Rat Common Carotid Artery Research Articles

Lipid Peroxidation in Chronic Cerebral HypoperfusionInduced Neurodegeneration in Rats

Introduction: Reduced cerebral blood fl ow is associated with neurodegenerative disorders and dementia, in particular. Experimental evidence has demonstrated the initiating role of chronic cerebral hypoperfusion in neuronal damage to the hippocampus, the cerebral cortex, the white matter areas and the visual system. Permanent, bilateral occlusion of the common carotid arteries of rats (two vessel occlusion - 2VO) has been introduced for the reproduction of chronic cerebral hypoperfusion as it occurs in Alzheimer’s disease and human aging. Increased generation of free radicals through lipid peroxidation can damage neuronal cell membrane. Markers of lipid peroxidation have been found to be elevated in brain tissues and body fl uids in neurodegenerative diseases, including Alzheimer’s disease, Parkinson disease and amyotrophic lateral sclerosis. Materials and Methods: Malondialdehyde (MDA), final product of lipid peroxidation, was estimated by thiobarbituric acid-reactive substances (TBARS) assay kit at eight weeks after induction of 2VO in the rats and control group. Results: Our study revealed a highly signifi cant (p<0.001) increase in the mean MDA concentration (12.296 ± 1.113 μM) in 2VO rats as compared to the control group (5.286 ± 0.363 μM) rats. Conclusion: Therapeutic strategies to modulate lipid peroxidation early throughout the course of the disease may be promising in slowing or possibly preventing neurodegenerative disorders.

Role of stromal-derived factor-1"</alpha>//CXCR4 in neo-intimal repair

Neo-intimal hyperplasia is one of the major causes of restenosis in which stromal cell-derived factor-1<alpha> (SDF-1α) and its receptor CXCR4 play an important role. In a rat common carotid artery balloon injury model, the number of CD34(+)CXCR4(+) cells was significantly increased immediately after injury (p < 0.01), followed by a gradual decrease to baseline seven days after the injury. Furthermore, the plasma (SDF-1α) level was markedly elevated, and peaked 24 hours after injury (p < 0.01), followed by a rapid decrease to baseline level seven days after the injury. In the injured common carotid artery, the mRNA expression of (SDF-1α) was elevated immediately after injury, followed by a gradual decline, but that of CXCR4 was increased four days after injury. Immuno-histochemistry displayed CXCR4-positive staining one day after injury, which then gradually increased and continued for at least one month. In addition, administration of AMD3100 (200 ng/kg, i.p.), a CXCR4 antagonist, did not affect the number of CD34(+)CXCR4(+) cells, the elevated level of plasma (SDF-1α) and expression of (SDF-1α) mRNA. The expression of CXCR4 mRNA and protein however was markedly decreased, and detectable CXCR4-positive cells occurred four days after injury, followed by a decreased intensity of staining. We also found that, three months after balloon injury, stenosis of the carotid artery intima in the group that received AMD3100 was significantly less than in the untreated group (p < 0.05). Therefore, (SDF-1α)/CXCR4 played a crucial role in the intimal hyperplasia, and restenosis may have be attenuated after inhibition of CD34(+)CXCR4(+) cells in the intima.

Effect of rat common carotid artery occlusion on vascular action of adenosine

Background Adenosine is a purine nucleoside that contributes to regulation of vascular tone in different blood vessels, especially in pathological conditions with ischemia and subsequent hypoxia. Prior studies also suggested that relaxations induced by adenosine could be dependent upon the presence of vascular endothelium and activation of various potassium channels. In regard to the previous facts the aim of this study was to investigate effect of adenosine on isolated rat common carotid artery submitted to occlusion.

E0050 Effect of Bosentan on carotid artery restenosis in rat and correlation of serum VEGF

ObjectiveTo investigate the effect of Bosentan on carotid artery restenosis in rat and correlation of serum vascular endothelia growth factor (VEGF).Methods36 Wistar rats were divided randomly into three groups: control...

