induction of cerebral microhemorrhages in a rat model using lipopolysaccharide

Induction of Cerebral Microhemorrhages in a Rat Model Using Lipopolysaccharide

Administer LPS at a dose of 1 milligram per kilogram of body weight to 10-week-old male Sprague-Dawley rats by intraperitoneal injection. Then, return each rat to the home cage. Repeat the LPS injection after six hours and 16 hours.
Please note that injecting SD rats with LPS at a dose of 1 milligram per kilogram may result in a 5% mortality. The mortality could further increase in younger or older rats or pregnant female rats.
Return the rats to their cages after LPS injection, and provide ad libitum access to food and drink.

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All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
1. Materials
<ol>
	<li>Preparation of LPS injection&#8203;
	<ol>
		<li>Add 25 mL of distilled water to 25 mg of LPS powder derived from Salmonella typhimurium to a final concentration of 1 mg/mL. Store the injection in a sterile tube at 4 &#176;C. 
		CAUTION: LPS is toxic.</li>
	</ol>
	</li>
</ol>
2. Animals
<ol>
	<li>Administer LPS to male Sprague-Dawley (SD) rats, aged 10 weeks (average weight: 280 &#177; 20 g) by intraperitoneal injection. 
	CAUTION: If rats are purchased from another organization, then the adaptive phase should not be less than 7 days.</li>
</ol>
3. LPS Injections
<ol>
	<li>Inject LPS intraperitoneally into each rat at a dose of 1 mg/kg and return the rats to their home cage. 
	NOTE: Anesthesia is not necessary.</li>
	<li>Six hours later, inject the same dose of LPS injection into the rats.</li>
	<li>Sixteen hours later inject the same dose of LPS into the rats. 
	CAUTION: Injecting SD rats with LPS at a dose of 1 mg/kg may result in a 5% mortality rate. The mortality rate could further increase in younger or older rats or pregnant female rats.</li>
	<li>Return the rats to their cages after LPS injection and provide ad libitum access to food and drink. 
	NOTE: Rats will exhibit a distinct systemic inflammatory response, and thus the cages must remain clean throughout the experiment. Rats should be frequently (2x day) monitored for weight, general appearance, and attitude after the first LPS injection. If the rats start to exhibit a hunched posture, unwillingness to move, significant weight loss (&#62;20%), or porphyrin staining, they should be humanely euthanized before the 7-day study endpoint.</li>
</ol>

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>LPS</td>
			<td>Sigma-Aldrich</td>
			<td>L-2630</td>
			<td>for inflammation induction</td>
		</tr>
		<tr>
			<td>Phosphate buffer saline (PBS)</td>
			<td>Solarbio</td>
			<td>P1022</td>
			<td>a kind of buffer solution commonly used in experiment</td>
		</tr>
	</tbody>
</table>

Source: Li, D., et al. <a href="https://app.jove.com/v/58423">Sub-acute Cerebral Microhemorrhages Induced by Lipopolysaccharide Injection in Rats.</a> J. Vis. Exp. (2018).
This video demonstrates the process of inducing blood-brain barrier (BBB) disruption and cerebral microhemorrhages in a rat model using lipopolysaccharide (LPS). It highlights the sequence of immune responses that lead to increased BBB permeability and subsequent brain tissue damage.

All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.
1. ...

Begin by intraperitoneally injecting lipopolysaccharide (LPS), a bacterial component, into an adult rat.&#160;
LPS enters the bloodstream and binds to specific receptors on immune cells, triggering the release of inflammatory cytokines.
These cytokines reach the brain and activate the endothelial cells lining the cerebral blood vessels, increasing the expression of adhesion molecules and disrupting tight junction proteins, which increases the permeability of the blood-brain barrier (BBB).
Neutrophils adhere to the adhesion molecules and migrate across the BBB into the brain tissue.
Subsequently, the neutrophils release proteolytic enzymes and reactive oxygen species, which induce neuronal death and cause damage to brain tissue.
The cerebral blood vessels rupture, allowing blood cells to leak into the brain tissue.
Microglia then engulf these blood cells and convert hemoglobin to hemosiderin, a brown iron-containing pigment.
Hemosiderin deposits in the perivascular region mark the formation of cerebral microhemorrhages.

14 vues. Induction de microhémorragies cérébrales dans un modèle de rat à l’aide de lipopolysaccharide

Vidéo: Induction de microhémorragies cérébrales dans un modèle de rat à l’aide de lipopolysaccharide - Expérience

Rat Model of Widespread Cerebral Cortical Demyelination Induced by an Intracerebral Injection of Pro-Inflammatory Cytokines

Multiple sclerosis (MS) is the most common immune-mediated disease of the central nervous system (CNS) and progressively leads to physical disability and death, caused by white matter lesions in the spinal cord and cerebellum, as well as by demyelination in grey matter. Whilst conventional models of experimental allergic encephalomyelitis are suitable for the investigation of the cell-mediated inflammation in the spinal and cerebellar white matter, they fail to address grey matter pathologies. Here, we present the experimental protocol for a novel rat model of cortical demyelination allowing the investigation of the pathological and molecular mechanisms leading to cortical lesions. The demyelination is induced by an immunization with low-dose myelin oligodendrocyte glycoprotein (MOG) in an incomplete Freund&#39;s adjuvant followed by a catheter-mediated intracerebral delivery of pro-inflammatory cytokines. The catheter, moreover, enables multiple rounds of demyelination without causing injection-induced trauma, as well as the intracerebral delivery of potential therapeutic drugs undergoing a preclinical investigation. The method is also ethically favorable as animal pain and distress or disability are controlled and relatively minimal. The expected timeframe for the implementation of the entire protocol is around 8 - 10 weeks.

