Name: assessment of blood-brain barrier permeability by intravenous infusion of fitc-labeled albumin in a mouse model of neurodegenerative disease
Uploaded: 2017-11-08T14:00:00
Description: Watch this Scientific Journal Video about Assessment of Blood-brain Barrier Permeability by Intravenous Infusion of FITC-labeled Albumin in a Mouse Model of Neurodegenerative Disease at JoVE.com

This work was supported by &#34;Fondazione Neuromed&#34; and funded by the Italian Ministry of Health &#34;Ricerca Corrente&#34; to V.M.

All procedures on animals were approved by the IRCCS Neuromed Animal Care Review Board and by &#34;Istituto Superiore di Sanit&#224;&#34; (permit number: 1163/2015- PR) and were in accordance with the guidelines of the EU Directive 2010/63/EU for animal experiments.
1. Preparation of FITC-albumin Solution to be Injected into Jugular Vein
NOTE: All experiments were carried out in manifest (11-week old) HD R6/2 mice and in age and gender-matched wild-type (WT) control l...

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The technique we describe here is primarily useful for detecting BBB leakage under brain disease conditions. BBB dysfunction is gaining attention as a common feature of diverse neurologic disorders4. We previously used this approach to describe the early derangement of BBB integrity in a mouse model of a rare neurodegenerative disease like HD6.
This method takes advantage of the relative simplicity and effectiveness of the procedure, which provid...

An erratum was issued for: <a href="https://www.jove.com/video/56389/assessment-blood-brain-barrier-permeability-intravenous-infusion-fitc">Assessment of Blood-brain Barrier Permeability by Intravenous Infusion of FITC-labeled Albumin in a Mouse Model of Neurodegenerative Disease</a>. One of the author&#39;s names was corrected from:
Maglione Vittorio
to:
Vittorio Maglione

An erratum was issued for: <a href="https://www.jove.com/video/56389/assessment-blood-brain-barrier-permeability-intravenous-infusion-fitc">Assessment of Blood-brain Barrier Permeability by Intravenous Infusion of FITC-labeled Albumin in a Mouse Model of Neurodegenerative Disease</a>. One of the author's names was corrected.

Erratum: Assessment of Blood-brain Barrier Permeability by Intravenous Infusion of FITC-labeled Albumin in a Mouse Model of Neurodegenerative Disease

Homeostasis within the central nervous system (CNS) is a prerequisite for the proper communication and function of the neuronal cells. The CNS parenchyma is tightly sealed off from the periphery by the endothelial blood-brain barrier (BBB), which represents the interface between the peripheral bloodstream and the brain and plays a pivotal role in the cross-talk between these two districts1,2. The BBB is a complex and dynamic three-dimensional structure mainly composed of specialized micro-vessel endothelial cells (ECs) linked to each other through intercellular junctional complexes - tight junctions (TJs)- and surrounded by pericytes, neuron endings and astrocyte foot processes1,2.
Under physiological conditions, the extremely low permeability of the intact BBB ensures the strict regulation of the transport of nutrients and other molecules into and out of the brain, and provides the CNS with a unique protection from changes occurring in the composition of the blood that might influence neural activity and against potential peripheral insults1,2,3.
Disruption of BBB integrity and its enhanced permeability has long been known to constitute a key feature for many neurological and neurodegenerative disorders4 including Huntington&#39;s Disease (HD)5,6, however, whether such a dysfunction is a causative phenomenon or a propagative event in the course of the disease is still unclear. The timing of BBB breakdown also remains elusive, however, emerging evidence by our group and others indicates that disrupted BBB integrity does not represent a late event in the disease progression, but rather an early step6,7,8, which may have long-term consequences.
With this in mind, it is important to precociously reveal BBB breakdown in neurodegeneration in order to develop strategies useful to predict disease progression and brain damage and to develop alternative and more targeted interventions capable of successfully mitigating the clinical consequences of such a disruption. Reliable imaging of BBB impairment is, therefore, of major importance in both experimental research and clinical management of brain diseases.
In this paper, we describe a successful and simple procedure for the evaluation of BBB permeability in a HD mouse model by using the high molecular weight fluorescein isothiocyanate labelled-albumin (FITC-albumin). Extravasation of FITC-albumin, which normally cannot cross the barrier, into the brain parenchyma was measured as an index of BBB leakage. This technique is readily adaptable to rats and to other pathological conditions characterized by cerebrovasculature impairment9,10.

