Respiratory Effect of Selected Asbestos Substitute Mineral Fibres - Using as Insulation Materials in Building Industry

The effects of industrial fibrous dusts on the respiratory system represents a potencial environmental and occupational health hazard for humans. Long time of asbestos exposure can cause pleural plaques, asbestosis and oncological diseases. From these facts follow important tasks on the deep and broad research activities aiming at the study of the effects of fiber substitutes. The aim of the present work was to find out the influence of asbestos and asbestos substitute mineral fibres (ASMF) on selected bronchoalveolar lavage fluid (BALF) inflammatory and cytotoxic parameters as well as dose and time dependence of studied fibrous dust effect. The 2 types of substitutes (rock wool, glass fibers) as well as amosite asbestos were intratracheal instilled at 2 doses (2 and 8 mg/animal). Following parameters in bronchoalveolar lavage fluid after 4 and 16 week exposure were investigated: Inflammatory response parameters: The number of leukocytes / ml, the number of alveolar macrophages (AM) / ml, the differential number of cells (% AM; Gr; Ly). Cytotoxic parameters: Phagocytic activity of AM, viability of AM, the lactate dehydrogenase activity, the acid phosphatase activity, the cathepsin D activity (in the cell-free lavage fluid and in the BAL suspension). Sequential arrangement of examined fibrous dust according to their harmfulness from the point of view of inflammatory and cytotoxic parameters after intra tracheal instillation: Amosite > Rockwool > Glass fibers. Hurbánková M*, Černá S and Moricová S Department of Public Health, Slovak Medical University, Slovak Republic Hurbánková M, et al., Journal of Respiratory Medicine and Lung Disease Remedy Publications LLC. 2018 | Volume 3 | Issue 1 | Article 1033 2 There is thus a necessity to substitute asbestos by fibres technologically similar, but with less biological effects. From these facts follow important tasks on the deep and broad research activities aiming at the study of the effects of fiber substitutes. The mechanism of action of asbestos and other fibrous structures substitutesare still not clearly understood. Many industrial dusts (asbestos substitutes) are used as insulating materials for thermal insulating of buildings. The aim of the present work was to find out the influence of asbestos and asbestos substitute mineral fibres (ASMF) on selected bronchoalveolar lavage fluid inflammatory and cytotoxic parameters as well as dose and time dependence of studied fibrous dust effect. Further on, our results are used for legislative purposes to amend the MAC (maximum allowable concentration on the workplace and environmental) of fiber dusts in the workplace air as well as to find out the suitability of the particular fiber substitute for asbestos. Our results provided and will also provide a basis for manufacturers and makers to select for production and processing biologically acceptable materials. In addition to it, our results can be used for better understanding of environmental health in given specific field and of health protection of the inhabitants in the respective area [4-8]. Methods The 2 types of ASMF (rockwool, glass fibers) as well as amosite asbestos were instilled at 2 doses (2 and 8 mg/animal). Animals (number: 8 per group) were intratracheally instilled (noninvasively) with fibrous suspension (2 mg suspended in 0,2 ml of saline solution per animal) or only with 0,2 ml saline per animal (control group). Dose 8 mg was divided and instilled 4 times (weekly 2 mg/0,2 ml saline solution). After sacrifice (4 or 16 weeks after last intratracheal instillation the animals were anesthetised with thiopental –150 mg/ kg of animal) cells were harvested by bronchoalveolar lavage (BALF). The trachea was cannulated, and the lungs were washed 5 times with 4 ml of saline solution (in situ). Following parameters of BALF were investigated: a) Inflammatory response biomarkers: the number of BALF cells / ml, the number of alveolar macrophages (AM) / ml, the differential number of cells (% AM and neutrophils). b) Cytotoxic parameters: phagocytic activity of AM, viability of AM, lactate dehydrogenase activity (in the cell-free lavage fluid), acid phosphatase activity (in the cell-free lavage fluid and in the BAL suspension), alkaline phosphatase activity (in the cell-free lavage fluid), cathepsin D activity (in the cell-free lavage fluid and in the BAL suspension). The methods are described in more detail in the paper [9]. The length (L) and diameter (d) of fibres in our intratracheal instillation study are following: Amosite: length (μm) % fibres mean diameter (μm) < 20 5 0.71 20-30 75 >30 20 Rockwool: L: 16.5 μm (SD: 2.51) d: 1. 8 μm (SD: 2.32) Glass fibers: (MMVF 10): L: 22.6 μm (SD: 13.6) d: 1.31 μm (SD: 0.85) The results were statistically evaluated using Mann Whitney`s test. Discussion At present, the question of the toxicity of asbestos substitutes is an area of extensive research. However, there is only limited knowledge concerning the biological effects of these fibres. The processes which lead to morphological changes of the lungs after long-term exposure to some industrial mineral fibrous dusts are still not clear, they involve many molecular and cellular reactions, including an inflammatory response and cytotoxicity. Fiber length has been found to be the major predictor of the ability of industrial fibers of different types to Intratracheal instillation. Exposure: Dose: 4 weeks 16 weeks