E0210 Cilostazol reduces neointimal hyperplasia by Inhibition superoxode production and expression of lectin-like oxidised LDL receptor-1 after balloon common arterial injury in a rat model

Lectin-like oxidised low-density lipoprotein receptor-1 (LOX-1) is a membrane protein that can support the binding, internalisation, and proteolytic degradation of oxidised low-density lipoprotein. The LOX-1 expression and superoxide generation increases...

Contribution of Thromboxane A2 in Rat Common Carotid Artery Response to Serotonin

Serotonin is a vasoactive substance that in different blood vessels mostly induces vasoconstriction. Considering the important role of common carotid artery in brain blood supply, the aims of this study were to investigate the effect of serotonin on isolated rat common carotid artery and also to examine participation of intact endothelium, cyclooxygenase products, Ca++ channels and 5-HT2 receptors in serotonin-evoked action. Endothelium was mechanically removed from some vascular rings. Circular artery segments were placed in organ baths containing Krebs–Ringer bicarbonate solution. Cumulative concentration-contraction curves for serotonin were obtained in rings previously equilibrated at basal tone. Serotonin produced concentration-dependent contraction, which was unaltered by endothelial denudation. Serotonin-induced effect was notably and comparably reduced by indomethacin (cyclooxygenase inhibitor) or OKY–046 (thromboxane A2-synthase inhibitor) on intact or denuded rings. Nifedipine (Ca++ channel blocker) or ketanserin (5-HT2 receptor antagonist) strongly reduced serotonin-evoked effect. Our results suggest that serotonin produced concentration-dependent and endothelium-independent contraction of carotid artery, which was initiated by activation of 5-HT2 receptors located on smooth muscle cells and mediated via L-type Ca++ channels. Thromboxane A2 from smooth muscle cells notably contributed to the overall contraction of carotid artery induced by serotonin.

Magnetic Tagging Increases Delivery of Circulating Progenitors in Vascular Injury

We sought to magnetically tag endothelial progenitor cells (EPCs) with a clinical agent and target them to a site of arterial injury using a magnetic device positioned outside the body. Circulating EPCs are involved in physiological processes such as vascular re-endothelialization and post-ischemic neovascularization. However, the success of cell therapies depends on the ability to deliver the cells to the site of injury. Human EPCs were labeled with iron oxide superparamagnetic nanoparticles. Cell viability and differentiation were tested using flow cytometry. Following finite element modeling computer simulations and flow testing in vitro, angioplasty was performed on rat common carotid arteries to denude the endothelium and EPCs were administered with and without the presence of an external magnetic device for 12 min. Computer simulations indicated successful external magnetic cell targeting from a vessel with flow rate similar to a rat common carotid artery; correspondingly there was a 6-fold increase in cell capture in an in vitro flow system. Targeting enhanced cell retention at the site of injury by 5-fold at 24 h after implantation in vivo. Using an externally applied magnetic device, we have been able to enhance EPC localization at a site of common carotid artery injury. This technology could be more widely adapted to localize cells in other organs and may provide a useful tool for the systemic injection of cell therapies.

Effect of water extracts of Alpinia oxyphylla Miq. fruit on memory impairment in cerebral ischemia rats

Objective This report investigate the intervention effect of the water extract of Alpinia oxyphylla Miq. fruit (AOF)on memory impairment and the mechanism in cerebral ischemia rats. Methods 48 Rats were randomly divided into sham-operated group(n=12), ischemia group(n=12), AOF group Ⅰ( n= 12)and AOF group Ⅱ (n= 12). The model of transient cerebral ischemic/reperfusion was made by bilateral occlusion of common carotid arteries in rats and combination with reducing blood pressure with an abdominal injection of so-dium nitroprusside. Learning-memory ability was observed by step through test. The content of NO and the activi-ties of NOS were measured in hippocampus. Results In step through test,the latency in ischemia group[(143.8±65.2)s]significantly decreased, the number of errors (8.9±4.2 ) significantly increased compared with sham-operated group [latency: (257.2±67.1 ) s; number of errors: (1.7±1.1 ), P<0.01 ]. The latency in AOF group Ⅰ and AOF group Ⅱ[(186.5±46.2) s, (193.4±43.7 ) s ] significantly increased, the number of errors (6.1±2.9,5.2±2.1 ) significantly decreased compared with ischemia group(P<0.05, P<0.01). In hippocampus, the content of NO and the activities of NOS in ischemia group [(56.53±27.42) nmol/mg prot, (17.23±5.64) nmol/mg prot] significantly increased compared with sham-operated group[ (40.02±17.9 ) nmol/mg prot, ( 10.46±6.15)nmol/mg prot], and in AOF group Ⅰ and AOF group Ⅱ [content of NO:group Ⅰ (46.60 ±20. 26)nmol/mg prot,group Ⅱ (42.38±21.23) nmol/mg prot ;activities of NOS:group Ⅰ (13.98±5.13 ) nmol/mg pint,group Ⅱ(13.61±5.27) nmol/mg prot] significantly decreased compared with ischemia group(P<0.05). Conclu-sion AOF could significantly ameliorate the memory impairment in cerebral ischemic rats. Its effects may be in-volved in the decrease of content of NO and activities of NOS in hippocampus. Key words: Alpinia oxyphylla Miq. fruit; Cerebral ischemia; Memory impairment

