery. Treatment of HF significantly improved neurological scores 24 h after SAH. Single treatment with HF and Y27632, and two treatments with HF reduced brain water content in the ipsilateral hemisphere. HF reduced Evans blue extravasation in the ipsilateral hemisphere after SAH. Rock activity increased 24 h after SAH, and HF reversed the activity. SAH significantly decreased the levels of tight junction proteins, occludin and zonula occludens-1 (ZO-1), and HF preserved the levels of occluding and ZO-1 in ipsilateral hemisphere. In conclusion, HF attenuated BBB permeability after SAH, possibly by protection of tight junction proteins.

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    • "CLDN5 knockout mice presented increased BBB permeability [13]; on the contrary, inhibiting decreased expression of CLDN5 has been shown to reduce brain edema and hemorrhagic transformation [14]. The expressions of ZO- 1 and OCLN were significantly decreased after subarachnoid hemorrhage (SAH) [15], and degrading ZO-1 and OCLN in endothelial tight junction can facilitate capillary leakage, which is responsible for the increase in BBB permeability after SAH [16]. Increased BBB permeability after ICH has been noted in parallel with edema formation and BBB disruption leading to vasogenic edema [17]. "
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    ABSTRACT: Brain injury after intracranial hemorrhage (ICH) results in significant morbidity and mortality. Blood brain barrier (BBB) disruption is a hallmark of ICH-induced brain injury; however, data mirroring BBB disruption in human ICH are scarce. The aim of this study was to assess the significance of circulating biomarkers in evaluating BBB disruption after ICH. Twenty-two patients with ICH were recruited in this study. Concentrations of the tight junction proteins (TJs) Claudin-5 (CLDN5), Occludin (OCLN), and zonula occludens 1 (ZO-1) and vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) were measured by using enzyme-linked immunosorbent assay in serum and cerebrospinal fluid (CSF) samples obtained from patients with ICH. The white blood cell (WBC) count in blood and CSF, albumin (ALB) levels in the CSF ( ALB CSF ), and the BBB ratio were significantly higher in the ICH than in controls ( p < 0.05 ). Significantly higher levels of CLDN5, OCLN, ZO-1, MMP-9, and VEGF in CSF were observed in the ICH group; these biomarkers were also positively associated with BBB ratio ( p < 0.05 ). Our data revealed that circulating TJs could be considered the potential biomarkers reflecting the integrity of the BBB in ICH.
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    • "However , this value was markedly increased on day 5 after bleeding. In agreement with these observations, RhoA and ROCK mRNAs are upregulated in the basilar artery of SAH rat models [30] [35]. In summary, we show here that inhibition of LTCCs, PLC, SR refilling and ROCK selectively and significantly reduces the potentiation of the sustained component of the depolarization-evoked contraction observed on day 5 after SAH. "
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    ABSTRACT: We have previously described that L-type Ca(2+) channels (LTCCs) activation and metabotropic Ca(2+) release from the sarcoplasmic reticulum (SR) regulate RhoA/Rho kinase (ROCK) activity and sustained arterial contraction. We have investigated whether this signaling pathway can be altered in a new experimental model of subarachnoid hemorrhage (SAH). For this purpose, arterial reactivity was evaluated on days 1 to 5 after surgery. A significant increase of basal tone, measured 4 and 60minutes after normalization, was observed on day 5 after SAH and at 60minutes on days 2 and 3 after SAH. This phenomenon was suppressed with LTCCs and ROCK inhibitors. We have also studied arterial rings vasoreactivity in response to high K(+) solutions. Interestingly, there were no significant differences in the phasic component of the high K(+)-induced contraction between sham and SAH groups, whereas a significant increase in the sustained contraction was observed on day 5 after SAH. This latter component was sensitive to fasudil, and selectively reduced by low nifedipine concentration, and phospholipase C and SR-ATPase inhibitors. Therefore, our data suggest that the metabotropic function of LTCCs is potentiated in SAH. Our results could provide a new strategy to optimize the pharmacological treatment of this pathological process. Copyright © 2015. Published by Elsevier Inc.
    No preview · Article · Apr 2015 · Vascular Pharmacology
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    • "A total of 25 adult male Sprague-Dawley rats (Harlan, Indianapolis, IN) weighing 260–320 g were used for the study. The endovascular perforation model of SAH was performed as previously described [5,6]. Briefly, rats were anesthetized, intubated and kept on artificial ventilation during surgery. "
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    ABSTRACT: Chronic communicating hydrocephalus is a significant health problem affecting up to 20% of survivors of spontaneous subarachnoid hemorrhage (SAH). The development of new treatment strategies is hampered by the lack of well characterized disease models. This study investigated the incidence of chronic hydrocephalus by evaluating the temporal profile of intracranial pressure (ICP) elevation after SAH, induced by endovascular perforation in rats. Twenty-five adult male Sprague-Dawley rats (260-320g) were subjected to either endovascular perforation or sham surgery. Five animals died after SAH induction. At 7, 14 and 21 days after surgery ICP was measured by stereotaxic puncture of the cisterna magna in SAH (n=10) and SHAM (n=10) animals. On day 21 T-maze test was performed and the number of alterations and latency to decision was recorded. On day 23, samples were processed for histological analyses. The relative ventricle area was evaluated in coronal Nissl stained sections. On day 7 after surgery all animals showed normal ICP. The absolute ICP values were significantly higher in SAH compared to SHAM animals on day 21 (8.26±4.53 mmHg versus 4.38±0.95 mmHg) but not on day 14. Observing an ICP of 10mmHg as cut-off, 3 animals showed elevated ICP on day 14 and another animal on day 21. The overall incidence of ICP elevation was 40% in SAH animals. On day 21, results of T-maze testing were significantly correlated with ICP values, i.e. animals with elevated ICP showed a lower number of alterations and a delayed decision. Histology yielded a significantly higher (3.59 fold increased) relative ventricle area in SAH animals with ICP elevation compared to SAH animals without ICP elevation. In conclusion, the current study shows that experimental SAH leads to chronic hydrocephalus, which is associated with ICP elevation, behavioral alterations and ventricular dilation in about 40% of SAH animals.
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