Evaluation of the effects of toluene inhalation on alveolar epithelial permeability by 99mTc-DTPA inhalation scintigraphy in automobile painters

Abstract

The main component of paint thinner used in industry is toluene diisocyanate (TDI) which can cause occupational asthma in 5-10% of exposed workers. To investigate the effect of TDI on 99mTc clearance rate of alveolar epithelium and on pulmonary function tests (PFT) in automobile painters, and to determine the relationship between 99mTc-DTPA radioaerosol lung scintigraphy and serum levels of antioxidant enzymes and metalloproteinases (MMPs) of automobile painters. Twenty-eight automobile painters and 13 control subjects were included in the study. 99mTc-DTPA aerosol inhalation scintigraphy and PFT were administered to all subjects. Clearance half-time (T1/2) and penetration index (PI) on the first-minute image after 99mTc-DTPA scintigraphy were calculated. Blood levels of MDA, antioxidant enzymes and metalloproteinases were measured. The mean T1/2 values of automobile painters were longer in both smoker and non-smoker subjects, but the difference was not significant (P>0.05). Although the PFT values decreased in automobile painters, there was no significant difference between each group. Any correlation between spirometric measurements and T1/2 or PI values in non-smoking automobile painters was not detected. Negative correlation among mean T1/2 value and FVC% and FEV1% in smoking automobile painters, and positive correlation between mean T1/2 value and MMP-9, GSH-Px levels in non-smoking automobile painters were detected. Our results suggested that the clearance of 99mTc-DTPA from the lungs of automobile painters was slower than in the control group, but the difference is not statistically significant. This data also supports the observation that TDI occasionally stimulates bronchial changes rather than alveolar changes in automobile painters.