Effects of Ozone Exposure in Rats on Memory and Levels of Brain and Pulmonary Superoxide Dismutase

Exposure to ozone results in increased production of free radicals, which causes oxidative stress. The objective of this study was to determine the effect of different doses of ozone exposure on memory and to correlate this with pulmonary and brain Cu/Zn superoxide dismutase (SOD) levels. Male Wistar rats were exposed for 4 h to one of the following ozone concentrations: 0, 0.1, 0.2, 0.5, or 1 ppm. Subsequently, they were tested in a passive avoidance conditioning protocol to measure short and long-term memory. Motor activity was determined 1 and 24 h after ozone exposure. Cu/Zn SOD levels in the brain and pulmonary tissue were also measured. Rats exposed for 4 h to 0.2, 0.5, and 1 ppm ozone showed long-term memory deterioration and decreased motor activity, which was reversed 24 h later. Brain and pulmonary Cu/Zn SOD levels were increased in animals exposed to 0.1, 0.2, and 0.5 ppm ozone doses, but decreased in animals exposed to 1 ppm ozone. The results suggest that ozone exposure affects long-term memory possibly in association oxidative stress.