ORO Flashcards
Oil red O
classification
target tissue component
mechanism of staining
positive controls
Classification: Connective Tissue stain
Target tissue component: Lipids
Mechanism of Staining: Selective solubility
Positive controls: any tissue containing fat
What are some characteristics of lipids
hydrophobic
-lipids dont have reactive groups and dont carry a charge
What are the criteria of successful lipid staining
use the dye in the solvent where it is not readily soluble
apply to tissues containing lipid
dye is more soluble in lipid that is in the tissue
dye solvent must not dissolve out any lipid
What is step 1
primary stain
Oil Red O—demonstrates lipids
Progressive stain
What is oil red O
Non-polar (i.e., unable to dissolve in water)
Not a true dye (does not contain an auxochrome); called a lysochrome
Solubility vs. Selective Solubility
Solubility-The degree to which a solute is able to dissolve in a solvent
Selective Solubility-A solute that is more soluble in one solvent than another
Solubility of Polar vs. Non-Polar Molecules in Water
Polar -carries a charge and is able to form bonds with water
non polar-Does not carry a charge and is unable to form bonds with water
Changing the Degree of Solubility
-oil red is dissolved in 100% isopropanol - STOCK
-some of the stock is diluted in water (60% isopro) making the dye soluble in water but not completely
-since the dye likes being in a substance where it is completely soluble it will move from the working solution into the lipid because it is more soluble in the lipid than in the solvent of the working solution
What is step 2
STEP 2: Rinse
60% isopropanol
Removes background staining
What is step 3
Counterstain
-Hematoxylin- Stains nuclei and other tissue
- used progressively or regressively
-If used regressively, aqueous hydrochloric acid must be used
What are the results of ORO
Fat – Red
Nuclei - Blue
dont forget it needs a frozen section