The protocol presented here allows the reproduction of a widespread grey matter demyelination of both cortical hemispheres in adult male Dark Agouti rats. The method comprises of intracerebral implantation of a catheter, subclinical immunization against myelin oligodendrocyte glycoprotein, and intracerebral injection of a pro-inflammatory cytokine mixture through the implanted catheter.

Modèle de rat de démyélinisation corticale cérébrale généralisée induite par une injection intracérébrale de cytokines pro-inflammatoires

Multiple sclerosis (MS) is the most common immune-mediated disease of the central nervous system (CNS) and progressively leads to physical disability and ...

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Neurosciences

Effects of Blast-induced Neurotrauma on Pressurized Rodent Middle Cerebral Arteries

Though there have been studies on the histopathological and behavioral effects of blast exposure, fewer have been dedicated to blast&#39;s cerebral vascular effects. Impact (i.e., non-blast) traumatic brain injury (TBI) is known to decrease pressure autoregulation in the cerebral vasculature in both humans and experimental animals. The hypothesis that blast-induced traumatic brain injury (bTBI), like impact TBI, results in impaired cerebral vascular reactivity was tested by measuring myogenic dilatory responses to reduced intravascular pressure in rodent middle cerebral arterial (MCA) segments from rats subjected to mild bTBI using an Advanced Blast Simulator (ABS) shock tube. Adult, male Sprague-Dawley rats were anesthetized, intubated, ventilated and prepared for Sham bTBI (identical manipulation and anesthesia except for blast injury) or mild bTBI. Rats were randomly assigned to receive Sham bTBI or mild bTBI followed by sacrifice 30 or 60 min post-injury. Immediately after bTBI, righting reflex (RR) suppression times were assessed, euthanasia at the time points post-injury was completed, the brain was harvested and the individual MCA segments were collected, mounted and pressurized. As the intraluminal pressure perfused through the arterial segments was reduced in 20 mmHg increments from 100 to 20 mmHg, MCA diameters were measured and recorded. With decreasing intraluminal pressure, MCA diameters steadily increased significantly above baseline in the Sham bTBI groups while MCA dilator responses were significantly reduced (p &#60; 0.05) in both bTBI groups as evidenced by the impaired, smaller MCA diameters recorded for the bTBI groups. In addition, RR suppression in the bTBI groups was significantly (p &#60; 0.05) higher than in the Sham bTBI groups. MCA&#39;s collected from the Sham bTBI groups exhibited typical vasodilatory properties to decreases in intraluminal pressure while MCA&#39;s collected following bTBI exhibited significantly impaired myogenic vasodilatory responses to reduced pressure that persisted for at least 60 min after bTBI.

Here, we present a protocol to describe methods for ex vivo vascular reactivity determination following a primary blast traumatic brain injury (bTBI) using isolated, pressurized, rodent middle cerebral arterial (MCA) segments. bTBI induction is accomplished using a shock tube, also known as an Advanced Blast Simulator (ABS) device.

Effets de neurotraumatologie induite par le souffle sur les rongeurs sous pression du milieu des artères cérébrales

Though there have been studies on the histopathological and behavioral effects of blast exposure, fewer have been dedicated to blast&#39;s cerebral ...

Laser-Induced Brain Injury in the Motor Cortex of Rats

A common technique for inducing stroke in experimental rodent models involves the transient (often denoted as MCAO-t) or permanent (designated as MCAO-p) occlusion of the middle cerebral artery (MCA) using a catheter. This generally accepted technique, however, has some limitations, thereby limiting its extensive use. Stroke induction by this method is often characterized by high variability in the localization and size of the ischemic area, periodical occurrences of hemorrhage, and high death rates. Also, the successful completion of any of the transient or permanent procedures requires expertise and often lasts for about 30 minutes. In this protocol, a laser irradiation technique is presented that can serve as an alternative method for inducing and studying brain injury in rodent models.
When compared to rats in the control and MCAO groups, the brain injury by laser induction showed reduced variability in body temperature, infarct volume, brain edema, intracranial hemorrhage, and mortality. Furthermore, the use of a laser-induced injury caused damage to the brain tissues only in the motor cortex unlike in the MCAO experiments where destruction of both the motor cortex and striatal tissues is observed.
Findings from this investigation suggest that laser irradiation could serve as an alternative and effective technique for inducing brain injury in the motor cortex. The method also shortens the time for completing the procedure and does not require expert handlers.

The protocol presented here shows a technique to create a rodent model of brain injury. The method described here uses laser irradiation and targets motor cortex.

Lésion cérébrale induite au laser dans le cortex moteur des rats

A common technique for inducing stroke in experimental rodent models involves the transient (often denoted as MCAO-t) or permanent (designated as MCAO-p) ...

Induction of Cerebral Microhemorrhages in a Rat Model Using Lipopolysaccharide

Transcription

Induction of Cerebral Microhemorrhages in a Rat Model Using Lipopolysaccharide