Rabbit Model Of Subarachnoid Hemorrhage Research Articles

Cranial hyperthermia resulting from decreased parotid gland salivation induced by ischemic degeneration of glossopharyngeal network in subarachnoid hemorrhage

Objective: We speculated that subarachnoid hemorrhage (SAH) induces ischemic lesions in the cranial parasympathetic nerves, which may decrease saliva secretion and lead to hyperthermia. We tested this hypothesis by examining histologic features of parotid glands and glossopharyngeal nerves (GPNs) in a rabbit model of SAH.
 Material and Methods: Rabbits (n = 25) were divided into control (n = 5), sham (n = 5), and SAH (n = 15) groups. Animals in the sham and SAH groups were examined over a 3-week period before sacrifice. Salivation score (SC) was determined by measuring the mean wetted area of an orally inserted cotton ball. Sections of parotid glands and intracranial and intraparotideal branches of the GPNs were stained with hematoxylin and eosin and SAH-induced damage was analyzed by terminal deoxynucleotidyl transferase dUTP nick end labeling of apoptotic cells. Specimens were stereologically examined to determine saliva-filled total vesicle volume (TVV) per cubic meter; vasospasm index (VSI) based on wall/lumen ratio of parotid glands arteries, and degenerated neuron density (DND) of glossopharyngeal ganglia.
 Results: The mean oral temperature was 36.9°C. In the control group, mean values were as follows: SC, 46±8 mm2; DND, 19±4/mm3; VSI, 1.065±0.049; and TVV, (780±1187) × 106/µm3. In the sham group, mean values were as follows: SC, 31±6 mm2; DND, 98±23/mm3; VSI, 1.67±0.32; and TVV, (617±110) × 106/µm3. In the low hyperthermia SAH group, mean values were as follows: SC, 16±5 mm2; DND, 1520±261/mm3; VSI, 2.12±0.21, and TVV, (314±98) × 106/µm3. In the high hypothermia SAH group, mean values were as follows: SC, 9±2 mm2; DND, 3210±912/mm3; VSI, 3.18±0.30; and TVV, (432±99) × 106/µm3.
 Conclusions: Decreased salivary secretion due to secretory gland atrophy originated from ischemia-induced GPN network degeneration at the brainstem, which may be responsible for cranial hyperthermia following SAH.

Tocilizumab Reduces Vasospasms, Neuronal Cell Death, and Microclot Formation in a Rabbit Model of Subarachnoid Hemorrhage.

Early brain injury (EBI), delayed cerebral vasospasm (DCVS), and delayed cerebral ischemia (DCI) are common complications of subarachnoid hemorrhage (SAH). Inflammatory processes in the cerebrospinal fluid (CSF) are one of the causes for such complications. Our aim to study the effects of an IL-6 receptor antagonist (Tocilizumab) examines the occurrence of DCVS, neuronal cell death, and microclot formation in an acute SAH rabbit model. Twenty-nine New Zealand white rabbits were randomized into one of three groups as the SAH, SAH + Tocilizumab, and sham groups. In SAH groups, hemorrhage was induced by extracranial-intracranial arterial blood shunting from the subclavian artery into the cisterna magna under intracranial pressure (ICP) monitoring. In the second group, Tocilizumab was given once intravenously 1h after SAH induction. Digital subtraction angiography was performed, and CSF and blood were sampled before and after (day 3) SAH induction. IL-6 plasma and CSF levels were measured. TUNEL, FJB, NeuN, and caspase-3 immunostaining were used to assess cell apoptosis, neurodegeneration, and neuronal cell death, respectively. Microclot formation was detected by fibrinogen immunostaining. Between baseline and follow-up, there was a significant reduction of angiographic DCVS (p < 0.0001) in the Tocilizumab compared with the SAH group. Tocilizumab treatment resulted in decreased neuronal cell death in the hippocampus (p = 0.006), basal cortex (p = 0.001), and decreased microclot formation (p = 0.02). Tocilizumab reduced DCVS, neuronal cell death, and microclot formation in a rabbit SAH model, and could be a potential treatment to prevent DCVS and DCI in SAH patients.

