scholarly journals Brain injury after intracerebral hemorrhage in spontaneously hypertensive rats

2011 ◽  
Vol 114 (6) ◽  
pp. 1805-1811 ◽  
Author(s):  
Gang Wu ◽  
Xuhui Bao ◽  
Guohua Xi ◽  
Richard F. Keep ◽  
B. Gregory Thompson ◽  
...  
Keyword(s):  
Brain Injury ◽  
Intracerebral Hemorrhage ◽  
Brain Edema ◽  
Neuronal Death ◽  
Spontaneously Hypertensive Rats ◽  
Neurological Deficits ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Autologous Whole Blood

Object Hypertension is the main cause of spontaneous intracerebral hemorrhages (ICHs), but the effects of hypertension on ICH-induced brain injury have not been well studied. In this study, the authors examined ICH-induced brain injury in spontaneously hypertensive rats (SHRs). Methods This 2-part study was performed in 12-week-old male SHRs and Wistar Kyoto (WKY) rats. First, the rats received an intracaudate injection of 0.3 U collagenase, and hematoma sizes were determined at 24 hours. Second, rats were injected with 100 μl autologous whole blood into the right basal ganglia. Brain edema, neuronal death, ferritin expression, microglia activation, and neurological deficits were examined. Results Hematoma sizes were the same in SHR and WKY rats 24 hours after collagenase injection. The SHRs had greater neuronal death and neurological deficits after blood injection. Intracerebral hemorrhage also resulted in higher brain ferritin levels and stronger activation of microglia in SHRs. However, perihematomal brain edema was the same in the SHRs and WKY rats. Conclusions Moderate chronic hypertension resulted in more severe ICH-induced neuronal death and neurological deficits, but did not exaggerate hematoma enlargement and perihematomal brain edema in the rat ICH models.

Estrogen therapy for experimental intracerebral hemorrhage in rats

2005 ◽  
Vol 103 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Takehiro Nakamura ◽  
Ya Hua ◽  
Richard F. Keep ◽  
Jung-Weon Park ◽  
Guohua Xi ◽  
...  
Keyword(s):  
Brain Injury ◽  
Intracerebral Hemorrhage ◽  
Brain Edema ◽  
Estrogen Therapy ◽  
Female Rats ◽  
Male Rats ◽  
Neurological Deficits ◽  
Sprague Dawley ◽  
Autologous Whole Blood ◽  
17Β Estradiol

Object The aims of this study were to determine the following: whether there are sex differences in intracerebral hemorrhage (ICH) induced brain injury in rats, whether delayed administration of 17β-estradiol can reduce ICH-induced brain damage, and whether these effects are estrogen receptor (ER)-dependent. Methods Male and female Sprague—Dawley rats received an infusion of 100 µl autologous whole blood into the right basal ganglia. Twenty-four hours later the rats were killed. The effects of 17β-estradiol on ICH-induced brain injury were examined by measuring brain edema and neurological deficits. Both ER-α and hemeoxygenase (HO)-1 were investigated through Western blot and immunohistochemical analysis. Brain edema was significantly less severe in female compared with that in male rats. The ER antagonist ICI 182,780 exacerbated ICH-induced brain edema in female but not in male rats, indicating that ER-α activation during ICH is protective in female rats. Administration of exogenous 17β-estradiol in male, but not in female, rats significantly attenuated brain edema, neurological deficits, and ICH-induced changes in HO-1 when given 2 hours after hemorrhage. The effects of exogenous 17β-estradiol occurred through an ER-independent mechanism. Conclusions Results in this study indicate that 17β-estradiol could be a potential therapeutic agent for ICH.

Deferoxamine-induced attenuation of brain edema and neurological deficits in a rat model of intracerebral hemorrhage

2003 ◽  
Vol 15 (4) ◽  
pp. 1-7 ◽  
Author(s):  
Takehiro Nakamura ◽  
Richard F. Keep ◽  
Ya Hua ◽  
Timothy Schallert ◽  
Julian T. Hoff ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Brain Injury ◽  
Intracerebral Hemorrhage ◽  
Brain Edema ◽  
Iron Chelator ◽  
Iron Accumulation ◽  
Neurological Deficits ◽  
Sprague Dawley ◽  
Autologous Whole Blood ◽  
The Right

