金属粉尘致肺纤维化的研究

Etiological Study on Pneumoconioses due to Metallic Dusts

我国矿源丰富、从事各种金属及其氧化物开采、生产、使用的接尘工人为数众多。长期以来对金属粉尘的生物学作用，特剐是致肺纤维化作用是争论的准点，有必要进行系统研究，提供阐明这一问题的论据，以便为确定我国职业病名单及制定相应的卫生标准和诊断标准等卫生立法服务。

Alang with the development of modern-ized industries, the metallic dust and its oxidewere used widely so that great attention sho-uld be paid to the biological effects and occu-pational hazards of the metallic dusts to theworkers. The fibrogenic effects of metallicdusts remains a problem in dispute, an invest-igation to focus on the fibrogenic effects ofaluminum oxides, ferrum oxide and hard metaldusts by industrial hygiene and epidemi-ological investigation, clinical examination,experimental studies and human histopathol-ogical observation were done in the recent 5years. The results and conclusions were as foll-ows. The biological effects of three metallic du-sts (aluminum oxide ferrum oxide, hard metal)were investigated. Studies were done on industrial hygiene,epidemiological investigation and clinical exa-mination, animal experiments and autopsystudy, the results shown as follows: Dust concentration and quartz content ofthe three metallic dust (aluminum oxide, ferrumoxide, hard metal) were 4. 6～182. 6, 215～1558and 3. 3～39mg/m^3, and 0.3～0.6, 8. 0 and 1.2～19.7% respectively; the prevalences were3.84%, 4. 84% and 0.64% separately; the lat-ency time were 26.4, 17. 3 and 25. 6 years. Clinical aspects: Symptoms: In 98 patients with pneumo-conioses (aluminum oxide: 51, ferrum oxide: 39,hard metal: 8), cough, expectoration, short-ness of breathe and stuffiness sensation in thechest, usually developped. X-ray appearance:irregular small opacities in aluminum oxideand hard metal pneumoconioses and roundedsmall opacities in ferrum oxide pneumo-conioses involving the middle and lower zonesand then the upper zones, profusion 1～2grade. without large shadow or pleural plaquesin all cases, some of them showed emphyze-matous signs. None of the patients werecomplicated pneumoconioses. Animal experiments in vivo 50, 80, 100 mg/rat intratracheally instillation, lung dry we-ight and collagen content in experimental gr-oups were evidently higher than control gro-up. Reticular and collagenic fibers were seenin the lung interstitial tissue; in vitro, survi-val rate of macrophages more reduced than control group. LDH in incubation fluid andhematolytic rate were higher than controlgroup. Autopsic study: The human pathologicalstudy was done in 2 cases of aluminum oxidepneumoconiosis and 3 cases of ferrum oxidepneumoconiosis. The histopathological featureis dust macular type. Etiological dust identified: aluminum oxi-de Al, Fe, Mn and so on were identified inthe lung tissue by Atomic absorption spectro-photometer, EDXA, X-ray difraction,The me-tal dust in lung tissue of workers exposed tothose metal dusts were higher than that ofunexposed (for example, ferrum oxide increaced10～100 fold). The content of quartz dust wassomewhat similar to that of unexposed work-ers and lower than that of patients with silic-osis or silicatosis Besides γ-aluminum oxidedust has the fibrogenic effect, the α-aluminumoxide dust (for example, brown corundum)also has mild fibrogenic effect in aluminiumoxied pneumoconiosis; ferrum oxide and Mn fo-und in lung tissue of ferrum oxide pneumoconi-osis,tungsten carbide takes effect in combinati-on with cobalt in hard metal pneumoconiosis,the effect of quartz have not been proven inall cases. The new notions about the fibrogenic eff-ect of these three metallic dusts were the firstreport in the literatere. It has to break throu-gh in the level of understanding of the me-tallic pneumoconioses and it will certainly en-lighten deeply study on fibrogenic effect ofmetallic dusts, and could provide more usefulinformation for setting up the hygienic standa-rds and diagnostic criteria of pneumoconioses.