Name: assessment of hippocampal dendritic complexity in aged mice using the golgi-cox method
Uploaded: 2017-06-22T13:00:00
Description: Watch this Scientific Journal Video about Assessment of Hippocampal Dendritic Complexity in Aged Mice Using the Golgi-Cox Method at JoVE.com

This work was supported by a pilot grant under NIH P20 GM109005 (A.R.A.) and by the Center for Translational Neuroscience IDeA program award P30 GM110702.

Experiments were conducted in accordance with the ethical standards approved by the Institutional Animal Care and Use Committee at UAMS.
1. Animals and 5-Fu Injection Paradigm
<ol>
	<li>Purchase 6-month-old male C57Bl6/J wild-type mice and house them under a constant 12 h light/dark cycle until they reach 1 year of age.</li>
	<li>Dilute the 5-Fu in 0.9% sterile saline. Use 60 mg/kg as the required dose per mouse.</li>
	<li>Give the intraperitoneal injections of the 5-Fu (once per wee...

<ol>
	<li>Stuart, G. J., Spruston, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dendritic+integration:+60+years+of+progress.">Dendritic integration: 60 years of progress.</a> Nat Neurosci. 18 (12), 1713-1721 (2015).</li><li>Jan, Y. N., Jan, L. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Branching+out:+mechanisms+of+dendritic+arborization.">Branching out: mechanisms of dendritic arborization.</a> Nat Rev Neurosci. 11 (5), 316-328 (2010).</li><li>Kulkarni, V. A., Firestein, B. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+dendritic+tree+and+brain+disorders.">The dendritic tree and brain disorders.</a> Mol Cell Neurosci. 50 (1), 10-20 (2012).</li><li>Kasai, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+Dynamics+of+Dendritic+Spines+in+Memory+and+Cognition.">Structural Dynamics of Dendritic Spines in Memory and Cognition.</a> Trends Neurosci. 33 (3), 121-129 (2010).</li><li>von Bohlen Und Halbach, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+and+function+of+dendritic+spines+within+the+hippocampus.">Structure and function of dendritic spines within the hippocampus.</a> Ann Anat. 191 (6), 518-531 (2009).</li><li>Wayman, G. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activity-dependent+dendritic+arborization+mediated+by+CaM-kinase+I+activation+and+enhanced+CREB-dependent+transcription+of+Wnt-2.">Activity-dependent dendritic arborization mediated by CaM-kinase I activation and enhanced CREB-dependent transcription of Wnt-2.</a> Neuron. 50 (6), 897-909 (2006).</li><li>Bourne, J. N., Harris, K. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Balancing+structure+and+function+at+hippocampal+dendritic+spines.">Balancing structure and function at hippocampal dendritic spines.</a> Ann Rev Neurosci. 31, 47-67 (2008).</li><li>Lai, K. O., Ip, N. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+plasticity+of+dendritic+spines:+the+underlying+mechanisms+and+its+dysregulation+in+brain+disorders.">Structural plasticity of dendritic spines: the underlying mechanisms and its dysregulation in brain disorders.</a> Biochim Biophys Acta. 1832 (12), 2257-2263 (2013).</li><li>Harris, K. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure,+development,+and+plasticity+of+dendritic+spines.">Structure, development, and plasticity of dendritic spines.</a> Current Op Neurobiol. 9 (3), 343-348 (1999).</li><li>Harris, K. M., Kater, S. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dendritic+spines:+cellular+specializations+imparting+both+stability+and+flexibility+to+synaptic+function.">Dendritic spines: cellular specializations imparting both stability and flexibility to synaptic function.</a> Ann Rev Neurosci. 17, 341-371 (1994).</li><li>Leuner, B., Shors, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stress,+anxiety,+and+dendritic+spines:+what+are+the+connections.">Stress, anxiety, and dendritic spines: what are the connections.</a> Neuroscience. 251, 108-119 (2013).</li><li>Harris, K. M., Fiala, J. C., Ostroff, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+changes+at+dendritic+spine+synapses+during+long-term+potentiation.">Structural changes at dendritic spine synapses during long-term potentiation.</a> Philos Trans R Soc Lond B Biol Sci. 358 (1432), 745-748 (2003).</li><li>Kasai, H., Matsuzaki, M., Noguchi, J., Yasumatsu, N., Nakahara, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure-stability-function+relationships+of+dendritic+spines.">Structure-stability-function relationships of dendritic spines.</a> Trends Neurosci. 26 (7), 360-368 (2003).</li><li>Das, G., Reuhl, K., Zhou, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Golgi-Cox+method.">The Golgi-Cox method.</a> Methods Mol Biol. 1018, 313-321 (2013).</li><li>Koyama, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+unending+fascination+with+the+Golgi+method.">The unending fascination with the Golgi method.</a> OA Anat. 1 (3), 24 (2013).