Tissue kallikrein: A potential serum biomarker to predict delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage

BackgroundDelayed cerebral ischemia (DCI) is a severe complication after aneurysmal subarachnoid hemorrhage (aSAH). Tissue kallikrein (TK), a subgroup of serine proteinases, is an important component of the kallikrein-kinin system. Exogenous TK attenuated cerebral vasospasm in a rabbit model of subarachnoid hemorrhage. We intended to discern association of serum TK levels with aSAH-related DCI. MethodsSerum TK levels were detected in a total of 92 aSAH patients and 92 healthy controls. A multivariate logistic regression model was configured to investigate relationship between TK levels and occurrence of DCI. ResultsTK levels were substantially lower in aSAH patients than in controls. TK levels were strongly correlated with World Federation of Neurological Surgeons (WFNS) score and modified Fisher score. Serum TK, WFNS score and modified Fisher score retained as the three independent predictors for DCI. Under receiver operating characteristic curve, predictive capability of TK levels was in the range of WFNS score and modified Fisher score, as well as TK levels could remarkably improve predictive abilities of WFNS score and modified Fisher score. ConclusionsSerum TK emerges as a potential biomarker for assessment of hemorrhagic severity and prediction of DCI following aSAH.

Systemic and CSF Interleukin-1α Expression in a Rabbit Closed Cranium Subarachnoid Hemorrhage Model: An Exploratory Study.

Background: The inflammatory pathway in cerebrospinal fluid (CSF) leads to delayed cerebral vasospasm (DCVS) and delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH). The role of IL-1α has never been evaluated in a rabbit SAH model. The aim of our study is to analyze systemic and CSF changes of IL-1α, and to evaluate potential associations with the onset of DCVS in a rabbit closed cranium SAH model. Methods: 17 New Zealand white rabbits were randomized into two groups, SAH (n = 12) and sham (n = 5). In the first group, SAH was induced by extracranial-intracranial shunting from the subclavian artery into the cerebral cistern of magna under intracranial pressure (ICP) monitoring. The sham group served as a control. The CSF and blood samples for IL-1α measurement were taken at day zero before SAH induction and at day three. Results: There was a significant increase of ICP (p = 0.00009) and a decrease of cerebral perfusion pressure (CPP) (p = 0.00089) during SAH induction. At follow up, there was a significant increase of systemic IL-1α in the SAH as compared with the sham group (p = 0.042). There was no statistically significant difference in the CSF values in both groups. The CSF IL-1α values showed a correlation trend of DCVS. Conclusions: Systemic IL-1α levels are elevated after SAH induction in a rabbit SAH model.

CT perfusion imaging of cerebral microcirculatory changes following subarachnoid hemorrhage in rabbits: Specific role of endothelin-1 receptor antagonist

BackgroundCerebral vasospasm may lead to delayed ischemic neurological deficits following subarachnoid hemorrhage (SAH). Endothelin (ET-1) is an important factor participating in cerebral vasospasm underlying SAH. We used a specific endothelin receptor antagonist, BQ123 to assess the specific role of endothelin-1 receptor antagonist in cerebral vasospasm in a rabbit model of SAH by examining plasma ET-1 levels and the principal CT perfusion (CTP) parameters pertinent to the hemodynamic status of microcirculation following SAH. Methods102 male New Zealand white rabbits were divided into control, SAH and SAH + BQ123 intervention group (BQ123 group). Rabbit SAH model was established by double hemorrhage injection of autologous blood into the cisterna magna; Aquilion ONE was used to collect cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) which were used to evaluate cerebral microcirculation hemodynamics; Elisa was used to assess plasma ET-1 levels. Data were collected on days 1, 4, 7 and 14 following SAH, respectively. ResultsCompared with the control group, the CBF in the SAH group was significantly lower, while the MTT was significantly higher. The CBF decreased on the 4th day and reached the lowest on the 7th day. The MTT began to rise on the 4th day and peaked on the 7th day. While in the BQ123 intervention group, the CBF significantly increased while the MTT significantly decreased on the 1st and the 4th days, respectively. Compared with SAH group, plasma ET-1 levels in BQ123 group significantly increased on the earlier (1st and 4th days) but not later days (between the 7th and 14th days). In addition, the inflammatory infiltration of brain tissues in rabbits treated with BQ123 post-SAH was significantly reduced compared with SAH group. ConclusionCTP can quantify the therapeutic effect of BQ123 after SAH; Selective blockade of ET-1 endothelin receptor, BQ123 significantly improved microcirculatory perfusion along with a reduction in resultant vasogenic inflammatory responses. The effect of BQ123 on the cerebral microcirculation was lobe dependent.

