The effect of ozone exposure on the release of eicosanoids in guinea-pig BAL fluid in relation to cellular damage and inflammation

Abstract

The observed effects after ozone exposure strongly depend on ozone concentration and exposure time. We hypothesized that depending on the O₃ exposure protocol, mainly either an oxidant damage or an inflammation will determine the O₃ toxicity. We compared two different ozone exposure protocols: an acute exposure (3 ppm 2 h) for studying the oxidant damage and an exposure (1 ppm 12 h) where an inflammatory component is also probably involved. We measured LDH activity and protein and albumin exudation as markers for cellular damage. After the acute exposure an increase in LDH activity was measured and after exposure to 1 ppm ozone for 12 h the exudation of protein and albumin was also enhanced. The histological examinations showed a neutrophilic inflammatory response only after exposure to 1 ppm ozone for 12 h. The acute exposure protocol resulted in an increased release of PGE₂, PGD₂, PGF_2α and 6-ketoPGF_1α whereas exposure to 1 ppm ozone for 12 h led to an additional release of LTB₄. No effects were measured on the release of TxB₂ and LTC₄/D₄/E₄. These changed amounts of eicosanoids will probably contribute to the ozone-induced lung function changes.