</li><li>Pasternak, J. F., Woolsey, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+"selectivity"+of+the+Golgi-Cox+method.">On the "selectivity" of the Golgi-Cox method.</a> J Comp Neurol. 160 (3), 307-312 (1975).</li><li>Friedland, D. R., Los, J. G., Ryugo, D. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+modified+Golgi+staining+protocol+for+use+in+the+human+brain+stem+and+cerebellum.">A modified Golgi staining protocol for use in the human brain stem and cerebellum.</a> J Neurosci Methods. 150 (1), 90-95 (2006).</li><li>Rosoklija, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+Golgi+methods+for+impregnation+of+brain+tissue+from+humans+and+monkeys.">Optimization of Golgi methods for impregnation of brain tissue from humans and monkeys.</a> J Neurosci Methods. 131 (1-2), 1-7 (2003).</li><li>de Castro, F., Lopez-Mascaraque, L., De Carlos, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cajal:+lessons+on+brain+development.">Cajal: lessons on brain development.</a> Brain Res Rev. 55 (2), 481-489 (2007).</li><li>Gabbott, P. L., Somogyi, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+"single"+section+Golgi-impregnation+procedure:+methodological+description.">The "single" section Golgi-impregnation procedure: methodological description.</a> J Neurosci Methods. 11 (4), 221-230 (1984).</li><li>Zaqout, S., Kaindl, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Golgi-Cox+staining+step+by+step.">Golgi-Cox staining step by step.</a> Front Neuroanat. 10 (38), (2016).</li><li>. Vibroslice NVSL &amp; Vibroslice NVSLM123 Available from: <a target="_blank" href="https://www.wpiinc.com/clientuploads/pdf/NVSL_NVSLM1_IM.pdf">https://www.wpiinc.com/clientuploads/pdf/NVSL_NVSLM1_IM.pdf</a> (2000)</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Neurolucida 11.03. , (2017).</li><li>Sholl, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dendritic+organization+in+the+neurons+of+the+visual+and+motor+cortices+of+the+cat.">Dendritic organization in the neurons of the visual and motor cortices of the cat.</a> J Anat. 87 (4), 387-406 (1953).</li><li>Pillai, A. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dendritic+morphology+of+hippocampal+and+amygdalar+neurons+in+adolescent+mice+is+resilient+to+genetic+differences+in+stress+reactivity.">Dendritic morphology of hippocampal and amygdalar neurons in adolescent mice is resilient to genetic differences in stress reactivity.</a> PLoS ONE. 7 (6), (2012).</li><li>Morley, B. J., Mervis, R. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dendritic+spine+alterations+in+the+hippocampus+and+parietal+cortex+of+alpha7+nicotinic+acetylcholine+receptor+knockout+mice.">Dendritic spine alterations in the hippocampus and parietal cortex of alpha7 nicotinic acetylcholine receptor knockout mice.</a> Neuroscience. 233, 54-63 (2013).</li><li>Titus, A. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypobaric+hypoxia-induced+dendritic+atrophy+of+hippocampal+neurons+is+associated+with+cognitive+impairment+in+adult+rats.">Hypobaric hypoxia-induced dendritic atrophy of hippocampal neurons is associated with cognitive impairment in adult rats.</a> Neuroscience. 145 (1), 265-278 (2007).</li><li>Groves, T. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=5-Fluorouracil+chemotherapy+upregulates+cytokines+and+alters+hippocampal+dendritic+complexity+in+aged+mice.">5-Fluorouracil chemotherapy upregulates cytokines and alters hippocampal dendritic complexity in aged mice.</a> Behavioral Brain Research. 316, 215-224 (2017).</li><li>Risher, W. C., Ustunkaya, T., Singh Alvarado, J., Eroglu, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+Golgi+analysis+method+for+efficient+and+unbiased+classification+of+dendritic+spines.">Rapid Golgi analysis method for efficient and unbiased classification of dendritic spines.</a> PloS One. 9 (9), (2014).</li><li>Kaufmann, W. E., Moser, H. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dendritic+anomalies+in+disorders+associated+with+mental+retardation.">Dendritic anomalies in disorders associated with mental retardation.</a> Cerebral cortex. 10 (10), 981-991 (2000).</li><li>Kulkarni, V. A., Firestein, B. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+dendritic+tree+and+brain+disorders.">The dendritic tree and brain disorders.</a> Mol Cell Neurosci. 50 (1), 10-20 (2012).</li></ol>

Compared to more modern techniques, the Golgi-Cox method has several advantages that make it the preferred method for examining spine morphology: 1) The staining can be used for essentially any tissue, 2) A basic light microscope setup is all that is needed to acquire Golgi-based images, 3) The Golgi-Cox imaging is faster than confocal imaging, and 4) Golgi stained sections are viable for several months to years longer than samples that are fluorescently-labeled. Even with these advantages, the Golgi-Cox method still has...

