Chapter 9: Nerve Flashcards
Cresyl Echt Violet 1 Purpose
Identification of neurons or demonstration of lost Nissl substance that indicates neuronal injury
Cresyl Echt Violet 1 Principle
Nissl substance is very basophilic due to RNA content, and therefore stains sharply with basic aniline dyes
Adjusting pH can show both Nissl and nuclei or only Nissl
Cresyl Echt Violet 1 Preferred Fixative
10% NBF
Spinal cord control
Cresyl Echt Violet 1 Basic Procedure
- Deparaffinize, hydrate
- Stain in cresyl echt violet (ripen for 24-48 hours and filter before use)
- Rinse in distilled water
- Place sections in 95% alcohol
- Transfer sections to absolute alcohol
- Place in xylene
- Place in balsam-xylene mixture
- Differentiate in absolute alcohol, check sections microscopically
- Several changes of xylene
- repeat 7-9 multiple times until differentiation is complete; background should be colorless and blue to purple nuclei and Nissl
- Coverslip
Cresyl Echt Violet 1 Results
Nissl substance and nuclei: blue to purple
background: colorless
Cresyl Echt Violet 1 Technical notes
Differentiation should be repeated until the background is colorless. This usually requires several repetitions
The alcohol following the balsam-xylene mixture will become cloudy and should be changed frequently
Cresyl Echt Violet 2 Purpose
Identify neurons or loss of Nissl substance (chromatolysis)
Cresyl Echt Violet 2 Principle
Same as method one, but the cresyl echt violet is at an acidic pH which enhances contrast between the background and Nissl or nuclei
Cresyl Echt Violet 2 Preferred Fixative
10% NBF
Cresyl Echt Violet 2 Basic Procedure
- Deparaffinize, hydrate
- stain in acidic cresyl echt violet (includes alcohol and acetic acid)
- Dehydrate, clear, coverslip
Cresyl Echt Violet 2 Results
Nissl substance and nuclei: blue-purple
Background: colorless
Cresyl Echt Violet 2 Technical notes
Macroscopically the slides will appear unstained
Cresyl echt violet from Luxol fast blue stain may also be used to identify Nissl substance
Bodian Method Purpose
Stain nerve fibers
Bodian Method Principle
- Protargol (brand name silver proteinate) impregnates tissue
- Copper is added to impregnating solution to “destain” connective tissue to improve differentiation
- Hydroquinone reduces the deposited silver salts into visible metallic silver
- Gold chloride is the toner (oxalic acid can be used to reduce the gold and intensify the stain)
- Sodium thiosulfate removes unreduced silver
Bodian Method Preferred Fixative
10% NBF
Control: peripheral nerve or cerebral cortex to avoid cross-section
Bodian Method Basic Procedure
- Deparaffinize, hydrate
- Add clean copper shot to Protargol at 37C for 48 hours
- Rinse in distilled water
- place in reducing solution
- Rinse in water
- Tone in gold chloride
- rinse in water
- Develop in Oxalic Acid, checking microscopically until the background is grey and the nerve fibers appear clearly stained. Don’t treat too long or it will ruin the silver
- Rinse in water
- Treat with sodium thiosulfate to remove unreduced silver
- Rinse in distilled water
- Counterstain, if desired, with aniline blue
- Dehydrate, clear, coverslip
Bodian Method Results
Nerve fibers and nuclei: black
Background: light grey or blue (if counterstained)
Bodian Method Technical notes
Copper shot is cleaned with aqua regia (HCl +Nitric Acid). After use it should be gradually poured into a very large volume of water and then discarded in the sink. Do not pour directly into sink, do not add water to the acid.
