The search for stem cells of the epithelium in pulmonary alveoli

In recent years significant progress has been witnessed in the identification of stem cells, which have now also been identified in the lungs. The aim of this was to induce post-pneumonia alveolar regeneration to facilitate the identification of stem cells. The studies were performed on Buffalo strain rats. Pneumonia was induced in the animals by a sub-pleural injection of carragenin. On days 4, 5 and 10 of the experiment both the control and experimental animals received intraperitoneal injections of bromodeoxyuridine (BrdU). Twenty-four hours after the last BrdU injection the rats were sacrificed and samples of the lungs were taken for examination. In order to detect proliferating cells in the paraffin sections, BrdU incorporation was detected with monoclonal antibodies. In pilot experiments BrdU incorporation was demonstrated in individual alveolar cells of variable distribution and of variable intensity in the colour reaction. The results have confirmed the existence of stem cells in pulmonary alveoli but their closer characterisation requires further studies with other techniques to detect pulmonary stem cells.