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			<td>Albumin-fluorescin isothiocyanate conjiugate</td>
			<td>SIGMA</td>
			<td>A9771-100MG</td>
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			<td>Novus Biologicals</td>
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			<td>J1800AMNZ</td>
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			<td>Cover Slips 24 X 50 mm</td>
			<td>Thermo Scientific (DIAPATH)</td>
			<td>61050</td>
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			<td>Kilik Optimal Cutting Temperature (OCT) compound</td>
			<td>Bio Optica</td>
			<td>05-9801</td>
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			<td>VECTASHIELD Mounting Media</td>
			<td>VECTOR</td>
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			<td>Mounting media with DAPI</td>
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			<td>iNSu/Light Insulin Disposible Syringe</td>
			<td>RAYS Health &#38;Safety</td>
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			<td>30G 1/2&#34;</td>
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			<td>304000</td>
			<td>Needle for Insulin disposible Syringe</td>
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			<td>Scalpel Handle</td>
			<td>F.S.T.</td>
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			<td>#22 Disposable Scalpel blads</td>
			<td>F.S.T.</td>
			<td>10022-00</td>
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			<td>Fine Iris scissors 10.5 cm</td>
			<td>F.S.T.</td>
			<td>14094-11</td>
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			<td>Dumont Forceps #5745 45&#176; 0.10 x 0.06 mm</td>
			<td>F.S.T.</td>
			<td>11251-35</td>
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			<td>Graefe Forceps 10 cm</td>
			<td>F.S.T.</td>
			<td>11051-10</td>
			<td></td>
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		<tr>
			<td>Dumont Forceps #5 0.1 X 0.06 mm</td>
			<td>F.S.T.</td>
			<td>11251-20</td>
			<td></td>
		</tr>
		<tr>
			<td>Medical patch</td>
			<td>Medicalis</td>
			<td>34788</td>
			<td></td>
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			<td>Sterile disposable towel drape</td>
			<td>Dispotech</td>
			<td>TVO50VE</td>
			<td></td>
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			<td>Stereoscopic Microscope</td>
			<td>NIKON</td>
			<td>SMZ 745 T</td>
			<td></td>
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			<td>Optic Illuminator LED light (C-FLED2)</td>
			<td>NIKON</td>
			<td>1003167</td>
			<td>Optic Illuminator for Stereoscopic Micrscope</td>
		</tr>
		<tr>
			<td>Eclipse Ni-U Microscope</td>
			<td>Nikon</td>
			<td>932162</td>
			<td>Epifluorescence Microscope</td>
		</tr>
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			<td>Microscope digital Camera</td>
			<td>Nikon</td>
			<td>DS-Ri2</td>
			<td>Microscope camera</td>
		</tr>
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			<td>Intenslight</td>
			<td>Nikon</td>
			<td>C-HGFI</td>
			<td>Microscope lamp</td>
		</tr>
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			<td>NIS-Elements 64 bit</td>
			<td>Nikon</td>
			<td>AR 4.40.00</td>
			<td>Analysis Software</td>
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			<td>Electric Razor</td>
			<td>Gemei</td>
			<td>GM-3007</td>
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assessment of blood-brain barrier permeability by intravenous infusion of fitc-labeled albumin in a mouse model of neurodegenerative disease

Disruption of blood-brain barrier (BBB) integrity is a common feature for different neurological and neurodegenerative diseases. Although the interplay between perturbed BBB homeostasis and the pathogenesis of brain disorders needs further investigation, the development and validation of a reliable procedure to accurately detect BBB alterations may be crucial and represent a useful tool for potentially predicting disease progression and developing targeted therapeutic strategies.
Here, we present an easy and efficient procedure for evaluating BBB leakage in a neurodegenerative condition like that occurring in a preclinical mouse model of Huntington disease, in which defects in the permeability of BBB are clearly detectable precociously in the disease. Specifically, the high molecular weight fluorescein isothiocyanate labelled (FITC)-albumin, which is able to cross the BBB only when the latter is impaired, is acutely infused into a mouse jugular vein and its distribution in the vascular or parenchymal districts is then determined by fluorescence microscopy.
Accumulation of green fluorescent-albumin in the brain parenchyma functions as an index of aberrant BBB permeability and, when quantitated by using Image J processing software, is reported as Green Fluorescence Intensity.