Protargol should be left undisturbed until it is completely dissolved
use chemically clean glassware and non-metallic forceps
Don’t overcounterstain with Aniline blue
You can also use nuclear fast red as a counterstain
Holmes Silver Nitrate Method Purpose
Demonstrate nerve fibers and neurofibrils
Holmes Silver Nitrate Method Principle
Bodian doesn’t work well because the Protargol solution never reaches necessary alkalinity for proper impregnation. Holmes developed a buffered impregnation solution
This is an argyrophil silver method that requires chemical reduction
Gold chloride toner, Oxalic acid reducer, and sodium thiosulfate are the same as in Bodian
Holmes Silver Nitrate Method Preferred Fixative
10% NBF
Control: peripheral nerve or cerebral cortex to avoid cross-section
10-15uM paraffin
Holmes Silver Nitrate Method Basic Procedure
- Deparaffinize, hydrate
- Place in 20% silver nitrate in the dark
- Prepare impregnating solution (Boric acid, Borax, water, silver nitrate, pyridine)
- Wash slides in distilled water
- Place slides in impregnating solution overnight at 37C
- Remove slides, shake of excess fluid, and place in reducer (hydroquinone, sodium sulfite, water)
- wash in running water
- Rinse in distilled water
- Tone in gold chloride (can be re-used until brown precipitate forms or the solution becomes cloudy)
- Rinse in distilled water
- Place slides in oxalic acid, when the axons are thoroughly blue-black, stop the process
- Rinse in distilled water
- place in sodium thiosulfate
- wash in tap water. Counterstain if desired
- Dehydrate, clear, coverslip
Holmes Silver Nitrate Method Results
Axons and nerve fibers: black
Neurofibrils: black
Holmes Silver Nitrate Method Technical notes
Pyridine is toxic by ingestion, inhalation, and skin absorption. Use under a fume hood with gloves and goggles
Bielschowsky-PAS Purpose
To demonstrate nerve fibers, neurofibrillary tangles, and senile plaques in Alzheimer disease
Bielschowsky-PAS Principle
- impregnate with ammoniacal silver which deposits on neurofibrils and axons
- silver is reduced to metallic silver by formaldehyde in the developer
- Gold chloride tones the tissue and removes yellow
- sodium thiosulfate removes unreduced silver background
- schiff reaction (PAS) stains basement membranes and amyloid in the plaques
Bielschowsky-PAS Preferred Fixative
10% NBF
Control: CNS tissue containing plaques and tangles
Bielschowsky-PAS Basic Procedure
- Prepare ammoniacal silver solution
- Deparaffinize, hydrate
- Place in silver nitrate solution in the dark at room temp
- Wash with distilled water
- Place in ammoniacal silver solution
- Wash in ammonia water
- While slides are in ammonia water, add 2 drops of developer to the ammoniacal silver solution from step 5
- place slides in ammoniacal/developer solution. The tissue should turn brown in about 3 minutes
- Wash well in ammonia water, then distilled water
- Tone in gold chloride until grey appears
- Wash in ammonia water, then rinse in distilled water
- Place in sodium thiosulfate
- Wash in running tap water
- Rinse well in distilled water
- Place sections in 1% periodic acid
- Rinse in distilled water
- Place in schiff reagent
- Wash in tap water
- Dehydrate, clear, coverslip
Bielschowsky-PAS Results
Neurofibrillary tangles: dark black
Peripheral neurites and plaques: dark black
Axons: black
Amyloid (plaque cores and vasculature): magenta
Lipofuchsin: magenta
Bielschowsky-PAS Microwave Purpose
Demonstrate nerve fibers, tangles, and plaques in Alzheimer’s
Bielschowsky-PAS Microwave Principle
Sections are not toned with gold chloride so yellow background remains
Bielschowsky-PAS Microwave Preferred Fixative
10% NBF
Control: CNS with plaques and tangles
Bielschowsky-PAS Microwave Basic Procedure
- Deparaffinize, hydrate
- Place slides in 1% Silver Nitrate, dip several times and incubate in warm solution for 15 minutes
- Place slides in distilled water
- 1% silver nitrate from step 2 + 28% ammonium drops until precipitate clears, then 5% silver nitrate drops until solution becomes slightly cloudy
- microwave slides in the solution, dip slides and incubate in warm solution
- Place slides in 1% ammonium hydroxide
