The effect of subchronic exposure to the rubber vulcanization fumes on guinea pig lungs.

The influence of 28 days' inhalatory exposure to rubber vulcanization fumes at a concentration of 100 mg/m3 on guinea pigs' lung morphology was investigated. Focal infiltrations of pulmonary parenchyma with lymphocytes, neutrophilic and eosinophilic granulocytes and macrophages were observed. Lymphatic tissue concentrations having the typical appearance of solitary lymphatic nodules were also seen. The use of the double sequential Alcian blue/safranin O staining method for the identification of the mast cells [MCs] revealed that only Alcian-blue-positive MCs were observed, regardless of the region of the lungs examined, both in control and exposed guinea pigs. No safranin-0-positive MCs were seen. However, the MCs number increased from 1934 +/- 91 cells/mm3 tissue in controls to a statistically significant (p less than 0.05) 2486 +/- 89 cells/mm3 tissue in exposed guinea pig lungs. It was accompanied by histamine content increase from 1.50 +/- 0.06 micrograms/g wet tissue weight and 2.45 +/- 0.18 micrograms/g wet tissue weight, respectively. The distribution of the lung MCs varied, showing a statistically significant (p less than 0.05) increase in their number in the intraalveolar septa: from 957 +/- 53 to 1369 +/- 74 cells/mm3 tissue and in the peribronchial and peribronchiolar spaces: from 204 +/- 36 to 359 +/- 42 cells/mm3 tissue.