Histological study on the effect of gasoline on guinea pig epidermis: can flavonoid extract reverse this effect?

Introduction: Car fuel, containing gasoline, is reported to have an irritative effect on mammalian skin.Objectives: This study aimed to detect the cellular changes in the epidermis of male guinea pig back skin evoked by repeated exposure to gasoline and to evaluate the role of flavonoid extract in reversing these changes.Materials and methods: Thirty-five guinea pigs, divided into a control (n=5) group I and an experimental (n=30) group II were used. The latter was divided into two subgroups; the guinea pigs in the first subgroup (group IIa) were painted with gasoline twice daily for 21 days and those in the second (group IIb) were treated with flavonoid extract after previous gasoline dermal application. Animal skin was dissected and processed for light and electron microscopic examination; further, statistical analysis was performed to compare the epidermal thickness in different groups.Results: Naked eye examination of skin of guinea pigs in group IIa showed erythema and ulceration. In addition, a significant increase in epidermal thickness was observed by light microscopy. Ultrastructural changes include an ill-defined dermo-epidermal junction and basal layer cells showing an electron-dense cytoplasm, increased lysosomal dense bodies, and swollen mitochondria. Their nuclei showed an irregular nuclear envelope and peripheral chromatin condensation. The prickle layer cells showed dissolution of desmosomal junctions and cytoplasmic vacuolation. Granular cell layers showed a marked decrease in fibrillar contents and the horny layer showed separation of individual layers by flocculent-filled spaces. The flavonoid-treated group showed a significant decrease in epidermal thickness (compared with the gasoline-painted group) and most of the epidermal cells appeared normal with intact nuclei.Conclusion: Safety measures, as well as orientation programs, are recommended for car fuel-filling workers exposed to continuous contact with gasoline, to avoid its drastic effect on skin. Application of flavonoid orange extracts is recommended as they ameliorate this effect