Proper infusion of FITC-albumin into the jugular vein results in the extravasation of the green fluorescence tracer from the bloodstream into the brain parenchymawhen the BBB is compromised6. Under physiological conditions, distribution of infused fluorescent albumin is restricted to the inside of the brain blood vessels and no signal in the surrounding perivascular area and/or brain parenchyma is detectable (Figure 1A, micrographs on ...

Watch this Scientific Journal Video about Assessment of Blood-brain Barrier Permeability by Intravenous Infusion of FITC-labeled Albumin in a Mouse Model of Neurodegenerative Disease at JoVE.com

Assessment of Blood-brain Barrier Permeability by Intravenous Infusion of FITC-labeled Albumin in a Mouse Model of Neurodegenerative Disease

In this study, we present an easy and efficient procedure for evaluating the disruption of the blood-brain barrier under neurodegenerative conditions. To achieve our objective, we infused high molecular weight fluorescein isothiocyanate labelled (FITC)-albumin into mouse jugular vein and evaluated its leakage into the brain parenchyma by fluorescence microscopy.

Disruption of blood-brain barrier (BBB) integrity is a common feature for different neurological and neurodegenerative diseases. Although the interplay ...

The overall goal of this procedure is to assess the brain-blood barrier permeability in a mouse model of degenerative disorder by intrajugular injection of FITC-labeled albumin. This method can help answer the key questions in the study of brain homeostasis. It can be particularly useful to investigate any possible link between blood-brain barrier damage and neurodegeneration.The main advantage of this technique is that it is fast and easy to perform and can be applied, also, to larger animal models and to other neuro-pathological settings. Demonstrating the surgical procedure of intrajugular injection of FITC-albumen will be Luca Capocci. Salvatore Castaldo will demonstrate the histological sectioning of a brains.And Enrico Amico will demonstrate the procedure for micrograph acquisition. Begin by preparing FITC-albumen solution by dissolving FITC-albumen powder in phosphate buffered saline at 10 milligrams per milliliter. Lay out the autoclaved surgical instruments.Clean the surgical bench with 70%ethanol and place a surgical sterile disposable drape. Then set up the operating stereo microscope. After anesthetizing the mouse with an intraperitoneal injection of an appropriate does of ketamine xylazine solution, monitor animal sedation by giving a gentle toe pinch and ensuring the absence of the withdrawal reflex.Place the anesthetized mouse in a face-up supine position and fix the four legs and the tail on the surgical workbench with adhesive tape. After the mouse is secured, carefully shave the appropriate surgical margin on the neck and disinfect it with povidone-iodine solution in 70%ethanol. Dry the exposed shaved surface with cotton swabs.Next, after making a 1.5 centimeter long longitudinal incision in the mid-clavicular line, starting midway on the thorax and extending to just below the neck, carefully stretch apart connective tissue with forceps under microscopic observation to expose the external jugular vein. Ensure sufficient space on the right and on the left of the jugular vein to facilitate the insertion of the 30 and a half gauge needle for the infusion of the FITC-albumen solution. Inject 100 microliters of 10 milligrams per milliliter FITC-albumen in the right jugular vein over three minutes.This is the most critical step during the procedure. Incorrect insertion of the needle can cause irreversible damage of the vein wall and compromise the entire experiment. Fifteen minutes after injection, after euthanizing the mouse by decapitation, rapidly remove the brain from the skull and immerse it in a volume of pre-chilled isopentane, that is ten times that of the brain, for 15 minutes.Move the isopentane frozen brain into a pre-chilled tube and store it in a 80 degrees Celsius freezer until histological sectioning. Embed frozen brain in optimal cutting temperature compound prior to cryostat sectioning. Cut the brain into 20 micron thick sections with a cryostat and mount them onto microscope glass slides.Perform the FITC-albumin laminin co-staining by using a specific anti-laminin antibody, as previously described. Cover slip slides with mounting medium containing DAPI and leave the slide to dry overnight at four degrees Celsius in the dark. The next day, observe the fluorescence staining under a fluorescence microscope at 20 times magnification, equipped with both FITC and Cy3 filters.Turn on the fluorescence lamp about 10 minutes before use. Turn on the microscope, the connected computer and the digital camera. Run the image analysis software.Use the appropriate objective for optimal signal collection and spatial resolution and select appropriate filters. Acquire a minimum of four, 24-bit color exposures per brain slice. Analyze the fluorescence intensity for each single channel, using the freely available ImageJ software.The following representative fluorescence micrographs of brain cryosections show differential distribution of green fluorescent albumin under both physiological and pathological conditions. The red staining, shown here, represents the vascular marker, laminin, under physiological conditions and under conditions of blood-brain barrier compromise. These merged images show co-localization of green fluorescent albumin and laminin, along with DAPI staining of nuclei in the intact and compromised blood-brain barriers.This graph displays the quantification of the green fluorescence emitted by FITC-albumin, which is reported as the green fluorescence intensity in both healthy and compromised conditions. While attempting this procedure, it's important to remember to freshly prepare each single reagent and predispose the surgical bench. After watching this video, you may have a good understanding of how to assess the permeability of the blood-brain barrier in an animal model of neurodegenerative disease, by measuring the affixation of the green fluorescent albumin into brain parenchyma.

