| Abstract: | Effects of 10 ppm nitrogen dioxide (NO2) exposure on the contents of prostaglandins (PGs) and thromboxane (TX) B2 in broncho-alveolar lavage (BAL) of rats were studied. In the BAL of normal rats, the amounts of PGs and TXB2 in the whole lavage were 6-keto-PGF1α (38.0 ± 6.4 ng) > TXB2 (11.8 ± 4.0 ng) > PGF2α (5.7 ± 1.6 ng) PGE (0.5 ± 0.3 ng). Rats were exposed to NO2 for 1, 3, 5, 7 and 14 days. The NO2 exposure decreased in the level of 6-keto-PGF1α by about 35% throughout the exposure. The level of TXB2 was higher in the day 5 exposure group (155%). The contents of PGF2α and PGE first, decreased and then transiently increased on days 3 and 5. PG 15-hydroxy-dehydrogenase activity of lung homogenate decreased correspondingly on day 3 and 5. Then the contents PGF2α and PGE decreased on day 7 and 14.6-keto-PGF1α and TXB2 are stable metabolites of PGI2, a strong bronchorelaxant and TXA2, a strong bronchoconstrictor respectively. Therefore the results suggested that the decrease in 6-keto-PGF1α, a major prostanoid in the BAL and the increase in TXB2 may correlate with broncho constriction by NO2 exposure. |
