In situ cryofixation of lung tissue using the PS1000, a hand-held metal mirror cryofixation device

Abstract

We have previously reported methods to cryofix the extracellular lining layers of the large airways and trachea. We seek to study the extracellular lining layers of both airways and alveoli in situ because it is the interaction of these lining materials with inhaled particles that determines the subsequent responses of phagocytic cells to the particles. Cryopreservation of the lining fluids of lung parenchyma is difficult because of the complexity of distal lung structure, and the need to fix the lung in its natural state, i.e., filled with air. Any method used must be able to obtain the frozen specimen from the inflated lung. This requirement precludes the possibility of having a cryogen come into primary contact with the internal surface of an alveolus. However, if optimal fixation through the pleura could be attained, then the lining layers of subjacent alveoli could be studied. In this report, we describe a new method to cryopreserve distal lung tissue for optimal study of the extracellular lining layers of the alveolus. Alveolar tissue is sufficiently preserved in the inflated state to maintain its in vivo characteristics.