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Research

JoVE Journal

Neuroscience

Methods for Intravenous Self Administration in a Mouse Model

Animal models have been developed to study the reinforcing effects of drugs, including the intravenous self-administration (IVSA) paradigm. The advantages of using an IVSA paradigm to study the reinforcing properties of drugs of abuse such as cocaine include the fact that the drug is self-administered instead of experimenter-administered, the schedule of reinforcement can be altered, and accurate measurement of the quantities of drug consumed as well as the timing and pattern of IV injections can be obtained. Furthermore, the intravenous route of administration avoids potential confounds related to first pass metabolism or taste, and produces rapid increases in blood and brain drug levels. As outlined in this video, intravenous self-administration can be obtained without prior food restriction or prior drug training following careful catheter placement during surgery and meticulous daily catheter flushing and maintenance. Experimental procedures outlined in this paper include a description of animal housing and acclimation methods, operant training using sweetened milk solutions, and catheter implantation surgery.

The intravenous self-administration (IVSA) paradigm is considered to be the gold standard in examining the reinforcing properties of drugs of abuse in rodents. This manuscript outlines the experimental procedures and surgical techniques necessary to obtain reliable IVSA data. In particular, meticulous catheter implantation and maintenance are highlighted.

Animal models have been developed to study the reinforcing effects of drugs, including the intravenous self-administration (IVSA) paradigm. The advantages ...

Functional Neuroimaging Using Ultrasonic Blood-brain Barrier Disruption and Manganese-enhanced MRI

Although mice are the dominant model system for studying the genetic and molecular underpinnings of neuroscience, functional neuroimaging in mice remains technically challenging. One approach, Activation-Induced Manganese-enhanced MRI (AIM MRI), has been used successfully to map neuronal activity in rodents 1-5. In AIM MRI, Mn2+ acts a calcium analog and accumulates in depolarized neurons 6,7. Because Mn2+ shortens the T1 tissue property, regions of elevated neuronal activity will enhance in MRI. Furthermore, Mn2+ clears slowly from the activated regions; therefore, stimulation can be performed outside the magnet prior to imaging, enabling greater experimental flexibility. However, because Mn2+ does not readily cross the blood-brain barrier (BBB), the need to open the BBB has limited the use of AIM MRI, especially in mice.
One tool for opening the BBB is ultrasound. Though potentially damaging, if ultrasound is administered in combination with gas-filled microbubbles (i.e., ultrasound contrast agents), the acoustic pressure required for BBB opening is considerably lower. This combination of ultrasound and microbubbles can be used to reliably open the BBB without causing tissue damage 8-11.
Here, a method is presented for performing AIM MRI by using microbubbles and ultrasound to open the BBB. After an intravenous injection of perflutren microbubbles, an unfocused pulsed ultrasound beam is applied to the shaved mouse head for 3 minutes. For simplicity, we refer to this technique of BBB Opening with Microbubbles and UltraSound as BOMUS 12. Using BOMUS to open the BBB throughout both cerebral hemispheres, manganese is administered to the whole mouse brain. After experimental stimulation of the lightly sedated mice, AIM MRI is used to map the neuronal response.
To demonstrate this approach, herein BOMUS and AIM MRI are used to map unilateral mechanical stimulation of the vibrissae in lightly sedated mice 13. Because BOMUS can open the BBB throughout both hemispheres, the unstimulated side of the brain is used to control for nonspecific background stimulation. The resultant 3D activation map agrees well with published representations of the vibrissae regions of the barrel field cortex 14. The ultrasonic opening of the BBB is fast, noninvasive, and reversible; and thus this approach is suitable for high-throughput and/or longitudinal studies in awake mice.

