Abstract

This study determined plasma and liver tissue benzene, toluene, ethylene and xylene (BTEX), malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD) and glutathione peroxidase (GPx) status in rats orally exposed to gasoline. Sixteen adult male Wistar rats (210.0 ± 20.0 g), distributed into control and test groups, of eight rats each were used. Rats in test group were administered 2.0 mLkg-1 body weight gasoline for sixty days, while control rats were given distilled water. The animals were sacrificed after exposure period, and relevant tissues collected and processed for analyses. BTEX concentrations in plasma and liver tissue homogenates were determined by gas chromatography with flame ionized detector (GC-FID), while SOD and GPx activities, as well as MDA and GSH levels were determined by standard spectrophotometric methods. The results showed a significantly (p<0.05) higher plasma and liver tissues BTEX concentrations in test rats, compared to the control. This shows that BTEX are among the gasoline hydrocarbons that are largely absorbed from the gastrointestinal tract (GIT), and distributed within the blood and liver tissues. Also, the levels of plasma and liver tissue MDA were significantly (p<0.05) higher, while SOD, GPx, and GSH status were significantly lower in test rats, compared respectively to control; an indication of gasoline-induced oxidative stress. These results suggest that the raised plasma and liver tissue MDA, and reduced SOD, GPx and GSH activities in test animals may be attributed to the raised tissue BTEX levels; concluding that BTEX, and/or their metabolites, are implicated in gasoline-induced oxidative stress in rats.

Key words: Gasoline, oxidative stress, benzene, toluene, ethylene and xylene (BTEX), rats.