- add 3 drops developer to ammoniacal silver from step 5, place slides in solution until tissue turns brown
- Place slides in 1% ammonium hydroxide
- Rinse in distilled water
- Wipe silver mirror off both sides of slide without disturbing the tissue
- place slides in 2% sodium thiosulfate
- Rinse slides in distilled water
- Dehydrate, clear, coverslip
Bielschowsky-PAS Microwave Results
Axons: brown to black Cytoplasmic neurofibrils: brown to black Tangles and plaques: dark brown or black Neuromelanin: black Lipofuchsin: brown or black
Bielschowsky-PAS Microwave Technical notes
Use chemically cleaned glassware, non-metallic forceps
Uses much less silver nitrate than traditional Bielschowsky and stains tangles and plaques better
Sevier-Munger Modification of Bielschowsky Purpose
Demonstrate nerve fibers, tangles, and plaques for Alzheimer’s
Sevier-Munger Principle
Ammoniacal silver impregnation
Reduced by formaldehyde developer
No toning with gold chloride so yellow background remains
Sodium Thiosulfate removes unreduced silver
Sevier-Munger Preferred Fixative
10% NBF
Control: CNS with tangles and plaques
6-8uM sections
Sevier-Munger Basic Procedure
- Deparaffinize, hydrate
- Preheat 20% silver nitrate, then add slides to warm silver solution and incubate in the oven
- Rinse one slide at a time in distilled water and place in a clean, dry staining jar
- add 10 drops formalin, while agitating, to working ammoniacal silver solution, pour over slides and develop until golden brown. Check microscopically, do not wash while checking, keep in motion while developing to avoid precipitation
- Rinse slides well in tap water
- Place in sodium thiosulfate
- Wash well in tap water
- Dehydrate, clear, coverslip
Sevier-Munger Results
Nerve endings and neurofibrils: black
Tangles, peripheral neurites, and plaques: black
Sevier-Munger Technical notes
Very reliable and reproduce-able technique
Concentration of ammonium hydroxide and formalin are critical
leave a few particles of silver, do not add extra ammonia
This is an argyrophil stain that is also useful fro demonstrating the granules of some carcinoid tumor cells
Thioflavin S (modified) Purpose
Demonstrates presence of tangles, plaques, threads in addition to parenchymal and amyloid deposition in Alzheimer’s disease
Thioflavin S (modified) Principle
Fluorescent visualization of amyloid
Pretreatment with potassium permanganate, and bleaching with potassium metabisulfate and oxalic acid
Treatment with sodium hydroxide and hydrogen peroxide, which remove lipid autofluorescence for better definition of pathological lesions
Visualization is better than routine Thioflavin S ans is not affected by prolonged fixation
More sensitive than silver methods
Faster and cheaper than silver
Thioflavin S (modified) Preferred Fixative
10-20% NBF
Control: CNS with plaques and tangles
6um sections air dried overnight, then 10 minutes in 60C oven
Thioflavin S (modified) Basic Procedure
- Deparaffinize, hydrate
- Rinse and old in distilled water
- cover tissue with 0.25% potassium permanganate
- wash slides in running tap water
- treat slides with 1% potassium bisulfate
- wash in running tap water
- place in sodium hydroxide-peroxide
- wash in running tap water and then filtered water
- place slides in 0.25% acetic acid
- wash slides in running tap water
- place slides in 50% alcohol
- place in Thioflavin S
- rinse slides in 50% alcohol with agitation
- Rinse in 95% alcohol
- completely dehydrate in absolute alcohol and clear in xylene. Mount with non-fluorescent mounting medium
- View slides on a fluorescent filter set that incorporates a blue-violet excitation filter
Thioflavin S (modified) Results
tangles, neurites, threads, plaque amyloid, and cerebrovascular amyloid: bright green
Diffuse plaques and extracellular plaques: paler yellow green
PSP tangles and Pick bodies: not well demonstrated
Thioflavin S (modified) Technical notes
Float tissue on pre-heated DI water bath
Mount sections with cytoseal 60
Staining is stable for several months at room temp
PTAH Purpose
Demonstration of glial fibers (also used to demonstrate muscle striations)
PTAH Principle