A technique is described for broadly opening the blood-brain barrier in the mouse using microbubbles and ultrasound. Using this technique, manganese can be administered to the mouse brain. Because manganese is an MRI contrast agent that accumulates in depolarized neurons, this approach enables imaging of neuronal activity.

Although mice are the dominant model system for studying the genetic and molecular underpinnings of neuroscience, functional neuroimaging in mice remains ...

Olfactory Assays for Mouse Models of Neurodegenerative Disease

In many neurodegenerative diseases and particularly in Parkinson&#8217;s disease, deficits in olfaction are reported to occur early in the disease process and may be a useful behavioral marker for early detection. Earlier detection in neurodegenerative disease is a major goal in the field because this is when neuroprotective therapies have the best potential to be effective. Therefore, in preclinical studies testing novel neuroprotective strategies in rodent models of neurodegenerative disease, olfactory assessment could be highly useful in determining therapeutic potential of compounds and translation to the clinic. In the present study we describe a battery of olfactory assays that are useful in measuring olfactory function in mice. The tests presented in this study were chosen because they measure olfaction abilities in mice related to food odors, social odors, and non-social odors. These tests have proven useful in characterizing novel genetic mouse models of Parkinson&#8217;s disease as well as in testing potential disease-modifying therapies.

Impairment in olfactory function is a common feature in many neurodegenerative disorders including Parkinson, Alzheimer, and Huntington diseases. In the present article, we describe a set of tests for assessing olfaction discrimination and detection in mice that can be used to measure olfactory abilities in mouse models of neurodegenerative diseases.

In many neurodegenerative diseases and particularly in Parkinson&#8217;s disease, deficits in olfaction are reported to occur early in the disease process ...

An In Vivo Blood-brain Barrier Permeability Assay in Mice Using Fluorescently Labeled Tracers

Blood-brain barrier (BBB) is a specialized barrier that protects the brain microenvironment from toxins and pathogens in the circulation and maintains brain homeostasis. The principal sites of the barrier are endothelial cells of the brain capillaries whose barrier function results from tight intercellular junctions and efflux transporters expressed on the plasma membrane. This function is regulated by pericytes and astrocytes that together form the neurovascular unit (NVU). Several neurological diseases such as stroke, Alzheimer&#39;s disease (AD), brain tumors are associated with an impaired BBB function. Assessment of the BBB permeability is therefore crucial in evaluating the severity of the neurological disease and the success of the treatment strategies employed.
We present here a simple yet robust permeability assay that have been successfully applied to several mouse models both, genetic and experimental. The method is highly quantitative and objective in comparison to the tracer fluorescence analysis by microscopy that is commonly applied. In this method, mice are injected intraperitoneally with a mix of aqueous inert fluorescent tracers followed by anesthetizing the mice. Cardiac perfusion of the animals is performed prior to harvesting brain, kidneys or other organs. Organs are homogenized and centrifuged followed by fluorescence measurement from the supernatant. Blood drawn from the cardiac puncture just before perfusion serves for normalization purpose to the vascular compartment. The tissue fluorescence is normalized to the wet weight and serum fluorescence to obtain a quantitative tracer permeability index. For additional confirmation, the contralateral hemi-brain preserved for immunohistochemistry can be utilized for tracer fluorescence visualization purposes.

An In Vivo Blood-brain Barrier Permeability Assay in Mice Using Fluorescently Labeled Tracers

Here we present a mouse brain vascular permeability assay using intraperitoneal injection of fluorescent tracers followed by perfusion that is applicable to animal models of blood-brain barrier dysfunction. One hemi-brain is used for assessing permeability quantitatively and the other for tracer visualization/immunostaining. The procedure takes 5 - 6 h for 10 mice.

Blood-brain barrier (BBB) is a specialized barrier that protects the brain microenvironment from toxins and pathogens in the circulation and maintains ...

