OBJECTIVETo assess the relationship between protease-activated receptor 1 (PAR1) expression in the basilar artery and cerebral vasospasm (CVS) in a rat model of subarachnoid hemorrhage (SAH).

METHODSTwenty-four SD rats were randomized into normal control group, SAH 3-days group, SAH 5-days group and SAH 7-days group. Rat models of SAH were established by two injections of blood into the cisterna magna and the behavioral changes of the rats were observed. The basilar arteries were taken at 3, 5, or 7 days following the modeling for measuring the cross-sectional area of the basilar artery and for immunohistochemical detection of PAR1 expression.

RESULTSThe SAH model rats, especially those in SAH 3-days group, presented with obvious neurological deficits, which was not found in the normal control group. CVS was not observed in the normal control group but occurred in the SAH model rats, which showed reduced cross-sectional area of the basilar artery and worsening spasm over time. The expression level of PAR1 tended to increase gradually in SAH 3-days, SAH 5-days and SAH 7-days groups. Pearson correlation analysis showed an inverse correlation between the expression of PAR1 and the cross-sectional area of the basilar artery (r=-0.779, P<0.01).

CONCLUSIONSThe expression of PAR1 increases significantly in rat basilar artery wall following SAH in positive correlation with the severity of CVS, suggesting the role of thrombin in the pathological process of CVS after SAH.

Animals ; Basilar Artery ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptor, PAR-1 ; metabolism ; Subarachnoid Hemorrhage ; metabolism ; Vasospasm, Intracranial ; metabolism

We have checked levels of leukotriene(LT) C4, one of the arachidonic acid(AA) metabolites, in the lumbar, cisternal and ventricular cerebrospinal fluid(CSF) of 37 patients admitted with diagnosis of aneurysmal subarachnoid hemorrhage(SAH) and in lumbar CSF of 10 patients without aneurysmal SAH as the control group. We compared the levels of LTC4 in the CSF of the patients with aneurysmal SAH with those of the control group. We observed the changes of levels of LTC4 periodically after the onset of SAH. We devided the data of patients with aneurysmal SAH into 3 groups according to sampling days(respectively 1-4, 5-11, 12-24 days after SAH) and the clinical spasm group was compared with that of the non-spasm group. We also looked for the differences in the sampling sites and the correlation between the white blood cell counts and the levels of LTC4 in the CSF. The results of this study showed that the mean level of CSF LTC4(+/- standard deviation) of the SAH group was significantly higher than that of the control group(215.59+/-94.95 vs. 98.44+/-31.72pg/ml, respectively : P<0.001). The level of the CSF LTC4 progressively increased upto 7-8 days after SAH and decreased thereafter in the spasm group. The level of the CSF LTC4 of the spasm group was significantly higher than that of the non-spasm group(239.03+/-49.94 vs. 163.06+/-64.39pg/ml, respectively : P<0.05) in the first 4 days after SAH. There was no significant difference in the level of CSF LTC4 in the ventricular, cisternal, and lumbar CSF statistically(196.25+/-61.15 vs. 222.51+/-101.50 vs. 233.40+/-100.85pg/ml, respectively : P>0.05) even though we expected the level in the cisternal CSF to be higher than the lumbar CSF. There was no correlation between the white blood cell counts and the levels of LTC4 in the CSF(correlation coefficient=0.1240). From this study it is concluded that : 1) the AA metabolism via the lipoxygenase pathway is enhanced after SAH ; 2) the LTC4 may play a role in the pathogenesis of cerebral vasospasm, especially in the early days after SAH ; 3) the extraction of CSF via the external ventricular or cisternal drainage may decrease substances such as LTC4 which was thought to be vasoconstrictor material ; and 4) the granulocyte production of the LTC4 accounts for only a small part.
Aneurysm* ; Arachidonic Acid ; Cerebrospinal Fluid* ; Diagnosis ; Drainage ; Granulocytes ; Humans ; Leukocyte Count ; Leukotriene C4* ; Lipoxygenase ; Metabolism ; Spasm ; Subarachnoid Hemorrhage* ; Vasospasm, Intracranial

OBJECTIVETo assess the value of (1)H-magnetic resonance spectroscopy ((1)H-MRS) in evaluating cerebral vasospasm resulting from subarachnoid hemorrhage (SAH).

METHODSSix dogs were subjected to autologous non-heparinized blood injection via cisternal puncture twice at one-day interval to establish models of SAH, and another 6 received injections with normal saline in an identical manner. (1)H-MRS scan was performed on the 3rd, 7th and 14th days after the injections to measure the changes of N-acetylaspartate (NAA), creatine (Cr) and choline (Cho). After the (1)H-MRS scan, all the dogs underwent brain digital subtraction angiography (DSA) for determining the basilar artery diameter.

