Role of Surfactant Protein-A in Nitric Oxide Production and Mycoplasma Killing in Congenic C57BL/6 Mice

• Published in: American journal of respiratory cell and molecular biology Vol. 30; no. 3; pp. 319 - 325
• Main Authors: Hickman-Davis, Judy M, Gibbs-Erwin, Julie, Lindsey, J. Russell, Matalon, Sadis
• Format: Journal Article
• Language: English
• Published: United States Am Thoracic Soc 01-03-2004; American Thoracic Society
• Subjects: Animals; Bronchoalveolar Lavage; Cells, Cultured; Cytokines - metabolism; Genotype; Lung - microbiology; Mice; Mice, Congenic; Mice, Inbred C57BL; Mice, Knockout; Mycoplasma Infections - metabolism; Mycoplasma pulmonis - physiology; Nitrates - metabolism; Nitric Oxide - biosynthesis; Nitrites - metabolism; Pulmonary Alveolar Proteinosis - metabolism; Pulmonary Surfactant-Associated Protein A - genetics; Pulmonary Surfactant-Associated Protein A - physiology
• ISSN: 1044-1549; 1535-4989
• DOI: 10.1165/rcmb.2003-0246OC

We generated congenic surfactant protein A (SP-A)-deficient (SP-A[-/-]) mice on the mycoplasma resistant C57BL/6 background (B6.SP-A[-/-]) and characterized their response to mycoplasma infection in comparison to C57BL/6 (B6) mice. B6.SP-A(-/-) mice infected with 10(6) colony-forming units (cfu) of Mycoplasma pulmonis had significantly higher bacterial lung loads than B6 mice at 72 h postinfection (p.i.). At the higher infection dose of 10(7), B6.SP-A(-/-) mice had significantly higher lung cfu at 24 h; however, no difference in mycoplasma cfu was observed between B6 and B6.SP-A(-/-) mice at 48 and 72 h p.i. We found that uninfected B6 mice had lower bronchoalveolar lavage nitrite (NO(2)(-)) and nitrate (NO(3)(-)) levels as compared with B6.SP-A(-/-) mice. On the other hand, infection of B6 mice with mycoplasmas resulted in significantly higher bronchoalveolar lavage NO(2)(-) and NO(3)(-) as compared with B6.SP-A(-/-) mice. These data indicate that SP-A may help regulate NO production in response to a specific stimulus, i.e., suppression of NO in the absence of bacteria and increased NO in the presence of bacteria. These data indicate that the contribution of SP-A to mycoplasma killing may be limited to lower doses of pathogens.