An In Vivo Assessment of Blood-Brain Barrier Disruption in a Rat Model of Ischemic Stroke

Ischemic stroke leads to vasogenic cerebral edema and subsequent primary brain injury, which is mediated through destruction of the blood-brain barrier (BBB). Rats with induced ischemic stroke were established and used as in vivo models to investigate the functional integrity of the BBB. Spectrophotometric detection of Evans blue (EB) in the brain samples with ischemic injury could provide reliable justification for the research and development of novel therapeutic modalities. This method generates reproducible results, and is applicable in any laboratory without a need for special equipment. Here, we present a visualized and technical guideline on the detection of the extravasation of EB following induction of ischemic stroke in rats.

An In Vivo Assessment of Blood-Brain Barrier Disruption in a Rat Model of Ischemic Stroke

The overall goal of this procedure is to provide a highly reproducible technique for in vivo assessment of the blood-brain barrier disruption in rat models of ischemic stroke.

Ischemic stroke leads to vasogenic cerebral edema and subsequent primary brain injury, which is mediated through destruction of the blood-brain barrier ...

A Human Blood-Brain Interface Model to Study Barrier Crossings by Pathogens or Medicines and Their Interactions with the Brain

The early screening of nervous system medicines on a pertinent and reliable in cellulo BBB model for their penetration and their interaction with the barrier and the brain parenchyma is still an unmet need. To fill this gap, we designed a 2D in cellulo model, the BBB-Minibrain, by combining a polyester porous membrane culture insert human BBB model with a Minibrain formed by a tri-culture of human brain cells (neurons, astrocytes and microglial cells). The BBB-Minibrain allowed us to test the transport of a neuroprotective drug candidate (e.g., Neurovita), through the BBB, to determine the specific targeting of this molecule to neurons and to show that the neuroprotective property of the drug was preserved after the drug had crossed the BBB. We have also demonstrated that BBB-Minibrain constitutes an interesting model to detect the passage of virus particles across the endothelial cells barrier and to monitor the infection of the Minibrain by neuroinvasive virus particles. The BBB-Minibrain is a reliable system, easy to handle for researcher trained in cell culture technology and predictive of the brain cells phenotypes after treatment or insult. The interest of such in cellulo testing would be twofold: introducing derisking steps early in the drug development on the one hand and reducing the use of animal testing on the other hand.

Here we present a protocol describing the setting of an in cellulo BBB (Blood brain barrier)-Minibrain polyester porous membrane culture insert system in order to evaluate the transport of biomolecules or infectious agents across a human BBB and their physiological impact on the neighboring brain cells.

The early screening of nervous system medicines on a pertinent and reliable in cellulo BBB model for their penetration and their interaction with the ...

A Benchtop Approach to the Location Specific Blood Brain Barrier Opening using Focused Ultrasound in a Rat Model

Stereotaxic surgery is the gold standard for localized drug and gene delivery to the rodent brain. This technique has many advantages over systemic delivery including precise localization to a target brain region and reduction of off target side effects. However, stereotaxic surgery is highly invasive which limits its translational efficacy, requires long recovery times, and provides challenges when targeting multiple brain regions. Focused ultrasound (FUS) can be used in combination with circulating microbubbles to transiently open the blood brain barrier (BBB) in millimeter sized regions. This allows intracranial localization of systemically delivered agents that cannot normally cross the BBB. This technique provides a noninvasive alternative to stereotaxic surgery. However, to date this technique has yet to be widely adopted in neuroscience laboratories due to the limited access to equipment and standardized methods. The overall goal of this protocol is to provide a benchtop approach to FUS BBB opening (BBBO) that is affordable and reproducible and can therefore be easily adopted by any laboratory.

Focused ultrasound with microbubble agents can open the blood brain barrier focally and transiently. This technique has been used to deliver a wide range of agents across the blood brain barrier. This article provides a detailed protocol for the localized delivery to the rodent brain with or without MRI guidance.

Stereotaxic surgery is the gold standard for localized drug and gene delivery to the rodent brain. This technique has many advantages over systemic ...