Roles of Matrix Metalloproteinases in Flow-Induced Outward Vascular Remodeling

Sustained hemodynamic stresses, especially high blood flow, result in flow-induced outward vascular remodeling. Our previous study showed that macrophage depletion reduced flow-induced outward remodeling of the rat common carotid artery, indicating that macrophages are critical in flow-induced outward vascular remodeling. Macrophage is known to release proteinases, including matrix metalloproteinases (MMPs). Degradation and loosening of extracellular matrix by MMPs may facilitate vascular remodeling. Therefore, we assessed the functions of MMPs in flow-induced outward vascular remodeling by using the flow-augmented common carotid artery model in mice. We validated that ligation of the left common carotid artery increased blood flow and luminal diameter of the right common carotid artery without significant change in blood pressure of mice. To assess the functions of MMPs in flow-induced outward vascular remodeling, we used doxycycline (broad-spectrum MMP inhibitor), SB-3CT (selective MMP inhibitor), MMP-9 knockout mice, and MMP-12 knockout mice. Although there was only a trend for doxycycline treatment to reduce flow-induced outward vascular remodeling, SB-3CT treatment significantly reduced flow-induced outward vascular remodeling. In addition, flow-induced outward vascular remodeling was significantly reduced in MMP-9 knockout mice, but not in MMP-12 knockout mice. These data revealed that MMPs, especially MMP-9, are critical in flow-induced outward vascular remodeling.

Carnosine attenuates oxidative stress and apoptosis in transient cerebral ischemia in rats

Cerebral ischemia leads to cognitive decline and neuronal damage in the hippocampus. Reactive oxygen species (ROS) play an important role in the neuronal loss after cerebral ischemia and reperfusion injury. Carnosine has both antioxidant and neuroprotective effects against ROS. In the present study, the effects of carnosine on oxidative stress, apoptotic neuronal cell death and spatial memory following transient cerebral ischemia in rats were investigated. Transient ischemia was induced by occlusion of right common carotid artery of rats for 30 min and reperfusion for 24 h or 1 week. Rats received intraperitoneal injection of 250 mg/kg carnosine or saline 30 min prior to experiment. Determination of antioxidant enzyme activities was performed spectrophotometrically. To detect apoptotic cells, TUNEL staining was performed using an In Situ Cell Death Detection Kit. Carnosine treatment elicited a significant decrease in lipid peroxidation and increase in antioxidant enzyme activities in ischemic rat brains. The number of TUNEL-positive cells was decreased significantly in carnosine-treated group when compared with the ischemia-induction group. Carnosine treatment did not provide significant protection from ischemia induced deficits in spatial learning. The results show that carnosine is effective as a prophylactic treatment for brain tissue when it is administered before ischemia without affecting spatial memory.