High ratio of PTA to hematein 20:1 so that tungsten binds all available hematein to form a blue lake which stains glial fibers, nuclei, and myelin. Red brown or salmon color of neurons is due to the PTA alone. Overuse of alcohol will fade the red-brown
PTAH Preferred Fixative
10% NBF
6-8uM sections
Control: Cerebral cortex (not spinal cord)
PTAH Basic Procedure
- Deparaffinize, hydrate
- Mordant the sections overnight at room temp in Zenker solution containing acetic acid
- Wash sections in running water
- Place in Lugol Iodine. Do not use sodium thiosulfate because it may impair subsequent staining
- Decolorize the sections in 95% alcohol for 1 hour
- Rinse rapidly in distilled water
- Place in 1% potassium permanganate
- Wash in running tap water
- Decolorize the sections in 5% oxalic acid
- Wash in running tap water
- Stain in PTAH overnight
- Dehydrate, clear, coverslip
PTAH Results
Glial fibers: blue
Nuclei: blue
Neurons: salmon
Myelin: blue
PTAH Technical notes
Replaced by immunohistochemical methods
Don’t over rinse in EtOH
Don’t use sodium thiosulfate or stain won’t work
Holzer Method Purpose
To demonstrate glial fibers and areas of gliosis (glial damage)
Holzer Method Principle
Glial fibers are stained with crystal violet and are resistant to decolorization with an alkaline aniline-chloroform mixture
Holzer Method Preferred Fixative
10% NBF
6-8uM sections
Control: Cerebral cortex, not spinal cord
Holzer Method Basic Procedure
- Deparaffinize, hydrate
- place in PMA-alcohol
- Drain off excess fluid, place slides in a staining rack and cover the sections with absolute alcohol-chloroform mixture. The tissue should become translucent
- While sections are still wet, cover them with the crystal violet stain
- Replace the stain with 10% potassium bromide
- Blot the sections dry and then allow them to air dry
- Differentiate in aniline-oil+chloroform+ammonium hydroxide differentiating solution
- Wash in several changes of xylene. Repeat steps 7 and 8 until the background is very pale or colorless
- Mount with synthetic resin
Holzer Method Results
Glial fibers: blue
Background: very pale blue to colorless
Holzer Method Technical notes
Crystal Violet precipitate may be removed with straight aniline oil
Aniline oil and chloroform are both very hazardous; use in a chemical fume hood
The aniline oil-chloroform-ammonium hydroxide differentiating solution resists decolorization
Cajal Method Purpose
Demonstrate astrocytes
Cajal Method Principle
Astrocytes are selectively stained with the Cajal gold sublimate method on frozen sections
Cajal Method Preferred Fixative
Formalin ammonium bromide for 2-25 days, rinse and place in formalin ammonium bromide for 2 days if previously fixed with 10% NBF
20-30uM Sections, free floating, no slides
Control: cerebral cortex, not spinal cord
Cajal Method Basic Procedure
- wash free floating frozen sections in several changes of distilled water
- Transfer the sections to the gold sublimate solution (gold chloride + mercuric chloride) and incubate in the dark for 4 hours, sections should turn purple
- Wash well in distilled water
- Treat with 5% sodium thiosulfate
- Wash in distilled water
- Carefully mount the sections on slides, blot and dehydrate
- Clear in xylene and mount with synthetic resin
Cajal Method Results
Astrocytes: black
Cajal Method Technical notes
Tissue sections better if washed in tap water for 30 minutes before freezing
chemicals must be pure; brown chloride is preferred over yellow gold chloride
Protoplasmic (grey matter) astrocytes lose stainability after prolonged fixation
Staining solution should not exceed 30C
mixture of mercuric chloride and gold chloride is essential for astrocyte demonstration
mercuric chloride is extremely toxic and an environmental hazard
Weil’s Purpose
Demonstration of myelin
Myelin degeneration, such as in syphilis
Weil’s Principle
Mordant-hematoxylin solutions attaches to the phospholipid component of the myelin sheath, which has an affinity for the cationic (+) lake
Regressive technique
1. Ferric ammonium sulfate: excess mordant differentiation removes most of the excess dye
2. Borax ferricyanide: oxidizer differentiation which removes any remaining non-specifically bound hematoxylin lake and forms a colorless oxidation product.
