Reflected light confocal microscopy can reveal details not visible using standard transmitted light techniques. Dr. Paddock utilized this technique to capture stress fibers in Swiss mouse embryo (3T3) fibroblast cells grown in monolayer cell culture.

Stress Fibers in 3T3 Cells Specimen: 3T3 Cells Technique: Confocal Reflected Light

The 3T3 tissue culture cell line is composed of fibroblasts from an albino Swiss mouse embryo. Fibroblasts are cells that develop into connective tissue and display a distinct morphology when grown in culture. This well-known cell line was established in 1962, and throughout the 1960's and 1970's, the cell line was widely used in oncogenic virus studies. Now these contact-inhibited fibroblasts are used more extensively as feeder cells for other rodent or human cells.

3T3 has also been heavily employed in the study of endogenous retroviruses in rodents. Endogenous retroviruses are responsible for rapid adaptation of organisms by assisting with importation and incorporation of “alien” genetic material by the host. The organisms are heavily utilized by evolutionary biologists and phylogeneticists to explain speciation and the relations of species. They are also becoming increasing more important to genetic engineers who are experimenting with placing foreign genetic matter into new organisms to achieve desired traits.