RESULTSDSA results on day 3 presented development of obvious vasospasm of the basilar artery, which was most evident on day 7 and recovered obviously on day 14. (1)H-MRS results demonstrated obvious changes of NAA, Cho and Cr on days 3 and 7 in SAH model group, and NAA declined to the lowest level on day 3 followed by gradual ascending till reaching the normal level on day 14. Cho decreased slightly on day 3, then increased and reached the peak level on day 7 and then decreased. Cr rose steadily from day 3 to 14, but since day 7, the rise slowed down obviously and Cr maintain a level not significantly different from that on day 14 (P>0.05). The functional results of (1)H-MRS were consistent with the DSA results.

CONCLUSION(1)H-MRS can be used to monitor the development of cerebral vasospasm resulting from SAH as a good evaluation method for functional imaging.

Animals ; Aspartic Acid ; analogs & derivatives ; metabolism ; Choline ; metabolism ; Creatine ; metabolism ; Dogs ; Female ; Magnetic Resonance Spectroscopy ; methods ; Male ; Protons ; Subarachnoid Hemorrhage ; complications ; Time Factors ; Vasospasm, Intracranial ; diagnosis ; etiology ; metabolism

In order to find out the relationship between arachidonic acid(AA) metabolites and the development of vasospasm following a subarachnoid hemorrhage(SAH), we evaluated the cerebrospinal fluid(CSF) levels of the two main AA metabolites, prostacyclin(PGI2) and thromboxane A2(TXAZ) by measuring their stable degredation products 6-keto-prostaglandin F1alpha(PGF1) and thromboxane B2(TXB2) using radioimmunoassay methods in 32 patients after an aneurysmal rupture and in 11 patients without an aneurysmal rupture as a control group. We compared the data between aneurysmal ruptured patients and control group patients. We also divided the data of the aneurysmal ruptured patients into 3 groups checking them between 1-4, 5-11, and 12-28 days after the SAH, and compared the data among the groups, then the data was also compared between non-vasospasm and clinical or severe angiographic vasospasm groups of patients. The results showed that the AA metabolism was enhanced after the SAH, The TXB2 increased the greatest amount in 1-4 days after the SAH and significantly decreased statistically 12 days after the SAH(p<0.002). This study also showed that the TXB2 level was significantly higher statistically in 1 to 4 days in the clinical or angiogrophically severe vasospasm group than in the non-vasospasm group of patients(p<0.032). PGF1 did not show any statistically significant changes according to the number of SAH days or a difference between the vasospasm and non-vasospasm groups. This result suggests if the AA metabolites are involved in the pathogenesis of cerebral vasospasm, and the lumbar CSF levels of AA metabolites in aneurysmal patients reflect the arterial synthesis of PGI2 and platelet origin of TXA2, the elevation of TXA2 or other vasoconstrictor prostaglandins is more likely to play a major role in the pathogenesis of vasospasm than PGI2 deficiency. The measurements of the CSF TXB2 in 1 to 4 days after a SAH may have an expectant value in the development of clinical or severe angiographic vasospasm(exclude the accompanying intraventricular hemorrhage patients).
Aneurysm* ; Arachidonic Acid ; Blood Platelets ; Cerebrospinal Fluid* ; Epoprostenol ; Hemorrhage ; Humans ; Metabolism ; Prostaglandins I ; Radioimmunoassay ; Rupture ; Subarachnoid Hemorrhage* ; Thromboxane A2 ; Thromboxane B2* ; Vasospasm, Intracranial