Object In the authors' previous studies they found that brain iron accumulation and oxidative stress contribute to secondary brain damage after intracerebral hemorrhage (ICH). In the present study they investigated whether deferoxamine, an iron chelator, can reduce ICH-induced brain injury. Methods Male Sprague–Dawley rats received an infusion of 100 μl of autologous whole blood into the right basal ganglia and were killed 1, 3, or 7 days thereafter. Iron distribution was examined histochemically (enhanced Perl reaction). The effects of deferoxamine on ICH-induced brain injury were examined by measuring brain edema and neurological deficits. Apurinic/apyrimidinic endonuclease/redox effector factor–1 (APE/Ref-1), a repair mechanism for DNA oxidative damage, was quantitated by Western blot analysis. Iron accumulation was observed in the perihematoma zone beginning 1 day after ICH. Deferoxamine attenuated brain edema, neurological deficits, and ICH-induced changes in APE/Ref-1. Conclusions Deferoxamine and other iron chelators may be potential therapeutic agents for treating ICH. They may act by reducing the oxidative stress caused by the release of iron from the hematoma.

Deferoxamine-induced attenuation of brain edema and neurological deficits in a rat model of intracerebral hemorrhage

2004 ◽  
Vol 100 (4) ◽  
pp. 672-678 ◽  
Author(s):  
Takehiro Nakamura ◽  
Richard F. Keep ◽  
Ya Hua ◽  
Timothy Schallert ◽  
Julian T. Hoff ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Brain Injury ◽  
Intracerebral Hemorrhage ◽  
Brain Edema ◽  
Oxidative Dna Damage ◽  
Iron Accumulation ◽  
Neurological Deficits ◽  
Content Type ◽  
Autologous Whole Blood ◽  
Fine Print

Object. Previous studies undertaken by the authors have indicated that iron accumulation and oxidative stress in the brain contribute to secondary brain damage after intracerebral hemorrhage (ICH). In the present study the authors investigate whether deferoxamine, an iron chelator, can reduce ICH-induced brain injury. Methods. Male Sprague—Dawley rats each received an infusion of 100 µl of autologous whole blood into the right basal ganglia and were killed 1, 3, or 7 days later. Iron distribution was examined histochemically (enhanced Perls reaction). The effects of deferoxamine on ICH-induced brain injury were examined by measuring brain edema and neurological deficits. Immunohistochemical analysis was performed to investigate 8-hydroxyl-2′-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage, and Western blot analysis was performed to measure the amount of apurinic/apyrimidinic endonuclease/redox effector factor—1 (APE/Ref-1), a repair mechanism for DNA oxidative damage. Iron accumulation was observed in the perihematomal zone from 1 day after ICH. Deferoxamine attenuated brain edema, neurological deficits, and ICH-induced changes in 8-OHdG and APE/Ref-1. Conclusions. Deferoxamine and other iron chelators may be potential therapeutic agents for ICH. They may act by reducing the oxidative stress caused by the release of iron from the hematoma.

scholarly journals Reduction of Tissue Plasminogen Activator-Induced Hemorrhage and Brain Injury by Free Radical Spin Trapping after Embolic Focal Cerebral Ischemia in Rats

2000 ◽  
Vol 20 (3) ◽  
pp. 452-457 ◽  
Author(s):  
Minoru Asahi ◽  
Kazuko Asahi ◽  
Xiaoying Wang ◽  
Eng H. Lo
Keyword(s):  
Free Radical ◽  
Brain Injury ◽  
Cerebral Ischemia ◽  
Reperfusion Injury ◽  
Cerebral Hemorrhage ◽  
Spontaneously Hypertensive Rats ◽  
Neurological Deficits ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Tissue Plasminogen

