[Biological and histological changes induced by cement dust]

In animal experiments pneumoconiogenic properties of metallurgic and Portland cement dust, produced in Poland, were investigated. Experimental pneumoconiosis was developed by intratracheal single administration, to white rats, of 50 mg of dust suspended in 0.6 ml of NaCl physiological solution. The control groups were composed of animals to whom intratracheally physiological NaCl solution, TiO2 dust and two quartz dusts of varying fibrogenic properties--weak and mild, were administered. The content of crystalline silica, as determined chemically, was approx. 3% in both cement samples. X-ray diffraction did not show any content of crystalline phases in the cements, TiO2 dust contained rutile, whereas both quartz dusts contained about 100% alpha-quartz. After 3 months the animals were sacrificed. Wet lungs weight and hydroxyproline content in lungs were determined. In addition, mediastinal nodes and lungs were examined histologically. Cement dust was found to exhibit weak fibrogenic properties, not different significantly from fibrogenic properties of inert TiO2. Nevertheless increases in fibrogenic effect of cement dusts were significantly higher as compared to the control group (geometric mean hydroxyproline content in the control group was 2.52 +/- 0.06 mg, 4.50 +/- 0.09 in the Portland cement and 4.88 +/- 0.06 in metallurgic cement. Histological changes in lungs, due to cement effect are not progressive, expressing merely inflammatory reaction to dust. Nevertheless despite weak fibrogenic properties the cement dust provokes lesions of macrophages in lungs.