Dendrites are the largest portion of neurons that receive and process presynaptic input1. Their dendritic processes have a complex geometry, where the proximal branches have a larger diameter than the distal branches. As dendrites develop, they form several connections with other neurons in a process referred to as dendritic arborization. The extent and pattern of this branching determines the amount of synaptic inputs that a dendrite can adequately process2.
Dendritic arborization is a necessary process for activity-dependent plasticity and proper development of neuronal circuits. Extension, retraction, branching, and synaptogenesis are intricate processes that include intrinsic genetic programs and influences from extrinsic factors. The morphological and branching variations of the neuronal dendrites within the hippocampus are implicated in cognition and memory formation3,4. The alterations in dendritic complexity are associated with pathophysiological and behavioral changes5. Abnormalities are related to several disease states, including Fragile X Syndrome and Down Syndrome6.
Dendritic spines are the specialized subcellular compartments of the dendritic arbors that receive excitatory input within the central nervous system. There are three morphological classes of dendritic spines, with the name of each class based on their size and shape: 1) mushroom spines, which have complex postsynaptic densities with more glutamate receptors than other spines7; 2) stubby spines, which lack a stem; and 3) thin spines, which consist of a protracted, narrow stem and a globular head8. The dendritic spine volume is used in part to define them, with thin spines generally smaller (0.01 &#181;m3) compared to mushroom spines (0.8 &#181;m3)9,10. The spines stabilize with maturation. For example, the thin spines either retract after a few days or develop into mushroom spines. Alternatively, the mushroom spines are relatively stable and can survive for an extended period.The strength of the neuronal connections is thought to be based on the number of spines and/or their volume11,12,13.
The classical Golgi staining method and its more modern variations have all been useful for examining the dendritic spine morphology and density. One unique aspect of the Golgi staining is that it randomly stains about 5% of the total neurons, which allows for the tracing of individual neurons14,15. Although the exact mechanism in which the Golgi method stains individual neurons is still unknown, the principle of the method is based on the crystallization of silver chromate (Ag2CrO4)16,17. There are three main types of the Golgi method: the rapid Golgi, the Golgi-Cox, and the Golgi-Kopsch18,19. All three methods start with an initial incubation phase in chromium salts for several days to months, but there are certain key differences between them. The rapid Golgi uses osmium tetroxide in the first step, whereas the Golgi-Kopsch includes paraformaldehyde. The staining in both the rapid-Golgi and the Golgi-Kopsch is followed by an incubation in a 1-2% silver nitrate solution for about 7 days. The Golgi-Cox method uses mercuric chloride and potassium dichromate instead of silver nitrate and has an impregnation time of 2-4 weeks. The tissues are then sectioned and quickly placed in a diluted ammonia solution, followed by a photographic fixer to remove salts. Of the three types, the Golgi-Cox method is thought to be the best at staining the dendritic arbors without much background interference, in part, because the crystal artifacts do not occur on the surface of the tissue (unlike in the rapid Golgi method)17,20,21.
The present method is a slight variation of the protocol provided with a commercial Golgi staining kit, and was designed to assess how a relatively low dose of the 5-Fu would affect the dendritic morphological characteristics and the spine density. Any data acquired could provide further insight into how chemotherapeutic treatment affects the neuronal circuitry.

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			<td height="21" style="height:21px;width:216px;">25 mL serological pipette</td>
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			<td height="21" style="height:21px;width:216px;">C57Bl/6 Male Mice&#160;</td>
			<td style="width:207px;">The Jackson Laboratory&#160;</td>
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			<td height="84" style="height:84px;width:216px;">Axio Imager 2</td>
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assessment of hippocampal dendritic complexity in aged mice using the golgi-cox method

Dendritic spines are the protuberances from the neuronal dendritic shafts that contain&#160; excitatory synapses. The morphological and branching variations of the neuronal dendrites within the hippocampus are implicated in cognition and memory formation. There are several approaches to Golgi staining, all of which have been useful for determining the morphological characteristics of dendritic arbors and produce a clear background. The present Golgi-Cox method, (a slight variation of the protocol that is provided with a commercial Golgi staining kit), was designed to assess how a relatively low dose of the chemotherapeutic drug 5-flurouracil (5-Fu) would affect dendritic morphology, the number of spines, and the complexity of arborization within the hippocampus. The 5-Fu significantly modulated the dendritic complexity and decreased the spine density throughout the hippocampus in a region-specific manner. The data presented show that the Golgi staining method effectively stained the mature neurons in the CA1, the CA3, and the dentate gyrus (DG) of the hippocampus. This protocol reports the details for each step so that other researchers can reliably stain tissue throughout the brain with high quality results and minimal troubleshooting.

