Short-term exposure of mice to gasoline vapor increases the metallothionein expression in the brain, lungs and kidney

Abstract

Environmental airborne pollution has been repeatedly shown to affect multiple aspects of brain and cardiopulmonary function, leading to cognitive and behavioral changes and to the pronounced inflammatory response in the respiratory airways. Since in the cellular defense system the important role might have stress proteins-metallothionein (MT)-I and MT-II, which are involved in sequestration and dispersal of metal ions, regulation of the biosynthesis and activities of zincdependent transcription factors, as well as in cellular protection from reactive oxygen species, genotoxicity and apoptosis, in this study we investigated their expression in the brain, lungs and kidney, following intermittent exposure of mice to gasoline vapor. Control groups consisted of intact mice and of those closed in the metabolic chamber and ventilated with fresh air. The data obtained by immunohistochemistry showed that gasoline inhalation markedly upregulated the MTs expression in tissues which were directly or indirectly exposed to toxic components, significantly increasing the number of MT I+II positive cells in CNS (the entorhinal cortex, ependymal cells, astroglial cells in subventricular zone and inside the brain parenchyma, subgranular and CA1-CA3 zone of the dentate gyrus in hippocampus and macrophages-like cells in perivascular spaces), in the lungs (pneumocytes type I and type II) and in the kidneys (parietal wall of Bowman capsule, proximal and distal tubules). The data point to the protective and growth-regulatory effects of MT I + II on places of injuries, induced by inhalation of gasoline vapor.