Induction and Assessment of Levodopa-induced Dyskinesias in a Rat Model of Parkinson's Disease

Levodopa (L-DOPA) remains the gold-standard therapy used to treat Parkinson&#39;s disease (PD) motor symptoms. However, unwanted involuntary movements known as L-DOPA-induced dyskinesias (LIDs) develop with prolonged use of this dopamine precursor.&#160;It is estimated that the incidence of LIDs escalates to approximately 90% of individuals with PD within 10&#8211;15 years of treatment. Understanding the mechanisms of this malady and developing both novel and effective anti-dyskinesia treatments requires consistent and accurate modeling for pre-clinical testing of therapeutic interventions. A detailed method for reliable induction and comprehensive rating of LIDs following 6-OHDA-induced nigral lesioning in a rat model of PD is presented here. Dependable LID assessment in rats provides a powerful tool that can be readily utilized across laboratories to test emerging therapies focused on reducing or eliminating this common treatment-induced burden for individuals with PD.

Induction and Assessment of Levodopa-induced Dyskinesias in a Rat Model of Parkinson&#039;s Disease

This article describes methods to induce and evaluate levodopa-induced dyskinesias in a rat model of Parkinson&#39;s disease. The protocol offers detailed information regarding the intensity and frequency of a range of dyskinetic behaviors, both dystonic and hyperkinetic, providing a reliable tool to test treatments targeting this unmet medical need.

Levodopa (L-DOPA) remains the gold-standard therapy used to treat Parkinson&#39;s disease (PD) motor symptoms. However, unwanted involuntary movements ...

Constipation Assays in &lt;em&gt;Drosophila&lt;/em&gt; Flies

Measuring Constipation in a Drosophila Model of Parkinson's Disease

Non-motor symptoms in Parkinson's disease (PD) are common, difficult to treat, and significantly impair quality of life. One prevalent non-motor symptom is constipation, which can precede the diagnosis of PD by years or even decades. Constipation has been underexplored in animal models of PD and lacks specific therapies. This assay utilizes a Drosophila model of PD in which human alpha-synuclein is expressed under a pan-neuronal driver. Flies expressing alpha-synuclein develop the hallmark features of PD: the loss of dopaminergic neurons, motor impairment, and alpha-synuclein inclusions.
This protocol outlines a method for studying constipation in these flies. Flies are placed on fly food with a blue color additive overnight and then transferred to standard food the following day. They are subsequently moved to new vials with standard fly food every hour for 8 h. Before each transfer, the percentage of blue-colored fecal spots compared to the total fecal spots on the vial wall is calculated. Control flies that lack alpha-synuclein expel all the blue dye hours before flies expressing alpha-synuclein. Additionally, the passage of blue-colored food from the gut can be monitored with simple photography. The simplicity of this assay enables its use in forward genetic or chemical screens to identify modifiers of constipation in Drosophila.

Author Spotlight: Exploring Non-Motor Symptoms in Parkinson's Disease 

This protocol presents an assay for modeling constipation in an alpha-synuclein based Drosophila model of Parkinson's disease.

Non-motor symptoms in Parkinson's disease (PD) are common, difficult to treat, and significantly impair quality of life. One prevalent non-motor symptom ...

Transendothelial Resistance Measurement to Assess Cell Barrier Integrity

Barrier Functional Integrity Recording on bEnd.3 Vascular Endothelial Cells via Transendothelial Electrical Resistance Detection

The blood-brain barrier (BBB) is a dynamic physiological structure composed of microvascular endothelial cells, astrocytes, and pericytes. By coordinating the interaction between restricted transit of harmful substances, nutrient absorption, and metabolite clearance in the brain, the BBB is essential in preserving central nervous system homeostasis. Building in vitro models of the BBB is a valuable tool for exploring the pathophysiology of neurological disorders and creating pharmacological treatments. This study describes a procedure for creating an in vitro monolayer BBB cell model by seeding bEnd.3 cells into the upper chamber of a 24-well plate. To assess the integrity of cell barrier function, the conventional epithelial cell voltmeter was used to record the transmembrane electrical resistance of normal cells and CoCl2-induced hypoxic cells in real-time. We anticipate that the above experiments will provide effective ideas for the creation of in vitro models of BBB and drugs to treat disorders of central nervous system diseases.

Author Spotlight: Applications of TEER Detection to Assess Cell Barrier Integrity 

This protocol describes a dependable and efficient in vitro model of the brain blood barrier. The method uses mouse cerebral vascular endothelial cells bEnd.3 and measures transmembrane electrical resistance.

The blood-brain barrier (BBB) is a dynamic physiological structure composed of microvascular endothelial cells, astrocytes, and pericytes. By coordinating ...