The effects of the 5-Fu treatment on the dendritic arborization and complexity in the hippocampus of Golgi-stained brain sections were quantified and traced using a commercially available imaging software. After tracing, the dendritic arborization, the spine density, and the spine morphology were analyzed using Sholl analysis and the dendritic complexity index (DCI). Sholl analysis is a quantitative analytical method that can be used to determine the dendritic arbor morphology<sup class="...

Watch this Scientific Journal Video about Assessment of Hippocampal Dendritic Complexity in Aged Mice Using the Golgi-Cox Method at JoVE.com

Assessment of Hippocampal Dendritic Complexity in Aged Mice Using the Golgi-Cox Method

Here we present a Golgi-Cox protocol in extensive detail. This reliable tissue stain method allows for a high-quality assessment of the cytoarchitecture in the hippocampus, and throughout the entire brain, with minimal troubleshooting.

Dendritic spines are the protuberances from the neuronal dendritic shafts that contain&#160; excitatory synapses. The morphological and branching ...

The overall goal of this methodology is to properly Golgi stain brain tissue in order to examine and quantify dendritic morphology and complexity. This method can help answer key questions in neuroscience. Since Golgi staining only stains a small subset of cells, this technique could be used to trace the structure of neurons.The main advantage of this technique is that brain sections can be easily stained without risk to them drying out or falling off during any of the washing steps. Demonstrating the procedure will be Fred Kiffer, Tyler Alexander and Julie Anderson, graduate students in Dr.Allen's laboratory. Begin by immersing freshly harvested, unfixed rodent half brains in five milliliters or mercuric chloride-based solution.As mercuric chloride solution is light sensitive, cover the tube with foil. Store the samples in the dark at room temperature. The following day, slowly decant the solution into a temporary container before properly disposing of it in a biohazard waste container.Add five milliliters of fresh mercuric chloride solution and ensure that the brains are immersed. Return the samples to the dark at room temperature for 13 more days. After 14 days, prepare post-impregnation buffer by adding 30 grams of powered post-impregnation buffer to 90 milliliters of distilled or deionized water, DH2O.Fill each well of the six-well plate with 6.5 milliliters of the post-impregnation buffer, one well per brain. Then, remove the mercuric chloride solution from the brain tissue as before. Rinse the tissue with DH2O, then transfer the tissue to the six-well plates with post-impregnation buffer.Cover the plates with foil and store at room temperature in the dark. The next day, aspirate and replace the post-impregnation buffer. Re-cover the plate and store in a four degree Celsius fridge.Prepare two or three 12-well plates per brain by first labeling the plates on their lids with numbers in ascending order from left to right and up to down. Add the identification number of the brain sectioned. Pipette two milliliters of 1X PBS into each well of each plate, then set up the stage and turn on the vibratome.Then, put tape on the tissue block of the specimen holder and add a little cyanoacrylate glue on top. Remove a brain from the six-well plate and place it on a plastic or glass dish. Use a stainless steel double edged blade to cut the cerebellum caudally, making sure that the portion of the cerebellum remaining on the brain is flat.Then, place the flat surface of the remaining cerebellum on the glue. After the glue is dry, place the specimen holder with the tissue into the specimen bath. Place the specimen bath on the vibratome and cover the tissue sample in PBS.Then, attach the blade to the blade holder of the vibratome and slowly lower the blade into the specimen bath until it is fully submerged and slightly below the top of the tissue. Next, set the vibratome speed to seven, the amplitude to six and the cutting angle to 12 degrees. Start the vibration and cut 200-micron sections.Use a large paint brush to move the tissue sections from the specimen bath into each designated well of the 12-well plates. Continue to cut the tissue until the desired number of tissue sections is reached. After sectioning, use a transfer pipette to aspirate the PBS from the wells of the 12-well plate, then add two milliliters of PBS-T and wash for 30 minutes with agitation.Close to the end of the wash period, dilute three parts ammonium hydroxide solution with five parts DH2O. Then, after removing the PBS-T, add the diluted ammonium hydroxide solution. Protect from light using foil and stain the sections for 19 to 21 minutes.Then, after safely removing the ammonium hydroxide solution, add post-staining buffer. Protect with foil and stain for another 19 to 21 minutes. Finally, rinse the sections in PBS-T three times for five to 10 minutes each time.Mount the sections on 1%gelatin coated slides with the large paint brush. Allow them to dry for 20 to 30 minutes at room temperature, then place them in a Coplin Jar and leave overnight. Remove the slides from the Coplin Jar and place them in a plastic rack in the fume hood.Place in a staining dish containing 100%ethanol for five minutes. Dehydrate the sections through two further five-minute ethanol washes. Next, place the slides in a glass rack and use a metal handle to lower the rack into a glass staining dish containing 99%xylene.Wash the slides in two changes of xylene for five minutes each. After the time for the second wash has elapsed, remove the slides from the xylene one at a time and quickly cover the tissue with approximately 0.25 milliliters of mounting media. Next, take a slide cover and lay it over the media.Push any trapped air bubbles underneath the slide covers to the edge with a blunt object, such as the end of paint brush. Place the slides in an area out of direct sunlight and allow them to dry for two to three days. After drying, proceed to image acquisition using a microscope and analysis with the appropriate software.This bright field image shows a Golgi-stained neuron that meets the criteria for imaging and further analysis. All three spine types can easily be seen. Staining is consistent across the entire length of the dendrite and the dendrite is isolated from other neurons.This figure shows that Golgi stained neurons within the Dentate Gyrus showed decreased length at the fourth and sixth order following 5-fluorouracil treatment compared to the saline-treated group. Golgi staining can be used to detect significant differences in spine density. In the CA1 apical pyramidal dendrites, 5-fluorouracil administration to live mice significantly decreased spine density.In the basal dendrites, there were no significant changes in the overall density of spines. Sholl Analysis of CA1 apical pyramidal dendrites revealed that 5-fluorouracil treatment significantly decreased dendritic arborization at distances between 40 to 160 microns away from the soma. In the basal dendrites, the 5-fluorouracil treatment decreased the dendritic arborization at 30 to 110 microns away from the soma.Once mastered, this technique, accounting for both the Golgi staining process and mounting, cleaning and covering can be done in three hours per brain if performed properly. After its development, this technique paved the way for researchers in the field of neurobiology to explore neuroanatomical connections in a murine model. While attempting this procedure, it's important to remember to keep the sections in ammonium hydroxide solution for only 19 to 21 minutes as to not overstain the neurons.After watching this video, you should have a good understanding of how to properly stain, section and rinse brain tissue. Don't forget that working with the mercuric chloride-based solution, ammonium hydroxide solution and xylene can be extremely hazardous, so take precautions and wear lab gloves and work in a fume hood when performing this procedure.