Only myelin sheath and red blood cells remain stained
Weil’s Preferred Fixative
10% NBF
10-15uM Sections
Control: Spinal cord or medulla
Weil’s Basic Procedure
- Deparaffinize, hydrate
- Transfer sections to staining solution for 30 minutes at 54-56C
- Wash in tap water
- Differentiate in 4% ferric ammonium sulfate until the gray matter can just be distinguished from the white matter and the stain is removed from the slides
- Wash in tap water
- Complete differentiation in the sodium borate-potassium ferricyanide solution. This should be checked until the grey and white matter are sharply defined
- Wash in tap water
- Treat sections in diluted ammonia water
- Wash in distilled water
- Dehydrate, clear, coverslip
Weil’s Results
Myelin sheath: blue to blue-black
Background: light tan
Weil’s Technical notes
Gray matter and demyelinated white matter should appear light brown and contrast sharply with blue-black myelinated white matter
Easy macroscopic differentiation
Naturally ripen for 6 months or chemically ripen with ferric ammonium sulfate
Luxol Fast Blue Purpose
Demonstrate myelin
Luxol Fast Blue Principle
Similar to alcian blue, but is alcohol rather than water soluble. Staining is accomplished through an acid-base reaction in which the base of the myelin lipoprotein swaps with the base of the dye
Luxol Fast Blue Preferred Fixative
10% NBF
10-15uM Sections
Control: spinal cord or medulla
Luxol Fast Blue Basic Procedure
- Deparaffinize, hydrate
- Place slides in LFB (Luxol Fast Blue) and incubate overnight at 56-58C
- Rinse in 95% alcohol to remove excess stain (LFB is alcohol soluble)
- Rinse in water
- Begin differentiating by immersing slides in lithium carbonate solution
- Continue differentiation in 70% alcohol until gray matter and white matter can be distinguished. Do not over differentiate
- Wash in distilled water
- Finish differentiation by rinsing briefly in lithium carbonate and then through several changes of 70% alcohol until the greenish blue of the white matter contrasts sharply with colorless grey matter
- Rinse in distilled water
- Dehydrate, clear, coverslip
Luxol Fast Blue Results
Myelin: blue to blue-green
Background: colorless
Luxol Fast Blue Technical notes
Gray matter and demylinated white matter should be almost colorless and contrast sharply with blue stained myelinated white matter
Quality of the stain (contrast) can be determined macroscopically
Differentiate until gray matter is almost colorless
LFB-Holmes silver nitrate Purpose
Demonstrate myellin and nerve fibers in the same section
LFB-Holmes silver nitrate Principle
LFB staining is accomplished through an acid-base reaction in which the base of the myelin lipoprotein swaps with the base of the dye
Holmes is an argyrophil silver method that requires chemical reduction
Gold chloride toner, Oxalic acid reducer, and sodium thiosulfate
LFB-Holmes silver nitrate Preferred Fixative
10% NBF
10-15uM Sections
Control: Cerebral cortex or longitudinal section of peripheral nerve
LFB-Holmes silver nitrate Basic Procedure
- Deparaffinize, hydrate
- 20% silver nitrate in the dark at room temp
- make impregnating solution (boric acid+borax+silver nitrate+pyradine)
- Take slides out of 20% silver nitrate and wash in distilled water
- 37C overnight incubation in impregnating solution
- shake off excess fluid, and place in reducer (hydroquinone+sodium sulfite)
- Wash in running water, then distilled water
- Tone in gold chloride. Solution may be reused until a brown precipitate forms or the solution becomes cloudy
- Rinse in distilled water
- Place in oxalic acid, stop when sections are blue-black
- Rinse in distilled water
- Place slides in sodium thiosulfate
- Wash in tap water
- place in 95% alcohol
- Stain in LFB overnight at 60C
- place in 95% alcohol
- Place in distilled water
- Place in lithium carbonate
- Differentiate in 70% alcohol
- Rinse in distilled water (repeat steps 18-20 until desired differentiation is achieved)
- Dehydrate, clear, coverslip
LFB-Holmes silver nitrate Results
Myelin: blue to green
Axons and nerve fibers: black
LFB-cresyl echt violet Purpose
Demonstrate both myelin and Nissl substance
LFB-cresyl echt violet Principle
LFB staining is accomplished through an acid-base reaction in which the base of the myelin lipoprotein swaps with the base of the dye
Cresyl echt violet uses a basic aniline dye to stain RNA blue, thus demonstrating the RNA in the rough endoplasmic reticulum which comprises the Nissl substance
LFB-cresyl echt violet Preferred Fixative
10% NBF
10-15uM sections
Control: spinal cord or medulla
LFB-cresyl echt violet Basic Procedure
- Deparaffinize, hydrate
- Place slides in LFB, incubate overnight in 56-58C
- rinse in 95% alcohol to remove excess stain
- Rinse in distilled water
- Begin differentiation by immersion in lithium carbonate
- Continue differentiation in 70% alcohol until grey and white matter can be distinguished
- Rinse in distilled water
- Finish differentiation by rinsing briefly in lithium carbonate and then through several changes of 70% alcohol until sharp contrast is achieved
- Rinse in distilled water
- Add acetic acid, filter, and preheat cresyl echt violet. Place slides in cresyl echt violet for 6 minutes, keep warm while staining.