Abstract TP410: Microcirculatory Impairment is Caused by Independent Mechanisms From Major Arterial Spasm Both in the Acute and Chronic Phase After Experimental SAH

Background &amp; Objectives: The mechanism of microcirculatory disturbance following subarachnoid hemorrhage (SAH) remains to be elucidated. In this study, we investigated the correlation between the cerebral microcirculatory change and the time-dependent alteration of major arterial vasoconstriction after SAH using rabbit SAH model. Methods: CT angiography and perfusion were repeated at 0, 1, 6, 24, 48 hours after first hemorrhage for acute changes observation group (n=8), and on days 0, 3, 5, 7 for chronic changes observation group (n=8) using multi-detector raw CT. Regional cerebral blood flow (rCBF), cerebral blood volume (CBV), mean transit time (MTT) and basilar artery (BA) diameter were calculated at each time point. Results: In acute group, immediately after hemorrhage, BA narrowed, both CBV and rCBF were decreased and MTT was increased, transiently. After 6 hours, BA narrowed again and both CBV and rCBF were increased progressively. MTT restored over 24 hours. In chronic group, BA narrowing reached a peak on day 5 and restored after day 7. Both CBV and rCBF were persistently decreased after day 3, while MTT was increased after day 5. In both groups, no significant changes were observed in CBV, rCBF and MTT between in BA territory and other territory. Conclusions: Delayed cerebral ischemia may be caused by the microcirculatory disturbance which is regulated by independent mechanisms from major arterial vasospasm both in the acute and chronic phase after SAH in rabbit model.

The Vasorelaxant and Neuroprotective Effects of Mildronate in A Rabbit Subarachnoid Hemorrhage Model.

To investigate the effects of an anti-ischemic agent, mildronate, on subarachnoid hemorrhage-induced vasospasm. Rabbits were randomly divided into four groups: control, subarachnoid hemorrhage (SAH), vehicle, and mildronate (n=8 animals per group). In the treatment group, 200 mg/kg of mildronate were intraperitoneally administered 5 minutes after the procedure and continued for 3 days as daily administrations of the same dose. At the end of the third day, the cerebrum, cerebellum, and brain stem were perfused, fixated, and removed for histopathological examination. Tissues were examined for arterial wall thickness, luminal area, and hippocampal neuronal degeneration. Mildronate group showed significantly increased luminal area and reduced wall thickness of the basilar artery compared with the subarachnoid hemorrhage group. In addition, the hippocampal cell degeneration score was significantly lower in the mildronate group than in the SAH and vehicle groups. These results show that mildronate exerts protective effects against SAH-induced vasospasm and secondary neural injury.

Protective effects of atorvastatin on cerebral vessel autoregulation in an experimental rabbit model of subarachnoid hemorrhage.