assessment-hippocampal-dendritic-complexity-aged-mice-using-golgi-cox

Research

JoVE Journal

Neuroscience

Assessment of Motor Balance and Coordination in Mice using the Balance Beam

Brain injury, genetic manipulations, and pharmacological treatments can result in alterations of motor skills in mice. Fine motor coordination and balance can be assessed by the beam walking assay. The goal of this test is for the mouse to stay upright and walk across an elevated narrow beam to a safe platform. This test takes place over 3 consecutive days: 2 days of training and 1 day of testing. Performance on the beam is quantified by measuring the time it takes for the mouse to traverse the beam and the number of paw slips that occur in the process. Here we report the protocol used in our laboratory, and representative results from a cohort of C57BL/6 mice. This task is particularly useful for detecting subtle deficits in motor skills and balance that may not be detected by other motor tests, such as the Rotarod.

Deficits in fine motor coordination can be assessed with the balance beam test. Performance on the beam is quantified by the speed at which the beam is traversed and the number of times the mouse slips on the beam.

Brain injury, genetic manipulations, and pharmacological treatments can result in alterations of motor skills in mice.  Fine motor coordination and ...

Fluorescence Recovery After Photobleaching (FRAP) of Fluorescence Tagged Proteins in Dendritic Spines of Cultured Hippocampal Neurons

FRAP has been used to quantify the mobility of GFP-tagged proteins. Using a strong excitation laser, the fluorescence of a GFP-tagged protein is bleached in the region of interest. The fluorescence of the region recovers when the unbleached GFP-tagged protein from outside of the region diffuses into the region of interest. The mobility of the protein is then analyzed by measuring the fluorescence recovery rate. This technique could be used to characterize protein mobility and turnover rate.
In this study, we express the (enhanced green fluorescent protein) EGFP vector in cultured hippocampal neurons. Using the Zeiss 710 confocal microscope, we photobleach the fluorescence signal of the GFP protein in a single spine, and then take time lapse images to record the fluorescence recovery after photobleaching. Finally, we estimate the percentage of mobile and immobile fractions of the GFP in spines, by analyzing the imaging data using ImageJ and Graphpad softwares.
This FRAP protocol shows how to perform a basic FRAP experiment as well as how to analyze the data.

Fluorescence Recovery After Photobleaching FRAP of Fluorescence Tagged Proteins in Dendritic Spines of Cultured Hippocampal Neurons

FRAP has been used to quantify the mobility of Green Fluorescence Protein (GFP)-tagged proteins in cultured cells. We examined the mobile/immobile fractions of the GFP by analyzing the fluorescence recovery percentage after photobleaching. In this study, FRAP was performed at spines of hippocampal neurons.

FRAP has been used to quantify the mobility of GFP-tagged proteins. Using a strong excitation laser, the fluorescence of a GFP-tagged protein is bleached ...

