Influence Of Early Growth Response 1 (Egr1) And Tenascin C (Tnc) On Compensatory Lung Growth

Abstract

Mice that underwent a unilateral pneumonectomy (PNX) show complete restoration of pulmonary function through a rapid and complete compensatory growth of the remaining lung. Currently there is still little known about the nature, initiation and modulation of such growth. Microarray studies showed an upregulated expression of the immediate early gene Egr1 and the matricellular protein Tnc after PNX. In this study we assess the role of Egr1 and Tnc in early stages of compensatory lung growth. Stereology analysis of tissue sections showed that lungs of Egr−/− mice have the same surface area but less alveoli and a larger lung volume compared to wild type mice. During compensatory lung growth the loss of Egr1 seems to lead to a delayed regeneration of alveolar surface area whereas lung volume increases faster. Stereological analysis of Tnc−/− mice showed that these mice also have a larger lung volume compared to wild type mice. After PNX regeneration of alveolar number and lung volume is impaired. The results indicate that Egr1 and Tnc seem to have an influential role in the initial phases of compensatory lung growth. Additional experiments will be done to clarify how these genes are regulated after PNX. German research foundation.