Staining sections of water-miscible resins. 2. Effects of staining-reagent lipophilicity on the staining of glycol-methacrylate-embedded tissues.
Glycol methacrylate (GMA) sections of animal tissues were stained with a group of twenty-seven reagents of very varied chemical characteristics. The artefactual background staining of the resin was found to be dependent on the hydrophilic/lipophilic character of the staining reagent, as estimated from the logarithm of its octanol-water partition coefficient (log P). Intense background staining occurred with lipophilic stains, whose log P greater than 2. In keeping with this, use of GMA semi-permeable membranes for enzyme histochemistry failed to give staining when using a lipophilic substrate, probably because the substrate was trapped in the membrane. An analysis of other routine histochemical stains--in terms of the probable occurrence of high resin background staining and low tissue sensitivity--is made. A numerical guide is provided to help avoid artefacts resulting from hydrophobic and size effects. Note: small, hydrophilic reagents (log P less than 0; molecular weight less than 550 Da) are least likely to show either type of artefact. Conversely, reagents which are lipophilic, or/and of intermediate size (log P greater than 2; 550 less than ionic weight less than 1000 Da), give strong background staining.
Horobin
R W
RW
Department of Biomedical Science, University, Sheffield, U.K.
Gerrits
P O
PO
Wright
D J
DJ
D000818:Animals; D050356:Lipid Metabolism; D008867:Microtomy; D011102:Polyhydroxyethyl Methacrylate; D051381:Rats; D013194:Staining and Labeling; D014867:Water / Q000378:metabolism
D014867:Water; D011102:Polyhydroxyethyl Methacrylate