Rat surfactant apoprotein A (SP-A) exhibits antioxidant effects on alveolar macrophages.
The effects of surfactant apoprotein A (SP-A) on the superoxide production of rat alveolar macrophages (AM) were studied. Superoxide production was measured by the ferricytochrome c reduction method. When AM were incubated with SP-A only during the measurement of superoxide production, superoxide production was not influenced by SP-A. However, when AM were preincubated with SP-A at a concentration of 1, 2, and 10 micrograms/ml, superoxide production by AM was significantly inhibited (P < 0.05, P < 0.01, P < 0.01, respectively). The superoxide production of AM stimulated by PMA was significantly inhibited by SP-A at a concentration of 1 microgram/ml (P < 0.01), and superoxide production stimulated by zymosan was also inhibited by SP-A at a concentration of 10 micrograms/ml (P < 0.05). Suppression of superoxide production of unstimulated and PMA-stimulated AM was significantly inhibited by anti-SP-A antibody. Superoxide generation by the xanthine and xanthine oxidase system was not affected by the presence of SP-A. Our results suggest that superoxide production of AM can be inhibited by SP-A and that this inhibitory effect on AM is due to a specific effect of SP-A. From these results, it is speculated that SP-A may have a protective role for oxidant injury by AM in the lung.
Katsura
H
H
First Department of Internal Medicine, Tokyo Women's Medical College, Japan.
Kawada
H
H
Konno
K
K
D000818:Animals; D001059:Apoproteins / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D016676:Macrophages, Alveolar / Q000378:metabolism*; D008297:Male; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013045:Species Specificity; D013481:Superoxides / Q000378:metabolism*; D014969:Xanthine Oxidase / Q000378:metabolism
D001059:Apoproteins; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; C046616:pulmonary surfactant apoprotein; D013481:Superoxides; D014969:Xanthine Oxidase