Use of tracheal organ cultures in toxicity testing.

Fragments of tracheal epithelium alone or in continuity with connective tissues, can be maintained in culture medium and used for short term or long term studies of toxicity of a variety of chemicals. Large numbers of uniform cultures are prepared with the aid of a slicing device or by application of simple method for dissecting sheets of epithelium free from underlying cartilage. The cultures may be placed in an exposure chamber-incubator mounted on a microscope stage and monitored continually for ciliostasis and exfoliation of cells. Morphology is further studied by fixation of selected specimens and preparation for light microscopy and electron microscopy. Synthetic functions are evaluated by autoradiographic measurement of incorporation of radioactive precursors into macromolecules and other dynamic features are indirectly assessed by histochemical and histoenzymatic methods. Short-term studies using these several techniques have shown that ciliostasis does not correlate with cell injury in all instances, and a long-term study has demonstrated dose dependence of a cytotoxic agent when duration of culture viability is measured. The method lends itself to a broad range of investigations in which dose, period of exposure, and role of cofactors must be independently and quantitatively assessed.