Connexin43 plays an important role in lung development

Objectives: Connexin43 (Cx43) is one of the proteins associated with gap junction. Connexin43 knockout mice die after birth owing to hypoplastic lungs. The purpose of this study was to analyze the hypoplastic lung of Cx43 knockout mice to clarify the role of the Cx43 during lung development. Methods: Adult hetero Cx43 mice were mated. Newborn mice were divided into the following groups: wild, hetero, and knockout. Total RNA was extracted from the right lung, and the left lung was fixed for immunohistochemical staining. The mRNA expression of surfactant protein C, aquaporin-5, and a-smooth muscle actin were analyzed by reverse transcriptase polymerase chain reaction. H&E and immunohistochemical staining for those markers were performed. Results: The mRNA expression of aquaporin-5, surfactant protein C, and alpha-smooth muscle actin was significantly lower in knockout mice than that in the wild and hetero mice. H&E staining in the knockout mice showed narrow airspaces and thicker interalveolar septae. Immunohistochemical staining in all markers showed the formation of alveoli to be delayed in the knockout mice. Conclusion: Based on these findings, Cx43 is closely related to alveolar and vascular formation during lung development. (C) 2009 Elsevier Inc. All rights reserved.