- Differentiate in several changes of 95% alcohol
- Dehydrate, clear, coverslip
LFB-cresyl echt violet Results
Myelin: blue (from LFB)
Nissl substance: violet (from cresyl)
Nuclei: violet (from cresyl)
LFB-cresyl echt violet Technical notes
If you don’t add acetic acid to the CEV, you will get a diffuse violet background stain
Staining of Nissl will be reduced if you don’t heat the CEV prior to staining
CEV counterstain intensifies the myelin sheath stain
LFB-PAS-Hematoxylin Purpose
Demonstrate myelin sheath, basement membranes, senile plaques, fungi, and corpora amylacea
The various stains sharpen and complement each other
LFB-PAS-Hematoxylin Principle
LFB staining is accomplished through an acid-base reaction in which the base of the myelin lipoprotein swaps with the base of the dye
Periodic acid oxidizes reactive groups to form aldehydes (-CHO)
Basic fuschin + sulfurous acid = leucofuschin/Schiff’s reagent which binds to exposed aldehyde groups
Water washes away the sulfur resulting in the rose chromophore
LFB-PAS-Hematoxylin Preferred Fixative
10% NBF
10-15uM Sections
Control: Cerebral cortex or medulla
LFB-PAS-Hematoxylin Basic Procedure
- Deparaffinize, hydrate
- Incubate in LFB overnight at 56-58C
- Rinse in 95% alcohol to remove excess stain
- Rinse in distilled water
- Begin differentiation by placing in lithium carbonate
- Continue differentiation in 70% alcohol until grey and white matter become distinguished
- Wash in distilled water
- Finish differentiation by rinsing briefly in lithium carbonate and then through several changes of 70% alcohol until sharp contrast is achieved (repeat 7-8 as necessary)
- Rinse in distilled water
- Place in periodic acid (aldehyde formation)
- Place in distilled water
- Place in schiff solution
- Wash in tap water
- Stain with Harris hematoxylin
- Wash in tap water (if background is not clear dip once in acid-alcohol and wash, if nuclei are not dark blue to purple dip briefly in dilute ammonium hydroxide and wash)
- Dehydrate, clear, coverslip
LFB-PAS-Hematoxylin Results
Capillary basement membranes: Rose Fungi: Rose Corpora amylacea: Rose Senile plaques: Rose Myelin Sheath: Blue to blue-green Nuclei: purple
Two anatomic parts of the nervous system
CNS: brain and spinal cord
PNS: everything else
2 functional parts of the nervous system
Somatic: voluntary
Autonomic: involuntary
3 groups of nervous system stains based on stain target
Neuronal cell bodies and processes
Glial cells and processes
Myelin sheath
Neuron
Cellular unit of the nervous system, conduct information vial electrochemical impulses
What are the structural components of a neuron?
Cell body containing nucleus Dendrites Axon Myelin sheath Node of Ranvier
Characteristics of Nissl Substance
Basophilic: stains blue/black with hematoxylin, or basic aniline dyes like thionin and cresyl echt violet
Large aggregates of rough endoplasmic reticulum with RNA content being stained
Neuroglia
“Nerve glue” like a connective tissue for the CNS
Insulate neurons except at synapses
produce the myelin sheath
4 types of glial cells
Oligodendroglia/oligodendrocytes
Astrocytes
Microglia
Ependymal Cells
Oligodendroglia
Produce and maintain myelin sheath in the CNS
Astrocytes
Protoplasmic(gray) and fibrous(white)
help in scar formation after brain injury
support nerve fibers
Star shaped (stellate)
Microglia
fixed phagocytic cells found throughout the brain and spinal cord (immune response)
Ependymal Cells
Epithelium with a brush border that acts as the blood/brain barrier
Myelin
Fatty insulation around neurons
Stains with lipid stains
Deposited by oligodendrocytes on multiple neurons in the CNS
Deposited by Schwann cells on individual neurons in the PNS
Typically demonstrated with Luxol fast blue and iron hematoxylin