OBJECTIVES: Subarachnoid hemorrhage (SAH) is a serious cerebrovascular disease. Early brain injury (EBI) and cerebral vasospasm are the main reasons for poor prognosis of SAH patients. The specific inhibitor of histone deacetylase 6 (HDAC6), tubastatin A (TubA), has been proved to have a definite neuroprotective effect on a variety of animal models of acute and chronic central nervous system diseases. However, the neuroprotective effect of TubA on SAH remains unclear. This study aims to investigate the expression and localization of HDAC6 in the early stage of SAH, and to evaluate the protective effects of TubA on EBI and cerebral vasospasm after SAH and the underlying mechanisms. METHODS: Adult male SD rats were treated with modified internal carotid artery puncture to establish SAH model. In the first part of the experiment, rats were randomly divided into 6 groups: a sham group, a SAH-3 h group, a SAH-6 h group, a SAH-12 h group, a SAH-24 h group, and a SAH-48 h group. At 3, 6, 12, and 24 h after SAH modeling, the injured cerebral cortex of rats in each group was taken for Western blotting to detect the expression of HDAC6. In addition, the distribution of HDAC6 in the cerebral cortex of the injured side was measured by immunofluorescence double staining in SAH-24 h group rats. In the second part, rats were randomly divided into 4 groups: a sham group, a SAH group, a SAH+TubA_L group (giving 25 mg/kg TubA), and a SAH+TubA_H group (giving 40 mg/kg TubA). At 24 h after modeling, the injured cerebral cortex tissue was taken for Western blotting to detect the expression levels of HDAC6, endothelial nitric oxide synthase (eNOS), and inducible nitric oxide synthase (iNOS), terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining to detect apoptosis, and hematoxylin and eosin (HE) staining to detect the diameter of middle cerebral artery. RESULTS: The protein expression of HDAC6 began to increase at 6 h after SAH (P<0.05), peaked at 24 h (P<0.001), and decreased at 48 h, but there was still a difference compared with the sham group (P<0.05). HDAC6 is mainly expressed in the cytoplasm of the neurons. Compared with the sham group, the neurological score was decreased significantly and brain water content was increased significantly in the SAH group (both P<0.01). Compared with the SAH group, the neurological score was increased significantly and brain water content was decreased significantly in the SAH+TubA_H group (both P<0.05), while the improvement of the above indexes was not significant in the SAH+TubA_L group (both P>0.05). Compared with the sham group, the expression of eNOS was significantly decreased (P<0.01) and the expressions of iNOS and HDAC6 were significantly increased (P<0.05 and P<0.01, respectively) in the SAH group. Compared with the SAH group, the expression of eNOS was significantly increased, and iNOS and HDAC6 were significantly decreased in the SAH+TubA group (all P<0.05). Compared with the SAH group, the number of TUNEL positive cells was significantly decreased and the diameter of middle cerebral artery was significantly increased in the SAH+TubA group (both P<0.05) . CONCLUSIONS HDAC6 is mainly expressed in neurons and is up-regulated in the cerebral cortex at the early stage of SAH. TubA has protective effects on EBI and cerebral vasospasm in SAH rats by reducing brain edema and cell apoptosis in the early stage of SAH. In addition, its effect of reducing cerebral vasospasm may be related to regulating the expression of eNOS and iNOS.
Rats ; Male ; Animals ; Rats, Sprague-Dawley ; Subarachnoid Hemorrhage/drug therapy* ; Vasospasm, Intracranial/metabolism* ; Histone Deacetylase Inhibitors/therapeutic use* ; Neuroprotective Agents/therapeutic use* ; Histone Deacetylase 6/pharmacology* ; Apoptosis ; Brain Injuries/drug therapy*

Fluoxetine, an anti-depressant drug, has recently been shown to provide neuroprotection in central nervous system injury, but its roles in subarachnoid hemorrhage (SAH) remain unclear. In this study, we aimed to evaluate whether fluoxetine attenuates early brain injury (EBI) after SAH. We demonstrated that intraperitoneal injection of fluoxetine (10 mg/kg per day) significantly attenuated brain edema and blood-brain barrier (BBB) disruption, microglial activation, and neuronal apoptosis in EBI after experimental SAH, as evidenced by the reduction of brain water content and Evans blue dye extravasation, prevention of disruption of the tight junction proteins zonula occludens-1, claudin-5, and occludin, a decrease of cells staining positive for Iba-1, ED-1, and TUNEL and a decline in IL-1β, IL-6, TNF-α, MDA, 3-nitrotyrosine, and 8-OHDG levels. Moreover, fluoxetine significantly improved the neurological deficits of EBI and long-term sensorimotor behavioral deficits following SAH in a rat model. These results indicated that fluoxetine has a neuroprotective effect after experimental SAH.
Animals ; Apoptosis ; drug effects ; Blood-Brain Barrier ; drug effects ; Brain Edema ; drug therapy ; etiology ; Cytokines ; genetics ; metabolism ; Disease Models, Animal ; Fluoxetine ; pharmacology ; therapeutic use ; In Situ Nick-End Labeling ; Male ; Neuroprotective Agents ; pharmacology ; therapeutic use ; Pain Measurement ; Psychomotor Performance ; drug effects ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley ; Subarachnoid Hemorrhage ; complications ; drug therapy ; pathology ; Time Factors ; Vasospasm, Intracranial ; drug therapy ; etiology