Growth conditions of streptomyces anulatus regulate induced inflammatory responses and cyto toxicity in macrophages
Maija-Riitta Hirvonen Ph.D., Merja Suutari Ph.D., Ulla
Lignell M.Sc, Marjo Ruotsalainen Ph.D. Aino Nevalainen Ph.D.
Division of Environmental Health, National
Public Health Institute, Division of Environmental Health P.O.Box 95,
FIN-70701 Kuopio, Finland. Correspondence: Maija-Riitta Hirvonen, Ph.D,
National Public Health Institute, Division of Environmental Health,
Laboratory of Toxicology, P.O.Box 95, FIN-70701 Kuopio, Finland, Telephone
+358 17 201 303, Telefax +358 17 201 265, E mail Maija-Riitta.Hirvonen@ktl.fi
RAW264.7 macrophages were exposed for 24 hrs to the spores of Streptomyces anulatus (doses of 105 106, 107 spores/million cells), isolated from a moldy building and grown on 23 different kind of media. Production of nitric oxide (NO) in macrophages was induced dose dependently by spores of S. anulatus reaching the level from 4.2 mM to 39.2 mM depending on the composition of the medium. The expression of inducible NO synthase (iNOS) was detected in the macrophages after the exposure to the spores collected from all tested growth media. The production of reactive oxygen species (ROS) was significantly increased when compared to controls by the highest dose of the spores from two media. The growth media affected the production of cytokines as well; the highest dose dependent levels of IL-6 varied from 400 to 7500 pg/ml and the levels of TNF a from 450 to 3100 pg/ml. The amount of death macrophages after the exposure varied from 11 % to 98% depending on the growth media of the microbe. Altogether, our results suggest that the growth conditions of S. anulatus, have a fundamental role in the ability of spores to induce inflammatory responses and cytotoxicity in RAW264.7 cells.