Improvement of the Closed Cranial Window Model in Rats by Intracarotid Infusion of Signalling Molecules Implicated in Migraine

Intravital microscopy on a closed cranial window allows one to measure change in the diameter of cranial blood vessels after intravenous (i.v.) administration of pharmacodynamic substances. Putative targets being pursued in migraine are large vasodilating peptide molecules such as calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase polypeptide (PACAP)-38. High i.v. doses are required to study their craniovascular pharmacology. Unfortunately, this leads to a drop in blood pressure (BP) that subsequently causes blood vessels to dilate by autoregulation. Hence it is difficult to decipher what effect is caused by direct receptor agonist interaction or contributed by autoregulation. In the present study we infused substances with an ingenious indwelling catheter in the common carotid artery in rats. Intracarotidly seven-, 12- and 17-fold lower doses of CGRP, PACAP-38 and capsaicin were required, respectively, compared with i.v. infusion to induce the same dilation in dural artery. Dilating intracarotid (i.c.) doses caused no or a minimal fall in BP, whereas equi-responsive i.v. doses caused a marked BP reduction. The CGRP blocking potential of olcegepant was amplified by > 20 times on i.c. infusion. Pial artery responses to CGRP did not change with i.c. infusion, demonstrating that dilations after i.v. CGRP are mediated by autoregulation rather than through specific receptors. We applied CGRP topically, which induced concentration-dependent dural vasodilation, but no effect on pial artery or on BP. In conclusion, this new approach offers an improvement of the existing model by allowing more accurate assessment of effects of pharmaca on the cranial vasculature without inducing significant systemic effects.

White Matter Damage and Hippocampal Neurodegeneration Induced by Permanent Bilateral Occlusion of Common Carotid Artery in the Rat: Comparison between Wistar and Sprague-Dawley Strain

In order to reproduce chronic cerebral hypoperfusion as it occurs in human aging and Alzheimer's disease, we introduced permanent, bilateral occlusion of the common carotid arteries (BCCAO) in rats (Farkas et al, 2007). Here, we induced BCCAO in two different rat strains in order to determine whether there was a strain difference in the pathogenic response to BCCAO. Male Wistar and Sprague-Dawley (SD) rats (250-270 g) were subjected to BCCAO for three weeks. Klüver-Barrera and cresyl violet staining were used to evaluate white matter and gray matter damage, respectively. Wistar rats had a considerably higher mortality rate (four of 14 rats) as compared to SD rats (one of 15 rats) following BCCAO. Complete loss of pupillary light reflex occurred in all Wistar rats that survived, but loss of pupillary light reflex did not occur at all in SD rats. Moreover, BCCAO induced marked vacuolation in the optic tract of Wistar rats as compared to SD rats. In contrast, SD rats showed fewer CA1 hippocampal neurons than Wistar rats following BCCAO. These results suggest that the neuropathological process induced by BCCAO takes place in a region-specific pattern that varies according to the strain of rat involved.

Flow shear stress affects macromolecular accumulation through modulation of internal elastic lamina fenestrae

Background Internal elastic lamella and elastic lamellae serve as barriers for macromolecular accumulation in vascular wall. The function of internal elastic lamella in atherogenesis induced by shear stress has not been well understood yet. In the present study, internal elastic lamella remodeling and transmural accumulation of macromolecules in the arterial wall under altered shear stress were investigated. Methods The ligation of left distal carotid branches induced low shear stress in the left common carotid artery and high shear stress in the right common carotid artery of rats for 7 days. Fenestrae in internal elastic lamella were assessed by confocal microscopy. Horseradish peroxidase accumulation was determined by its transmural concentration profiles. Fibronectin expression was examined by immunohistologic staining and Western blotting. Findings Low shear stress significantly decreased the percentage of fenestrae area in internal elastic lamella from 15.35% to 8.03% in left common carotid artery, while high shear stress nearly had no influence in right common carotid artery. Comparing with less accumulation of horseradish peroxidase in right common carotid artery, horseradish peroxidase was significantly accumulated in the innermost part of the media, and fibronectin expression increased to 3.3-fold in left common carotid artery. Interpretation Our results suggested that shear stress alteration could influence the endothelial cell function as well as internal elastic lamella and elastic lamellae remodeling. Low shear stress decreased the permeability of internal elastic lamella and elastic lamellae by reducing fenestrae of them, which involved the enhanced fibronectin expression. Therefore, the increased accumulation of macromolecules in the arterial wall was observed. Our data supply new evidence on the mechanisms of atherogenesis induced by low shear stress.

