A preparation for the study of secretory function of the human bronchus in vitro.

Bronchi, not involved in tumor, were removed from resected human lungs. They were mounted in Ussing chambers containing Krebs-Henseleit solution with radiolabelled precursors of mucus. Airway was examined by both light and electron microscopy. Tissues recently removed from resected lungs exhibited both intra- and extra-cellular oedema and hypoxic changes in mitochondria, but tight junctions between epithelial cells appeared intact, indicating an effective epithelial barrier. Tissues removed from Ussing chambers after up to 6 h showed little oedema and their mitochondria were normal. Their appearance had returned to that of specimens taken that biopsy and fixed immediately. Autoradiographs of specimens from Ussing chambers showed that the mucus-producing cells had concentrated the radiolabels . Mucus in gland ducts was also radiolabelled. Damaged areas of mucous membrane were rare and probably pre-operative. We conclude that resected bronchi, suspended in Ussing chambers, have a structure and secretory activity suitable for investigations of the control of secretion.