Thrombolytic stroke therapy with tissue plasminogen activator (tPA) remains complicated by serious risks of cerebral hemorrhage and brain injury. In this study, a novel model of tPA-induced hemorrhage was used in spontaneously hypertensive rats to examine the correlates of hemorrhage, and test methods of reducing hemorrhage and brain injury. Homologous blood clot emboli were used to occlude the middle cerebral artery in spontaneously hypertensive rats, and delayed administration of tPA (6 hours postischemia) resulted in high rates of cerebral hemorrhage 24 hours later. Compared with untreated rats, tPA significantly increased hemorrhage volumes by almost 85%. Concomitantly, infarction and neurological deficits were worsened by tPA. A parallel experiment in normotensive Wistar-Kyoto rats showed markedly reduced rates of hemorrhage, and tPA did not significantly increase hemorrhage volumes. To examine whether tPA-induced hemorrhage was caused by the delayed onset of reperfusion per se, another group of spontaneously hypertensive rats was subjected to focal ischemia using a mechanical method of arterial occlusion. Delayed (6 hours) reperfusion via mechanical means did not induce hemorrhage. However, administration of tPA plus delayed mechanical reperfusion significantly increased hemorrhage volumes. Since reperfusion injury was implicated, a final experiment compared outcomes in spontaneously hypertensive rats treated with tPA plus the free radical spin trap α-phenyl tert butyl nitrone (α-PBN) versus tPA alone. tPA-induced hemorrhage volumes were reduced by 40% with α-PBN, and infarction and neurological deficits were also decreased. These results indicate that (1) blood pressure isanimportant correlate of tPA-induced hemorrhage, (2) tPA interacts negatively with reperfusion injury to promote hemorrhage, and (3) combination therapies with anti-free radical treatments may reduce the severity of tPA-induced hemorrhage and brain injury after cerebral ischemia.

scholarly journals Cilostazol, Not Aspirin, Reduces Ischemic Brain Injury via Endothelial Protection in Spontaneously Hypertensive Rats

Stroke ◽  
2011 ◽  
Vol 42 (9) ◽  
pp. 2571-2577 ◽  
Author(s):  
Naoki Oyama ◽  
Yoshiki Yagita ◽  
Miki Kawamura ◽  
Yukio Sugiyama ◽  
Yasukazu Terasaki ◽  
...  
Keyword(s):  
Brain Injury ◽  
Spontaneously Hypertensive Rats ◽  
Ischemic Brain Injury ◽  
Hypertensive Rats ◽  
Ischemic Brain ◽  
Spontaneously Hypertensive

Abstract 11003: Hypothalamic Activated Microglia With Morphological Changes Accelerate Blood Pressure Elevation During the Hypertension Development Phase in Stroke-prone Spontaneously Hypertensive Rats

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Ko Takesue ◽  
Takuya Kishi ◽  
Yoshitaka Hirooka
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Development Phase ◽  
Hypertensive Rats ◽  
Blood Pressure Elevation ◽  
Spontaneously Hypertensive ◽  
Activated Microglia ◽  
Wky Rats ◽  
Pressure Elevation ◽  
Hypertension Development

Introduction: A recent paradigm shift in cardiovascular pathophysiology is the impact of inflammation on hypertension. Inflammation within the paraventricular nucleus of the hypothalamus (PVN) is an important pathology of sympathetic hyperactivity, and is mainly mediated by innate immune cells, microglia. Activated microglia with alteration of their morphology produce inflammatory cytokines. Previous reports demonstrated that microglia within the PVN have activated morphology in angiotensin II-induced hypertensive rats and spontaneously hypertensive rats compared with normotensive control Sprague-Dawley rats or Wistar-Kyoto (WKY) rats. However, the role of activated microglia in the PVN in blood pressure elevation associated with sympathetic hyperactivity remains unknown. In the present study, we determined whether inhibition of microglial activation within the PVN attenuates the blood pressure elevation in genetically hypertensive rats. Methods and Results: We evaluated the activation of PVN microglia, identified by microglia specific ionized calcium-binding adaptor molecule 1 immunoreactivity, by measuring the roundness and the perimeter of microglia at 6 weeks of age, early hypertension development phase in stroke-prone spontaneously hypertensive rats (SHRSP) and compared with them in age-matched normotensive WKY rats. At 6 weeks of age, increased roundness and shortening of perimeter of microglia, indicating activated microglia, were observed in SHRSP compared with those in WKY rats. Then, we performed intracerebroventricular (ICV) administration of minocycline (5 μg/h) to deactivate microglia at 6 weeks of age for 4 weeks. ICV administration of minocycline significantly attenuated systolic blood pressure elevation in SHRSP over 4 weeks (at the end of experiments; 203.2±2.2 mm Hg vs. 215.9±2.7 mm Hg, n=8-9, P<0.05), but not in WKY rats. At 10 weeks of age, morphological analysis revealed that ICV minocycline significantly decreased the roundness and increased the perimeter of microglia, indicating deactivation of microglia, within the PVN in SHRSP. Conclusions: Hypothalamic activated microglia with morphologic changes accelerate blood pressure elevation during the hypertension development phase in SHRSP.