The role of nitric oxide in the pathophysiology of intimal hyperplasia

Since its discovery, nitric oxide (NO) has emerged as a biologically important molecule and was even named Molecule of the Year by Science magazine in 1992. Specific to our interests, NO has been implicated in the regulation of vascular pathology. This review begins with a summary of the molecular biology of NO, from its discovery to the mechanisms of endogenous production. Next, we turn our attention to describing the arterial injury response of neointimal hyperplasia, and we review the role of NO in the pathophysiology of neointimal hyperplasia. Finally, we review the literature regarding NO-based therapies. This includes the development of inhalational-based NO therapies, systemically administered L-arginine and NO donors, NO synthase gene therapy, locally applied NO donors, and NO-releasing prosthetic materials. By reviewing the current literature, we emphasize the tremendous clinical potential that NO-based therapies can have on the development of neointimal hyperplasia.

Ketone bodies metabolism during ischemic and reperfusion brain injuries following bilateral occlusion of common carotid arteries in rats

To evaluate the in vivo alterations on ketone bodies metabolism after cerebral ischemia/reperfusion through an experimental model of brain ischemia induced by simple occlusion of common carotid arteries (CCAs) in Wistar rats. Forty-eight male Wistar rats were randomly distributed on two groups (S - Sham; T - Test) and further redistributed into four times sets of study. After bilateral occlusion of CCAs for 30 min, the animals of group T were allowed reperfusion for 0, 5, 10 and 15 min. Samples of cerebral tissue and systemic arterial blood were collected and the metabolites acetoacetate (ACT) and beta-hydroxybutyrate (BHB) were determined. Cerebral ACT and BHB levels increased significantly in Group T after 30 min of carotid occlusion (time 0). The highest brain ketone bodies (ACT+BHB) concentration was verified at 5 min of reperfusion, decreasing after 10 min of recirculation. Systemic ketone bodies levels increased similarly between test and sham groups. Group S demonstrated a significant increase in cerebral and systemic ACT and BHB concentrations mainly after 40-45 min of study. The partial transient acute global brain ischemia induced by the bilateral carotid occlusion in Wistar rats triggered ketogenesis probably due to a central stimulation of catecholamine secretion. There was an increased cerebral uptake of ketone bodies following brain ischemia, reaffirming these metabolites as alternative energy substrates under conditions of cerebral metabolic stress as well as its potential role on neuroprotection. The greatest changes in ketone bodies metabolism were verified at initial minutes of recirculation as a result of the reperfusion injury phenomenon.

A possible mechanism of unilateral hippocampal stroke after bilateral occlusion of the common carotid arteries in rats with different types of behavior

This article discusses the possible mechanisms of unilateral ischemic strokes arising in hippocampal field CA1 and the anterior dorsal nuclei of the thalamus after bilateral occlusion of the common carotid arteries in rats with different types of behavior.

Neuroprotective effects of growth hormone against hypoxic-ischemic brain injury in neonatal rats: 1H magnetic resonance spectroscopic study.

Using 1H-MRS, we evaluated the effects of growth hormone (GH) as a caspase inhibitor on hypoxic-ischemic injury in neonatal rat brains. The right common carotid arteries of rats were ligated, allowed to recover for 3 hr, and exposed to 8% oxygen for 2 hr. GH was given just prior to HI insult and animals were divided into four groups: control, intracerebroventricular (ICV), intracerebroventricular/intraperitoneal (ICV/IP), and intraperitoneal (IP). Localized in vivo 1H-MRS and TUNEL staining were performed 24 hr after HI injury. Lipid/N-acetyl aspartate (NAA) and lipid/creatine (Cr) ratios were used as apoptotic markers. Gross morphologic changes at 2 weeks were used to evaluate the effects of GH. The lipid/NAA ratio was lower in the ICV and ICV/IP groups than in the control, and the lipid/Cr ratio was lower in the ICV group than in the control. The number of TUNEL positive cells was decreased in the ICV and ICV/IP groups, and the degree of morphologic change indicative of brain injury was lower in the ICV group and somewhat lower in the ICV/IP group. The degree of morphologic change correlated with the lipid/NAA and lipid/Cr ratios. These findings suggest that GH exerts neuroprotective effects in cerebral hypoxic-ischemic injury.