The aim of the present study was to assess the therapeutic effects of atorvastatin on cerebral vessel autoregulation and to explore the underlying mechanisms in a rabbit model of subarachnoid hemorrhage (SAH). A total of 48 healthy male New Zealand rabbits (weight, 2–2.5 kg) were randomly allocated into SAH, Sham or SAH + atorvastatin groups (n=16/group). The Sham group received 20 mg/kg/d saline solution, whereas 20 mg/kg/d atorvastatin was administered to rabbits in the SAH + atorvastatin group following SAH induction. Changes in diameter, perimeter and basilar artery (BA) area were assessed and expression levels of the vasoactive molecules endothelin-1 (ET-1), von Willebrand factor (vWF) and thrombomodulin (TM) were measured. Neuronal apoptosis was analyzed 72 h following SAH by terminal deoxynucleotidyl-transferase-mediated dUTP nick-end labeling (TUNEL) staining. The mortality rate in the SAH group was 18.75, 25% in the SAH + atorvastatin treated group and 0% in the Sham group (n=16/group). The neurological score in the SAH + atorvastatin group was 1.75±0.68, which was significantly higher compared with the Sham group (0.38±0.49; P<0.05). The BA area in the SAH + atorvastatin group (89.6±9.11) was significantly lower compared with the SAH group (115.4±11.0; P<0.01). The present study demonstrated that SAH induction resulted in a significant increase in the diameter, perimeter and cross-sectional area of the BA in the SAH + atorvastatin group. Administration of atorvastatin may significantly downregulate the expression levels of ET-1, vWF and TM (all P<0.01) vs. sham and SAH groups. TUNEL staining demonstrated that neuronal apoptosis was remarkably reduced in the hippocampus of SAH rabbits following treatment with atorvastatin (P<0.05). Atorvastatin treatment may alleviate cerebral vasospasm and mediate structural and functional remodeling of vascular endothelial cells, in addition to promoting anti-apoptotic signaling. These results provided supporting evidence for the use of atorvastatin as an effective and well-tolerated treatment for SAH in various clinical settings and may protect the autoregulation of cerebral vessels.

Recombinant neuroglobin ameliorates early brain injury after subarachnoid hemorrhage via inhibiting the activation of mitochondria apoptotic pathway

Neuroglobin (Ngb) overexpression is considered as an intrinsic neuroprotective response. Therefore, exogenous Ngb increased in brain tissues has become a promising therapeutic strategy for neurological diseases. Previous studies demonstrated that transactivator of transcription (TAT) protein transduction domain was able to mediate synthetic Ngb entrance into neurons, and then protected brain from hypoxia-ischemic injury. However, the role of recombinant Ngb on early brain injury following subarachnoid hemorrhage (SAH) has not been elucidated. The objectives of this study were to investigate the expression of endogenous Ngb in brain using a rabbit model of SAH, and to verify whether TAT-Ngb fusion protein could be delivered into brain parenchyma, as well as to explore the neuroprotective effect of Ngb and its possible mechanisms. We found that Ngb expressions were up regulated in the transcript and protein levels in a similar time dependent manner after SAH as compared to the sham group. Moreover, TAT-Ngb fusion protein was successfully generated and transferred into brain neurons. Compared with the saline- and Ngb-treated group, neuronal viabilities and neurological outcomes were significantly improved 72 h post-SAH in the TAT-Ngb-treated group. Likewise, anti-apoptotic Bcl-2 protein was also elevated obviously. Conversely, pro-apoptotic factors including caspase 3, caspase 9 and Bax were greatly decreased after TAT-Ngb treatment. Our results suggest that Ngb plays a neuroprotective effect in rabbits suffering from SAH possibly through inhibiting the SAH-induced activation of mitochondria apoptotic pathway. Furthermore, TAT-mediated Ngb delivery into brain may be a promising therapeutic approach.

Punica granatum L. Juice Attenuates Experimental Cerebral Vasospasm in the Rabbit Subarachnoid Hemorrhage Model: A Basilar Artery Morphometric Study and Apoptosis.