Assaying DNA Damage in Hippocampal Neurons Using the Comet Assay

A number of drugs target the DNA repair pathways and induce cell kill by creating DNA damage. Thus, processes to directly measure DNA damage have been extensively evaluated. Traditional methods are time consuming, expensive, resource intensive and require replicating cells. In contrast, the comet assay, a single cell gel electrophoresis assay, is a faster, non-invasive, inexpensive, direct and sensitive measure of DNA damage and repair. All forms of DNA damage as well as DNA repair can be visualized at the single cell level using this powerful technique.
	The principle underlying the comet assay is that intact DNA is highly ordered whereas DNA damage disrupts this organization. The damaged DNA seeps into the agarose matrix and when subjected to an electric field, the negatively charged DNA migrates towards the cathode which is positively charged. The large undamaged DNA strands are not able to migrate far from the nucleus. DNA damage creates smaller DNA fragments which travel farther than the intact DNA. Comet Assay, an image analysis software, measures and compares the overall fluorescent intensity of the DNA in the nucleus with DNA that has migrated out of the nucleus. Fluorescent signal from the migrated DNA is proportional to DNA damage. Longer brighter DNA tail signifies increased DNA damage. Some of the parameters that are measured are tail moment which is a measure of both the amount of DNA and distribution of DNA in the tail, tail length and percentage of DNA in the tail. This assay allows to measure DNA repair as well since resolution of DNA damage signifies repair has taken place. The limit of sensitivity is approximately 50 strand breaks per diploid mammalian cell 1,2. Cells treated with any DNA damaging agents, such as etoposide, may be used as a positive control. Thus the comet assay is a quick and effective procedure to measure DNA damage.

The comet assay is an efficient way of detecting single- and double-strand breaks, including alkali-labile sites and DNA-DNA/DNA-protein cross-links on the DNA in all cells including hippocampal neurons. The method takes advantage of the differential migration of DNA in an electric field due to differences in amount of DNA damage.

A number of drugs target the DNA repair pathways and induce cell kill by creating DNA damage. Thus, processes to directly measure DNA damage have been ...

Optogenetic Perturbation of Neural Activity with Laser Illumination in Semi-intact Drosophila Larvae in Motion

Drosophila larval locomotion is a splendid model system in developmental and physiological neuroscience, by virtue of the genetic accessibility of the underlying neuronal components in the circuits1-6. Application of optogenetics7,8 in the larval neural circuit allows us to manipulate neuronal activity in spatially and temporally patterned ways9-13. Typically, specimens are broadly illuminated with a mercury lamp or LED, so specificity of the target neurons is controlled by binary gene expression systems such as the Gal4-UAS system14,15. In this work, to improve the spatial resolution to "sub-genetic resolution", we locally illuminated a subset of neurons in the ventral nerve cord using lasers implemented in a conventional confocal microscope. While monitoring the motion of the body wall of the semi-intact larvae, we interactively activated or inhibited neural activity with channelrhodopsin16,17 or halorhodopsin18-20, respectively. By spatially and temporally restricted illumination of the neural tissue, we can manipulate the activity of specific neurons in the circuit at a specific phase of behavior. This method is useful for studying the relationship between the activities of a local neural assembly in the ventral nerve cord and the spatiotemporal pattern of motor output.

Optogenetic Perturbation of Neural Activity with Laser Illumination in Semi-intact Drosophila Larvae in Motion

Here we describe a protocol for optogenetic manipulation of motoneuronal activity while monitoring changes in motor output (muscle contraction) in semi-intact Drosophila larvae using lasers within a conventional confocal microscope. This technique enables researchers to achieve local perturbation of neural activity in a few neuromeres to elucidate the dynamics of motor circuits.

Drosophila larval locomotion is a splendid model system in developmental and physiological neuroscience, by virtue of the genetic accessibility of the ...

Visualizing the Effects of a Positive Early Experience, Tactile Stimulation, on Dendritic Morphology and Synaptic Connectivity with Golgi-Cox Staining

To generate longer-term changes in behavior, experiences must be producing stable changes in neuronal morphology and synaptic connectivity. Tactile stimulation is a positive early experience that mimics maternal licking and grooming in the rat. Exposing rat pups to this positive experience can be completed easily and cost-effectively by using highly accessible materials such as a household duster. Using a cross-litter design, pups are either stroked or left undisturbed, for 15 min, three times per day throughout the perinatal period. To measure the neuroplastic changes related to this positive early experience, Golgi-Cox staining of brain tissue is utilized. Owing to the fact that Golgi-Cox impregnation stains a discrete number of neurons rather than all of the cells, staining of the rodent brain with Golgi-Cox solution permits the visualization of entire neuronal elements, including the cell body, dendrites, axons, and dendritic spines. The staining procedure is carried out over several days and requires that the researcher pay close attention to detail. However, once staining is completed, the entire brain has been impregnated and can be preserved indefinitely for ongoing analysis. Therefore, Golgi-Cox staining is a valuable resource for studying experience-dependent plasticity.

