An alternative Alcian Blue dye variant for the evaluation of fetal cartilage.
BACKGROUND
The most comprehensive evaluation of vertebrate skeletal development involves the use of Alizarin Red S dye to stain ossified bone and various other dyes to stain cartilage. The dye used most widely to stain fetal cartilage in rodents and rabbits is Alcian Blue 8GX. However, the global supply of this specific dye has been exhausted. Several forms of the dye marketed as Alcian Blue 8GX are now available, although they are not synthesized via the original 8GX manufacturing process.


METHODS
One new Alcian Blue 8GX form and two Alcian Blue dye variants were evaluated in rats and rabbits using standard staining procedures. The staining quality of these dyes were evaluated relative to the original form of Alcian Blue 8GX based on cartilage uptake of the dye, clarity of the cartilaginous components, staining intensity of the dye, and overall readability of the specimens under stereomicroscopic evaluation.


RESULTS
Staining with the newer form of Alcian Blue 8GX resulted in poor staining quality. The Alcian Blue-Pyridine variant performed well, although staining intensity was less than optimal. The Alcian Blue-Tetrakis variant provided staining characteristics that were most similar to the original form of Alcian Blue 8GX.


CONCLUSIONS
Alcian Blue-Tetrakis was markedly better in its ability to stain fetal cartilage than the newer form of Alcian Blue 8GX.
Redfern
Brian G
BG
Developmental and Reproductive Toxicology, Safety Assessment, Merck Research Laboratories, West Point, Pennsylvania 19486, USA. brian_redfern@merck.com
David Wise
L
L
Spence
Stan
S
D000423:Alcian Blue / Q000031:analogs & derivatives*; D000818:Animals; D001842:Bone and Bones / Q000033:anatomy & histology / Q000196:embryology*; D002356:Cartilage / Q000033:anatomy & histology / Q000196:embryology*; D004396:Coloring Agents; D005260:Female; D005333:Fetus / Q000033:anatomy & histology*; D011247:Pregnancy; D011817:Rabbits; D051381:Rats; D013194:Staining and Labeling / Q000379:methods
C418049:Alcian blue pyridine variant; D004396:Coloring Agents; D000423:Alcian Blue