Role of surfactant protein-A in nitric oxide production and mycoplasma killing in congenic C57BL/6 mice.
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.
Hickman-Davis
Judy M
JM
Department of Anesthesiology, University of Alabama at Birmingham, UAB Dept. of Anesthesiology, 1530 3rd Ave. South, Birmingham, AL 35294-2172, USA.
Gibbs-Erwin
Julie
J
Lindsey
J Russell
JR
Matalon
Sadis
S
D000818:Animals; D018893:Bronchoalveolar Lavage; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D005838:Genotype; D008168:Lung / Q000382:microbiology; D051379:Mice; D020297:Mice, Congenic; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009175:Mycoplasma Infections / Q000378:metabolism*; D045803:Mycoplasma pulmonis / Q000502:physiology*; D009566:Nitrates / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis*; D009573:Nitrites / Q000378:metabolism; D011649:Pulmonary Alveolar Proteinosis / Q000378:metabolism; D037662:Pulmonary Surfactant-Associated Protein A / Q000235:genetics / Q000502:physiology*
D016207:Cytokines; D009566:Nitrates; D009573:Nitrites; D037662:Pulmonary Surfactant-Associated Protein A; D009569:Nitric Oxide