This paper describes the procedures for tactile stimulation of rat pups and subsequent Golgi-Cox staining of neuronal morphology. Tactile stimulation is a positive experience that is administered in the perinatal period by stroking pups with a household duster. Golgi-cox staining is a reliable procedure permitting the visualization of entire neurons.

To generate longer-term changes in behavior, experiences must be producing stable changes in neuronal morphology and synaptic connectivity. Tactile ...

Fast Micro-iontophoresis of Glutamate and GABA: A Useful Tool to Investigate Synaptic Integration

One of the fundamental interests in neuroscience is to understand the integration of excitatory and inhibitory inputs along the very complex structure of the dendritic tree, which eventually leads to neuronal output of action potentials at the axon. The influence of diverse spatial and temporal parameters of specific synaptic input on neuronal output is currently under investigation, e.g. the distance-dependent attenuation of dendritic inputs, the location-dependent interaction of spatially segregated inputs, the influence of GABAergig inhibition on excitatory integration, linear and non-linear integration modes, and many more.
With fast micro-iontophoresis of glutamate and GABA it is possible to precisely investigate the spatial and temporal integration of glutamatergic excitation and GABAergic inhibition. Critical technical requirements are either a triggered fluorescent lamp, light-emitting diode (LED), or a two-photon scanning microscope to visualize dendritic branches without introducing significant photo-damage of the tissue. Furthermore, it is very important to have a micro-iontophoresis amplifier that allows for fast capacitance compensation of high resistance pipettes. Another crucial point is that no transmitter is involuntarily released by the pipette during the experiment.
Once established, this technique will give reliable and reproducible signals with a high neurotransmitter and location specificity. Compared to glutamate and GABA uncaging, fast iontophoresis allows using both transmitters at the same time but at very distant locations without limitation to the field of view. There are also advantages compared to focal electrical stimulation of axons: with micro-iontophoresis the location of the input site is definitely known and it is sure that only the neurotransmitter of interest is released. However it has to be considered that with micro-iontophoresis only the postsynapse is activated and presynaptic aspects of neurotransmitter release are not resolved. In this article we demonstrate how to set up micro-iontophoresis in brain slice experiments.

In this article we introduce fast micro-iontophoresis of neurotransmitters as a technique to investigate integration of postsynaptic signals with high spatial and temporal precision.

One of the fundamental interests in neuroscience is to understand the integration of excitatory and inhibitory inputs along the very complex structure of ...

Imaging Dendritic Spines of Rat Primary Hippocampal Neurons using Structured Illumination Microscopy

Dendritic spines are protrusions emerging from the dendrite of a neuron and represent the primary postsynaptic targets of excitatory inputs in the brain. Technological advances have identified these structures as key elements in neuron connectivity and synaptic plasticity. The quantitative analysis of spine morphology using light microscopy remains an essential problem due to technical limitations associated with light's intrinsic refraction limit. Dendritic spines can be readily identified by confocal laser-scanning fluorescence microscopy. However, measuring subtle changes in the shape and size of spines is difficult because spine dimensions other than length are usually smaller than conventional optical resolution fixed by light microscopy's theoretical resolution limit of 200 nm.
Several recently developed super resolution techniques have been used to image cellular structures smaller than the 200 nm, including dendritic spines. These techniques are based on classical far-field operations and therefore allow the use of existing sample preparation methods and to image beyond the surface of a specimen. Described here is a working protocol to apply super resolution structured illumination microscopy (SIM) to the imaging of dendritic spines in primary hippocampal neuron cultures. Possible applications of SIM overlap with those of confocal microscopy. However, the two techniques present different applicability. SIM offers higher effective lateral resolution, while confocal microscopy, due to the usage of a physical pinhole, achieves resolution improvement at the expense of removal of out of focus light. In this protocol, primary neurons are cultured on glass coverslips using a standard protocol, transfected with DNA plasmids encoding fluorescent proteins and imaged using SIM. The whole protocol described herein takes approximately 2 weeks, because dendritic spines are imaged after 16-17 days in vitro, when dendritic development is optimal. After completion of the protocol, dendritic spines can be reconstructed in 3D from series of SIM image stacks using specialized software.

This article describes a working protocol to image dendritic spines from hippocampal neurons in vitro using Structured Illumination Microscopy (SIM). Super-resolution microscopy using SIM provides image resolution significantly beyond the light diffraction limit in all three spatial dimensions, allowing the imaging of individual dendritic spines with improved detail.

Dendritic spines are protrusions emerging from the dendrite of a neuron and represent the primary postsynaptic targets of excitatory inputs in the brain. ...