Background This study investigated the effect of Punica granatum L. (pomegranate) juice on the rabbit basilar artery in an experimental subarachnoid hemorrhage (SAH) model. Methods Eighteen adult male New Zealand white rabbits were randomly divided into three groups: a control group (n = 6), SAH group (n = 6), and SAH + treatment group (n = 6). Basilar artery diameter was measured with magnetic resonance angiography (MRA) in all groups at the beginning of the study. Experimental SAH was created by injecting autologous arterial blood into the cisterna magna. In the treatment group, the subjects were administered a daily dose of 30 ml/kg pomegranate juice via gastric gavage for 4 days after the SAH. The SAH group and SAH + treatment group underwent cerebral MRA after 72 hours. After a neurologic score assessment, all the animals were killed. The wall thickness and lumen area of the basilar artery were measured histometrically in all groups, and the apoptotic cell percentage in the artery was identified. The mean diameter of the basilar artery during MRA was measured. Results Pomegranate improved neurologic functions compared with the SAH group (p < 0.01). The mean basilar artery diameter on MRA in the SAH + treatment group was larger than in the SAH group and smaller than in the control group (p < 0.01 and p < 0.05, respectively). The mean vessel wall thickness value in the SAH + treatment group was lower than in the SAH group (p < 0.01), whereas there was no difference between the control and the SAH + treatment group (p > 0.05). The apoptotic cell rate in the SAH + treatment group was significantly lower than in the SAH group (p < 0.001). Evaluation of the basilar artery luminal area showed no difference between the three groups (p > 0.05). Discussion Pomegranate was shown to have a vasospasm- attenuating effect on the basilar artery in the rabbit SAH model for the first time in our study.

Human tissue kallikrein ameliorates cerebral vasospasm in a rabbit model of subarachnoid hemorrhage

Objectives: Cerebral vasospasm (CVS) and early brain injury are major causes of morbidity and mortality following subarachnoid hemorrhage (SAH). We investigated the efficiency of human tissue kallikrein (HTK) to prevent CVS in a rabbit model of SAH.Methods: Forty-eight Japanese white rabbits were randomly divided into four groups (n = 12 each): control (sham-operated), SAH, SAH + phosphate-buffered saline (PBS, vehicle), and SAH + HTK. Basilar artery (BA) diameters were measured by three-dimensional computed tomography angiography at three time points. Endothelin-1 (ET-1) and nitric oxide (NO) levels in the cerebrospinal fluid (CSF) were assayed 24 h before and 5 and 7 days after SAH. After the last measurement, the animals were killed, and endothelial cell apoptosis was assessed. Bax and Bcl-2 levels in the BA were measured by western blotting.Results: HTK was found to significantly reduce CVS following SAH in rabbits. Inverse changes were observed in ET-1 and NO levels in the CSF collected from the SAH group. HTK increased levels of NO, which has a vasodilatory effect, but did not affect levels of ET-1, which has a vasoconstrictive effect. CTA revealed that HTK treatment significantly increased BA diameter. Moreover, HTK treatment reduced the number of apoptotic cells following SAH, presumably by increasing and decreasing Bcl-2 and Bax expression, respectively.Conclusion: HTK ameliorated CVS and inhibited apoptosis in the BA in a rabbit model of SAH.

Expression of Sphingosine-1-phosphate (S1P) on the cerebral vasospasm after subarachnoid hemorrhage in rabbits.

To demonstrate the relationship between of sphingosine-1-phosphate (S1P) expression and subarachnoid hemorrhage (SAH). The basilar arteries from a "double-hemorrhage" rabbit model of SAH were used to investigate the relation between S1P expression and SAH. Various symptoms, including blood clots, basilar artery cross-sectional area, and S1P phosphatase expression were measured at day 3, 5, 7, 9. The expression of S1P was enhanced in the cerebral vasospasm after subarachnoid hemorrhage in the rabbits. And S1P expression was consistent with the basilar artery cross-sectional area changes at day 3, 5, 7, 9. Sphingosine-1-phosphate expression in the cerebral arterial may be a new indicator in the development of cerebral vasospasm after subarachnoid hemorrhage and provide a new therapeutic method for SAH.