Vasopressin V2 receptor enhances gain of baroreflex in conscious spontaneously hypertensive rats

1999 ◽  
Vol 276 (3) ◽  
pp. R872-R879 ◽  
Author(s):  
Donella B. Sampey ◽  
Louise M. Burrell ◽  
Robert E. Widdop
Keyword(s):  
Receptor Antagonist ◽  
Spontaneously Hypertensive Rats ◽  
Pressor Response ◽  
Receptor Subtype ◽  
Hypertensive Rats ◽  
Receptor Antagonists ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Baroreflex Function ◽  
Shr And Wky Rats

The aim of the present study was to determine the receptor subtype involved in arginine vasopressin (AVP)-induced modulation of baroreflex function in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats using novel nonpeptide AVP V1- and V2-receptor antagonists. Baroreceptor heart rate (HR) reflex was investigated in both SHR and WKY rats which were intravenously administered the selective V1- and V2-receptor antagonists OPC-21268 and OPC-31260, respectively. Baroreflex function was assessed by obtaining alternate pressor and depressor responses to phenylephrine and sodium nitroprusside, respectively, to construct baroreflex curves. In both SHR and WKY rats baroreflex activity was tested before and after intravenous administration of vehicle (20% DMSO), OPC-21268 (10 mg/kg), and OPC-31260 (1 and 10 mg/kg). Vehicle did not significantly alter basal mean arterial pressure (MAP) and HR values or baroreflex function in SHR or WKY rats. The V1-receptor antagonist had no significant effect on resting MAP or HR values or on baroreflex parameters in both groups of rats, although this dose was shown to significantly inhibit the pressor response to AVP (5 ng iv; ANOVA, P < 0.05). In SHR but not WKY rats the V2-receptor antagonist significantly attenuated the gain (or slope) of the baroreflex curve (to 73 ± 3 and 79 ± 7% of control for 1 and 10 mg/kg, respectively), although AVP-induced pressor responses were also attenuated with the higher dose of the V2-receptor antagonist. These findings suggest that AVP tonically enhances baroreflex function through a V2 receptor in the SHR.

Tolerance to hypoxia of myocardium from adult and aged spontaneously hypertensive rats

1987 ◽  
Vol 252 (6) ◽  
pp. H1096-H1104 ◽  
Author(s):  
W. W. Brooks ◽  
J. S. Ingwall ◽  
C. H. Conrad ◽  
C. Holubarsch ◽  
O. H. Bing
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Energy Charge ◽  
High Energy ◽  
Left Ventricular ◽  
Adenylate Energy Charge ◽  
Papillary Muscles ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wky Rats ◽  
Tolerance To Hypoxia

Myocardial mechanics and high-energy phosphate content [ATP and creatine phosphate (CrP)] of isolated left ventricular papillary muscle preparations from male spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) were compared at 6 and 18 mo of age. In comparison with oxygenated (95% O2-5% CO2) glucose-supplied (5.5 mM) papillary muscles from hearts of WKY rats, papillary muscles from hypertrophied hearts of the 18-mo-old SHR exhibited a prolonged time to peak tension, electromechanical delay time, and an increase in resting tension measured at the apex of the length-tension curve. Adenine nucleotide (ATP and ADP) contents of oxygenated papillary muscles were not significantly different between SHR and WKY strains at 6 or 18 mo of age, but CrP content of hearts from adult WKY and SHR were higher than for aged WKY and SHR rats. For up to 30 min of hypoxia (95% N2-5% CO2), muscles from the 18-mo-old SHR and WKY rats demonstrated improved tolerance to hypoxia compared with muscles from younger animals. However, at 60 min of hypoxia the 18-mo-old SHR demonstrated lower active tension and adenylate energy charge [(1/2 ADP + ATP)/(ATP + ADP + AMP)]. At higher glucose concentrations (22 mM), both 18-mo-old WKY and SHR demonstrated improved tolerance to hypoxia; moreover, the differences between strains were no longer evident. Following reoxygenation with 5.5 mM glucose, contracture tension and CrP content recovered to near prehypoxic control levels, whereas developed tension and ATP content remained moderately depressed for all groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Sign in / Sign up

Export Citation Format

Share Document