Evaluation of cytotoxic, oxidative stress, proinflammatory and genotoxic responses of micro- and nano-particles of dolomite on human lung epithelial cells A(549).
Dolomite is a natural mineral of great industrial importance and used worldwide, thus millions of workers are at risk of occupational exposure. Its toxicity is however, meagerly documented. In the present investigation, a dolomite powder obtained from its milling unit was analyzed by some standard methods namely, optical microscopy, transmission electron microscopy and dynamic light scattering. Results showed that dolomite powder contained particles of different shapes and size both microparticles (MPs) and nanoparticles (NPs), suggesting potential occupational exposure of these particles. An attempt was therefore, made to investigate dolomite toxicity in a particle size-dependent manner in human lung epithelial cells A(549). The comparative toxicity evaluation of MPs and NPs was carried out by assessing their effects on cell viability, membrane damage, glutathione, reactive oxygen species (ROS), lipid peroxidation (LPO), micronucleus (MN) and proinflammatory cytokines, namely tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). These markers of cytotoxicity, genotoxicity and inflammation were assayed in cells exposed to MPs and NPs in a dose-and time-dependent manner. Invariably, their toxic effects were dose-and time-dependent while NPs in general were significantly more toxic. Notably, NPs caused oxidative stress, genotoxicity and inflammatory responses, as seen by significant induction of ROS, LPO, MN, TNF-α, IL-1β and IL-6. Thus, the study tends to suggest that separate health safety standards would be required for micrometer and nanometer scale particles of dolomite.
Fibre Toxicology Division, CSIR-Indian Institute of Toxicology Research, M.G. Marg, P.O. Box 80, Lucknow 226 001, U.P., India; Department of Medical Elementology and Toxicology, Jamia Hamdard, New Delhi 110 062, India.
Govil
G
Patil
Department of Dermatology, University of Wisconsin, Medical Sciences Center, 1300 University Avenue, Madison, WI 53706, USA.
Mohd Imran
MI
Khan
Analytical Chemistry Division, CSIR-Indian Institute of Toxicology Research, M.G. Marg, Lucknow 226 001, U.P., India.
Devendra Kumar
DK
Patel
Department of Medical Elementology and Toxicology, Jamia Hamdard, New Delhi 110 062, India.
Sarwat
S
Sultana
Uttar Pradesh Rural Institute of Medical Sciences and Research, Saifai, Etawa, India.
Rajendra
R
Prasad
Fibre Toxicology Division, CSIR-Indian Institute of Toxicology Research, M.G. Marg, P.O. Box 80, Lucknow 226 001, U.P., India. Electronic address: ahmadi@sify.com.
Iqbal
I
Ahmad
D002119:Calcium Carbonate / Q000737:chemistry* / Q000633:toxicity*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D016207:Cytokines / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008168:Lung / Q000166:cytology; D008274:Magnesium / Q000737:chemistry* / Q000633:toxicity*; D015162:Micronucleus Tests; D053758:Nanoparticles / Q000633:toxicity*; D018384:Oxidative Stress; D010316:Particle Size; D011208:Powders; D017382:Reactive Oxygen Species / Q000378:metabolism
D016207:Cytokines; D011208:Powders; D017382:Reactive Oxygen Species; D007770:L-Lactate Dehydrogenase; D005978:Glutathione; D002119:Calcium Carbonate; D008274:Magnesium; C028042:calcium magnesium carbonate