Abstract T P249: Upregulation of Relaxin After Experimental Subarachnoid Hemorrhage

Background and Purpose: Relaxin is a pregnancy hormone which exerts vasodilatory effects by activating nitric oxide synthase and matrix metalloproteinases through receptor (RXFP1). Recently, this vasodilatory effect has been considered useful as a potential therapeutic target in acute heart failure. However, the role of relaxin in the cerebral artery has not been fully explored. In this study, we investigated the role of relaxin in rabbit basilar artery (BA) after subarachnoid hemorrhage (SAH). Methods: Basilar arteries were collected from a rabbit SAH model on days 3, 5, and 7 after SAH. Total RNA was extracted from the BA and a cDNA microarray containing 43,623 genes was performed. The expression of relaxin and RXFP1 mRNA was investigated by quantitative RT-PCR. Serum and cerebrospinal fluid (CSF) relaxin concentrations were measured by ELISA. Perfusion fixation was performed on days 0, 3, 5 and 7, and the localization of RXFP-1 in the BA was examined using immunohistochemistry. Results: The expression of relaxin mRNA was significantly up-regulated on days 5 and 7 compared to the control sample. The expression of RXFP1 mRNA was significantly down-regulated on day 3 and sustained on day 7. The serum relaxin concentration in the rabbit SAH model was not significantly changed after SAH, whereas the CSF relaxin concentration was significantly elevated on days 5 and 7. Immunohistochemistry revealed strong RXFP1 staining in media of the BA on day 0, and showed weak staining on days 3, 5 and 7. Conclusions: Relaxin expression in the BA and relaxin concentration in the CSF increase after SAH, and considerably, relaxin expression is negatively correlated with the RXFP1 expression in the rabbit BA after SAH.

The single and double blood injection rabbit subarachnoid hemorrhage model.

Over the past 30 years, the rabbit subarachnoid hemorrhage model (SAH) has been used for investigating the post-hemorrhage pathology, especially with respect to understanding of the mechanisms of cerebral vasospasm. However, the molecular mechanisms of cerebral vasospasm remain to be elucidated. Furthermore, it is not clear whether the rabbit SAH model is suitable for the investigation of pathological conditions other than cerebral vasospasm, such as early brain injury. Therefore, the properties of the rabbit SAH model need to be validated, and the reasons for using the rabbit should be clarified. This review explores the settings and technical issues of establishing a rabbit cisterna magna single and double blood injection SAH model and discusses the characteristics and feasibilities of the models.

Changes in number of water-filled vesicles of choroid plexus in early and late phase of experimental rabbit subarachnoid hemorrhage model: the role of petrous ganglion of glossopharyngeal nerve.

Cerebrospinal fluid (CSF) secretion may be increased in the early phases of subarachnoid hemorrhage (SAH), possibly via ischemic glossopharyngeal nerve discharges, and decreased due to glossopharyngeal nerve degeneration in the late phase of SAH; but this reflex pathway has not been definitively investigated. We studied the relationship between petrous ganglion of the glossopharyngeal nerve (GPN) and water vesicles of the choroid plexus (CP) in the early and late phases of SAH. This study was conducted on 30 rabbits, divided into four groups, with five rabbits in the control group (group I), five rabbits in the sham group (Group II), and 20 rabbits in the SAH group. In the SAH group, five of the animals were decapitated after 4 days of cisternal blood injections (Group III), and the other 15 animals were decapitated after 20 days of injections (Group IV). The Petrous Ganglia and CPs of lateral ventricles were removed and stained for stereological analysis. The mean number of follicles per cubic millimeter was 5.3 ± 1.2 the in control group (Group I), 4.5 ± 0.9 in the sham group (Group II), 16.60 ± 3.77 the in early decapitated group (Group III), and 4.30 ± 0.84 in the late decapitated group (Group IV). The mean number of degenerated neuron density of petrous ganglions was 6 ± 2, 50 ± 6, 742 ± 96, and 2.420 ± 350 in the control (Group I), sham (Group II), early decapitated (Group III), and late decapitated group (Group IV), respectively. The mean number of water vesicles was statistically different after SAH between the early decapitated group (group III) and the late decapitated group (group IV) (P < 0.05). We studied the relationship between petrous ganglion cells of the GPN and water vesicles of CP in the early and late phases of SAH, and found that CP vesicles are increased in the early phase of SAH due to irritation of GPN, and decreased in the late phase due to ischemic insult of the petrous ganglion and parasympathetic innervation of the CP.

Alterations of Voltage-Dependent Calcium Channel Currents in Basilar Artery Smooth Muscle Cells at Early Stage of Subarachnoid Hemorrhage in a Rabbit Model

ObjectiveTo investigate the changes in the currents of voltage-dependent calcium channels (VDCCs) in smooth muscle cells of basilar artery in a rabbit model of subarachnoid hemorrhage (SAH).MethodsNew Zealand white rabbits were randomly divided into five groups: sham (C), normal (N), 24 hours (S1), 48 hours (S2) and 72 hours (S3) after SAH. Non-heparinized autologous arterial blood (1ml/kg) was injected into the cisterna magna to create SAH after intravenous anesthesia, and 1 ml/kg of saline was injected into cisterna magna in the sham group. Rabbits in group N received no injections. Basilar artery in S1, S2, S3 group were isolated at 24, 48, 72 hours after SAH. Basilar artery in group C was isolated at 72 hours after physiological saline injection. Basilar artery smooth muscle cells were isolated for all groups. Whole-cell patch-clamp technique was utilized to record cell membrane capacitance and VDCCs currents. The VDCCs antagonist nifedipine was added to the bath solution to block the Ca++ channels currents.ResultsThere were no significant differences in the number of cells isolated, the cell size and membrane capacitance among all the five groups. VDCC currents in the S1–S3 groups had higher amplitudes than those in control and sham groups. The significant change of current amplitude was observed at 72 hours after SAH, which was higher than those of 24 and 48 hours. The VDCCs were shown to expression in human artery smooth muscle cells.ConclusionsThe changes of activation characteristics and voltage-current relationship at 72 hours after SAH might be an important event which leads to a series of molecular events in the microenvironment of the basilar artery smooth muscle cells. This may be the key time point for potential therapeutic intervention against subarachnoid hemorrhage.

Gene Expression Profiling and Bioinformatic Analysis of Rabbit Basilar Artery after Experimental Subarachnoid Hemorrhage

Objective: The molecular mechanisms which contribute to the development of vascular events including cerebral vasospasm after subarachnoid hemorrhage (SAH) in cerebral artery remain to be elucidated. In this study, we investigated the time course of changes in the gene expression of cerebral artery using rabbit SAH model and performed bioinformatic analysis of differentially expressed genes. Methods: Rabbit basilar arteries were harvested on days 3, 5, and 7 after initial hemorrhage. Changes in gene expression of the rabbit basilar artery were investigated by using Agilent rabbit oligo microarrays and analyzed the data by Ingenuity Pathway Analysis (IPA). Results: Among investigated 43,623 genes, 1,121 genes were differentially expressed at least 1 time point. We found that the number, magnitude of fold change, and gene expression pattern were most dynamically changed on day 3, whereas narrowing of the basilar artery became most severe on day 5. In microarray datasets analyzed by IPA revealed that 25 biological functions identified from differentially expressed genes were significantly upregulated. Conclusion: Our findings that were based on gene expression analysis followed by bioinformatic analysis may provide a simple basis to interlink the various presumed pathogenesis of vascular events including cerebral vasospasm after SAH.

Study the effects of zonisamide on fine structure of rabbit basilar artery and hippocampus in rabbit subarachnoid hemorrhage model

In this study, we investigated the effect of a novel antiepileptic drug, zonisamide (ZNS), on the basilar artery and hippocampus in a rabbit subarachnoid hemorrhage (SAH) model. Three groups of New Zealand white rabbits were used: a sham (non-SAH) group, an SAH + saline group, and SAH + drug treatment group that received ZNS. In the treatment group, the subjects were given ZNS for 3 days after the SAH. Hippocampal sections were evaluated for neural tissue degeneration. Basilar artery lumen areas and arterial wall thickness were also measured in all groups. The mean luminal area of the SAH + ZNS was significantly greater than the SAH + saline group. In addition, the arterial wall thickness of SAH + ZNS group was significantly thinner than the SAH + saline group. The neuronal degeneration scores of the hippocampal CA1 regions in the SAH + ZNS group were significantly lower than the SAH + saline treatment animals. These results indicate that ZNS has a vasodilatatory effect on the basilar artery and a neuronal protective effect in the CA1 region of the hippocampus in a rabbit SAH model.

