Effect of liner and core materials of plasterboard on microbial growth, spore-induced inflammatory responses, and cytotoxicity in macrophages.
Microorganisms, when grown on wetted plasterboards, can produce bioactive compounds capable of inducing inflammatory and toxic reactions in mammalian cells. The paper liner of plasterboard is commonly regarded as the major substrate for microbial growth. In this study, we cultured Stachybotrys chartarum, Aspergillus versicolor, Penicillium spinulosum, and Streptomyces californicus on liners and cores of plasterboards in order to examine the role of these main plasterboard components on microbial growth and the resulting bioactivity, which was assessed as the ability of microbial spores to induce inflammatory responses and to evoke cytotoxicity in mouse macrophages. The microbes, isolated from mold problem buildings, were grown under saturated humidity conditions on wetted liners and cores of six different plasterboards. The spores were collected, applied to RAW264.7 macrophages at different doses, and evaluated 24 h after exposure for their ability to evoke cytotoxicity and to stimulate production of nitric oxide (NO), tumor necrosis factor alpha (TNFalpha), and interleukin-6 (IL-6). In general, microbial growth was better on the cores than on the liners. All of the studied microbes collected from cores induced a dose-dependent production of TNFalpha in macrophages. The TNFalpha production stimulated by spores of Stachybotrys, Aspergillus, and Streptomyces paralleled their cytotoxicity. Spores of Streptomyces and Aspergillus collected from liners were among the most potent inducers of NO and IL-6. Good growth of Stachybotrys on cores was associated with high cytotoxicity. Penicillium grew only on cores, but it did not induce major inflammatory mediator productions, nor was it significantly cytotoxic. These results indicate that previously reported microbial growth on plasterboards and spore-induced production of important inflammatory mediators and cell death in macrophages is not only due to the paper liner of plasterboard, but the core material also has a crucial role.
Murtoniemi
Timo
T
National Public Health Institute, Department of Environmental Health, Kuopio, Finland. Timo.Murtoniemi@ktl.fi
Nevalainen
Aino
A
Suutari
Merja
M
Hirvonen
Maija-Riitta
MR
D000818:Animals; D001230:Aspergillus / Q000502:physiology; D002460:Cell Line; D002470:Cell Survival; D003252:Construction Materials / Q000009:adverse effects* / Q000382:microbiology*; D017077:Culture Media, Conditioned / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D015850:Interleukin-6 / Q000096:biosynthesis; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism / Q000382:microbiology; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis; D010407:Penicillium / Q000502:physiology; D013171:Spores, Bacterial / Q000502:physiology*; D013172:Spores, Fungal / Q000502:physiology*; D013191:Stachybotrys / Q000502:physiology; D013302:Streptomyces / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D017077:Culture Media, Conditioned; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide