EFFETTI DELL'ESPOSIZIONE AL FUMO DI SIGARETTA SULL'OMEOSTASI DEL GLUTATIONE IN CELLULE DELL'EPITELIO RESPIRATORIO

Cigarette smoke extract (CSE) induces oxidative stress and causes decrease in intracellular glutathione’s levels (GSH). GSH plays a critical role in multiple cellular functions including cell cycle’s regulation and proliferation. Carbocysteine (S-CMC-Lys) is an antioxidant and mucolytic agent able to stimulate the secretion of GSH. The aims of this work were to: 1) determine the CSE effects on GSH intracellular levels and metabolism; 2) evaluate a possible S-CMC-Lys cytoprotective role against CSE induced effects in airway epithelial cells (16-HBE). Glutathione and reactive oxygen species (ROS) intracellular levels were evaluated by fluorimetry. The expression as well as the activity of enzymes involved in the GSH metabolic pathway were investigated by RT-PCR, Western blot and colorimetric assays. We found that CSE significantly increases cell mortality in a time and dose dependent manner, via an apoptosis-independent pathway. Short-term CSE exposure induces an increase in ROS levels and a GSH intracellular concentration drop. In parallel, the expression of glutathione peroxidases 2 and 3, glutathione reductase and glutamate-cysteine-ligase is increased. These effects can be partly reversed by S-CMC-Lys. These results suggest that S-CMC-Lys counteracts the oxidative stress induced by CSE and may be considered as a promising pharmacological tool in the treatment of diseases associated with cigarette smoking.