Upregulation of galectin-3 by Corynebacterium kutscheri infection in the rat lung

Corynebacterium (C) kutscheri and Staphylococcus aureus were isolated from two Sprague-Dawley (SD) rats with a hemisected spinal cord. Grossly, gray-white bulging foci and abscesses were distributed throughout the parenchyma of the lung. Pathologically, severe necrotizing lobar pneumonia with abscesses and fibrinous pleuritis were observed. Immunohistochemical analysis found accumulation of galectin-3 in alveolar macrophages and the alveolar interstitial region. No other viral or bacterial pathogens were detected in these animals. In addition, similar pathogenic changes and accumulation of galectin-3 were observed in the lungs of SD rats experimentally infected with C. kutscheri. Using northern blot analysis, the relative galectin-3 and GAPDH mRNA levels were 4.6 to 9.3 times higher in C. kutscheri-infected lung than in uninfected controls. These results demonstrate that a single C. kutscheri infection can induce the upregulation of galectin-3 in the lung and that this molecule may have an important pathogenic role in C. kutscheri infections in rats.