Abstract TMP113: Oxidative stress and Extracellular Signal-regulated Kinase (ERK) Play a Key Role in Impairment of Receptor Desensitization and Prolongation of Vascular Reactivity in the Cerebral Artery after Subarachnoid Hemorrhage

Cerebral vasospasm is a critical determinant in the prognosis of subarachnoid hemorrhage (SAH). The vasospasm is characterized by not only enhanced but also prolonged contraction. The enhanced response is attributable to an increased receptor expression, while a prolonged response is attributable to impaired receptor desensitization. This study addressed this hypothesis and investigated the mechanism underlying a prolonged contraction, using a rabbit SAH model and A7r5 smooth muscle cells. A thrombin receptor (PAR 1 )-activating peptide (PAR 1 AP) induced a transient contraction in the basilar arteries of the control rabbits. The subsequent second stimulation produced 8% of the first response. PAR 1 AP induced an enhanced and prolonged contraction in SAH, and the second stimulation produced a 75% response. Thrombin induced an enhanced and prolonged contraction in SAH. This contraction irreversibly persisted even after terminating thrombin stimulation. The enhancement and prolongation of the contractile response after SAH was further observed with angiotensin II, vasopressin and PGF 2 α. The heparinization of autologous blood or the intrathecal application of a thrombin inhibitor, argatroban, prevented the enhancement of contraction, while they had no effect on the prolongation of the contraction. The addition of vitamin C or tempol to argatroban restored the transient response, tachyphylactic attenuation of the second response and reversibility of thrombin contraction. The amount of malondialdehyde, an indicator of oxidative stress, in the brain tissues increased after SAH, and this increase was prevented by either argatroban or vitamin C. The Ca 2+ responses to thrombin and PAR 1 AP in A7r5 cells exhibited a phenomenon similar to those seen with the contractile response in an SAH model. ERK inhibitors restored the transient response, tachyphylactic attenuation and reversibility of thrombin response, while the inhibitors of JNK, p38 kinase or Rho kinase had no effect. In conclusion, oxidative stress and ERK activation play a key role in the impaired receptor desensitization and prolonged vascular reactivity after SAH. Targeting oxidative stress and ERK could provide a novel strategy to normalize vascular reactivity after SAH.

The effect of thiocolchicoside on cerebral vasospasm following experimental subarachnoid hemorrhage in the rabbit

This study investigated the effects of thiocolchicoside to prevent cerebral vasospasm in a rabbit model of subarachnoid hemorrhage. Twenty-four adult male New Zealand white rabbits were randomly divided into three groups of eight rabbits each: group 1 (control), group 2 (subarachnoid hemorrhage), group 3 (treatment). Thiocolchicoside (4mg/kg, intraperitoneally) was administered just before intracisternal blood injection and continued for 72h once a day in the same dose for group 3. Animals were killed 72h after subarachnoid hemorrhage. Basilar artery cross-sectional areas and arterial wall thicknesses were measured in all groups. Intraperitoneal administration of thiocolchicoside was found to attenuate cerebral vasospasm after subarachnoid hemorrhage in rabbits. Thiocolchicoside treatment was determined to be effective in increasing the luminal area and reducing the wall thickness of the basilar artery. Our findings, for the first time, showed that TCC can prevent vasospasm induced by SAH. Our results also showed that GABAergic activity may play an important role in cerebral vasospasm etiopathogenesis. In conclusion, the thiocolchicoside treatment might be beneficial in preventing vasospasm after subarachnoid hemorrhage, thus showing potential for clinical application.