Combined vascular-bronchoalveolar casting using formalin-fixed canine lungs and a low viscosity silicone rubber.

Background: Previous work using unfixed or fixed tissues has shown that casts can be made that demonstrate the three-dimensional structure of tissues such as the bronchoalveolar tree or the vasculature. In this report, a new method for creating a vascular-bronchoalveolar cast is described.

Method: Canine lungs were taken from storage in formalin. Silastic 734 RTV (room temperature vulcanizing) with added red or blue pigments was injected into the pulmonary arteries and veins, respectively, using compressed air. This was followed by filling the airway with clear (translucent) Silastic 734 RTV. The lung tissue was then corroded with potassium hydroxide.

Results: Vascular-bronchoalveolar casts were recovered giving fine detail as shown using stereo light microscopy or scanning electron microscopy.

Conclusions: This method may be useful for not only microvascular anatomy studies of lungs, but also for studying the microvasculature of other normal and diseased tissues.