| Objectives The purpose of this thesis was to analysis the?-SiO2 content,composition,dispersion,morphology,and free radical content of dust in the alveolar and in work place.We explored the possible changes in the properties?especially the pathogenicity?of dust after it entered the lung.Methods We collected and filtered dust from HanDan coal mine tunnelling areas.We used a 400 mesh sieve screened and recycled dust in the water.We set up five dust groups and one saline group.The dust was configured as a suspension of 50 mg/ml.Each dose was 1ml dust suspension or 1ml normal saline.Rats were exposed to dust by non-tracheal exposure method 8 times week by week.The lung tissues and alveolar dust of the rats in the dust-exposure group were collected after 1W,4W,8W,14W,and 20W,respectively.The lung tissues of the rats in the saline group were collected.Lung tissue was used to make pathological sections of HE staining,for monitoring the progress of silicosis.We detected the properties of two types of dust and compared them:The content of free silica in dust was measured by infrared spectrophotometer,the morphology of dust was observed by field emission scanning surface electron microscope,and the dispersion of dust was counted by optical microscope.The contents of iron,aluminum,magnesium,zinc,copper,manganese,cadmium,nickel,lead,arsenic,chromium,silicon and antimony in dust were determined by ICP-MS,and the ability of releasing hydroxyl radical in phosphate buffer was determined by fluorescence spectrophotometer.Results 1 Rats'fur had no gloss,failed to act quickly after20 weeks dust treatment.Visually,there were milky punctate lesions on the surface of the lungs with sand graininess,and fibroblasts arranged concentric circle and typical silicon nodules appeared in the HE stained sections of the lung tissue.Normal appearance and behavior of rats in saline group,soft and tender surface of rat lung were observed by naked eye.HE stained sections showed normal lung tissue structure,thin alveolar wall and no inflammatory reaction.2 The content of?-SiO2 in dust and lung lavage dust was measured by infrared spectrophotometer.In the field dust group,1 W group and 4 W group after exposure to dust,the lung tissue structure was normal,the alveolar wall was thin,and no inflammation reaction accured.The levels of?-SiO2 were 37.27%,37.26%,37.26%,37.25%,37.26%,37.25%,respectively.There was no significant difference in?-SiO2 content among the three groups?P<0.05?.3 Inductively coupled plasma?ICP-MS?was used to detect the contents of 13 elements in dust and lung lavage dust.The content of Fe increased gradually with the time of dust exposure passed.While the other 12 elements-Al,Mg,Si,Pb,Mn,Ni,Zn,Cu,Cr,Sb,Cd,AS,decreased compared with the field dust group,4 Using laser confocal scanning electron microscope?LSCM?to photograph the morphology of dust,it could be seen that the shape of dust in the field is mostly spherical,and the shape of dust extracted from lung lavage fluid of rats is mostly massive and angular.A few dust edges are sharp.5 The percentage of dust dispersion in the range of X?2?m?2?m<X?5?m?5?m<X?10?m?X>10?m was 42.17%,36.17%,17.00%,4.67%.At 1 week,4 weeks,8 weeks,14 weeks and 20 weeks after exposure to dust,the diameter of the dust from lung lavage was more than 90%,and the size of dust in the range of 5?m<X?10?m accounted for 2%to 3.33%,and that of the dust from lung lavage was less than 5?m,and the size of the dust was less than 5?m.6 Using a fluorescence spectrophotometer to detect the ability of dust to release hydroxyl radicals,The amount of hydroxyl radical released from the site dust is 4.54×10-3?g/mg.The amount of hydroxyl radicals released by the lung lavage dust is 5.45×10-3?g/mg?5.50×10-3?g/mg?5.71×10-3?g/mg?5.60×10-3?g/mg?5.59×10-3?g/mg on 1 week,4 weeks,8 weeks,14weeks,20 weeks after dusting.The amount of hydroxyl free released from rat lung lavage dust in phosphate buffer solution was higher than on-site dust,and the amount of hydroxyl free released from lung lavage dust was the highest at 8 weeks after exposure.Conclusions 1 The content of?-SiO2 did not change when dust entered the organism.2After dust entering the organism,the content of Fe increased gradually with the time of dust exposure.Al,Mg,Si,Pb,Mn,Ni,Zn,Cu,Cr,Sb,Cd,The content of AS decreased.3 The irregular dust particles were more likely to stay in the lungs.4 When the dust entered the body,the dust>5?m was excreted out of the body,and the dust particles?5?m could enter the alveoli and bronchioles.The particle size of lung lavage dust?5?m accounted for more than 90%.5 The ability of dust in lung lavage fluid to produce hydroxyl radical in phosphate buffer solution was higher than that in workplace.Figure9;Table8;Reference 154... |
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