Assessment of Dendritic Arborization in the Dentate Gyrus of the Hippocampal Region in Mice

Dendritic arborization has been shown to be a reliable marker for examination of structural and functional integrity of neurons. Indeed, the complexity and extent of dendritic arborization correlates well with the synaptic plasticity in these cells. A reliable method for assessment of dendritic arborization is needed to characterize the deleterious effects of neurological disorders on these structures and to determine the effects of therapeutic interventions. However, quantification of these structures has proven to be a formidable task given their complex and dynamic nature. Fortunately, sophisticated imaging techniques can be paired with conventional staining methods to assess the state of dendritic arborization, providing a more reliable and expeditious means of assessment. Below is an example of how these imaging techniques were paired with staining methods to characterize the dendritic arborization in wild type mice. These complementary imaging methods can be used to qualitatively and quantitatively assess dendritic arborization that span a rather wide area within the hippocampal region.

We describe two methods for visualization and quantification of dendritic arborization in the hippocampus of mouse models: real-time and extended depth of field imaging. While the former method allows sophisticated topographical tracing and quantification of the extent of branching, the latter allows speedy visualization of the dendritic tree.

Dendritic arborization has been shown to be a reliable marker for examination of structural and functional integrity of neurons. Indeed, the complexity ...

Fluorescence and Bioluminescence Imaging of Subcellular Ca2+ in Aged Hippocampal Neurons

Susceptibility to neuron cell death associated to neurodegeneration and ischemia are exceedingly increased in the aged brain but mechanisms responsible are badly known. Excitotoxicity, a process believed to contribute to neuron damage induced by both insults, is mediated by activation of glutamate receptors that promotes Ca2+ influx and mitochondrial Ca2+ overload. A substantial change in intracellular Ca2+ homeostasis or remodeling of intracellular Ca2+ homeostasis may favor neuron damage in old neurons. For investigating Ca2+ remodeling in aging we have used live cell imaging in long-term cultures of rat hippocampal neurons that resemble in some aspects aged neurons in vivo. For this end, hippocampal cells are, in first place, freshly dispersed from new born rat hippocampi and plated on poli-D-lysine coated, glass coverslips. Then cultures are kept in controlled media for several days or several weeks for investigating young and old neurons, respectively. Second, cultured neurons are loaded with fura2 and subjected to measurements of cytosolic Ca2+ concentration using digital fluorescence ratio imaging. Third, cultured neurons are transfected with plasmids expressing a tandem of low-affinity aequorin and GFP targeted to mitochondria. After 24 hr, aequorin inside cells is reconstituted with coelenterazine and neurons are subjected to bioluminescence imaging for monitoring of mitochondrial Ca2+ concentration. This three-step procedure allows the monitoring of cytosolic and mitochondrial Ca2+ responses to relevant stimuli as for example the glutamate receptor agonist NMDA and compare whether these and other responses are influenced by aging. This procedure may yield new insights as to how aging influence cytosolic and mitochondrial Ca2+ responses to selected stimuli as well as the testing of selected drugs aimed at preventing neuron cell death in age-related diseases.

Fluorescence and Bioluminescence Imaging of Subcellular Ca2+ in Aged Hippocampal Neurons

Intracellular Ca2+ remodeling in aging may contribute to excitotoxicity and neuron damage, processes mediated by Ca2+ overload. We aimed at investigating Ca2+ remodeling in the aging brain using fluorescence and bioluminescence imaging of cytosolic and mitochondrial Ca2+ in long-term cultures of rat hippocampal neurons, a model of neuronal aging.

Susceptibility to neuron cell death associated to neurodegeneration and ischemia are exceedingly increased in the aged brain but mechanisms responsible ...

Imaging Neurons within Thick Brain Sections Using the Golgi-Cox Method

The Golgi-Cox method of neuron staining has been employed for more than two hundred years to advance our understanding of neuron morphology within histological brain samples. While it is preferable from a practical perspective to prepare brain sections at the greatest thickness possible, in order to increase the probability of identifying stained neurons that are fully contained within single sections, this approach is limited from a technical perspective by the working distance of high-magnification microscope objectives. We report here a protocol to stain neurons using the Golgi-Cox method in mouse brain sections that are cut at 500 &#956;m thickness, and to visualize neurons throughout the depth of these sections using an upright microscope fitted with a high-resolution 30X 1.05 N.A. silicone oil-immersion objective that has an 800 &#956;m working distance. We also report two useful variants of this protocol that may be employed to counterstain the surface of mounted brain sections with the cresyl violet Nissl stain, or to freeze whole brains for long-term storage prior to sectioning and final processing. The main protocol and its two variants produce stained thick brain sections, throughout which full neuron dendritic&#160;trees and dendrite spines may be reliably visualized and quantified.

We present a protocol for using the Golgi-Cox staining method in thick brain sections, in order to visualize neurons with long dendritic&#160;trees contained within single tissue samples. Two variants of this protocol are also presented that involve cresyl violet counterstaining, and the freezing of unprocessed brains for long-term storage.