End-to-End Microvascular Anastomosis in the Rat Carotid Artery Using Continuous Horizontal Mattress Sutures

This paper reports a continuous horizontal mattress suture technique with advantages such as decreased time for anastomosis, minimized anastomotic leakage, eversion around the vessel edges, and other advantages which the continuous anastomosis technique has. This technique was compared with the classical interrupted and classical continuous suture techniques on a total of 59 Sprague-Dawley rat common carotid arteries: Group 1 (n = 19), interrupted suture technique; Group 2 (n = 20), standard continuous technique, and Group 3 (n = 20), continuous horizontal mattress technique. Early (30 min) and late (21 days) patency rates, anastomosis time, leakage on clamp release, oozing duration, additional sutures needed, and total number of sutures placed were statistically compared between groups. Specimens were taken at the 21st day randomly, and light microscopy (LM), scanning electron microscopy (SEM), and angiographic studies were performed. Results revealed that the continuous mattress suture technique has the advantages of providing a water-tight anastomosis with less suture materials in a shorter time, and minimal intraluminal suture material which can incite thrombosis. On the other hand, a tendency to anastomotic stricture was found to be the sole disadvantage of this technique.

Chronic Brain Ischemia and Revascularization

Object. Vascular endothelial growth factor (VEGF) is a secreted mitogen associated with angiogenesis. The conceptual basis for therapeutic angiogenesis after plasmid human VEGF gene (phVEGF) transfer has been established in patients presenting with limb ischemia and myocardial infarction. The authors hypothesized that over-expression of VEGF using a gene transfer method combined with indirect vasoreconstruction might induce effective brain angiogenesis in chronic cerebral hypoperfusion, leading to prevention of ischemic attacks. Methods. A chronic cerebral hypoperfusion model induced by permanent ligation of both common carotid arteries in rats was used in this investigation. Seven days after induction of cerebral hypoperfusion, encephalomyosynangiosis (EMS) and phVEGF administration in the temporal muscle were performed. Fourteen days after treatment, the VEGF gene therapy group displayed numbers and areas of capillary vessels in temporal muscles that were 2.2 and 2.5 times greater, respectively, in comparison with the control group. In the brain, the number and area of capillary vessels in the group treated with the VEGF gene were 1.5 and 1.8 times greater, respectively, relative to the control group. Conclusions. In rat models of chronic cerebral hypoperfusion, administration of phVEGF combined with indirect vasoreconstructive surgery significantly increased capillary density in the brain. The authors' results indicate that administration of phVEGF may be an effective therapy in patients with chronic cerebral hypoperfusion, such as those with moyamoya disease.

Novel model of inflammatory neointima formation reveals a potential role of myeloperoxidase in neointimal hyperplasia

Atherosclerosis, which is characterized by neointima formation, is an inflammatory disease. However, there is no inflammatory product-elicited neointimal model to support the causal role of inflammation in atherogenesis. We reported previously that leukocyte-derived MPO induces vascular injury responses such as endothelial dysfunction. We now test the role of MPO in inflammatory neointima formation. We infused temporarily isolated rat common carotid arteries with MPO (200 nM) and incubated for 1 h. We found that although MPO itself did not induce any neointima formation 2 wk after treatment, in the presence of its substrate, hydrogen peroxide, MPO was able to elicit neointimal hyperplasia. We further confirmed that MPO-induced neointimal hyperplasia is mediated by its product, hypochlorous acid (HOCl). HOCl elicited apoptosis both in intima and media followed by vascular proliferative response and resulted in neointima formation with a heterogeneous cell population. Both histological and functional features of HOCl-treated vessels are similar to those in atherosclerotic lesions. To our knowledge, this is the first direct in vivo demonstration of neointimal formation induced by a product of the inflammatory cascade. The results suggest that MPO may be a mediator for pathological neointima growth. This novel neointimal model could be useful for studying inflammation and atherosclerosis.