Immunofluorescence evaluation of 4-hydroxynonenal and 8-hydroxy-2-deoxyguanosine activation in zebrafish (Daino rerio) larvae brain exposed (microinjected) to propyl gallate.

Propyl gallate (PG) is a chemical compound obtained by esterification of propanol with gallic acid. Due to its antioxidative properties, it is widely used in cosmetics and pharmaceutical industries as well as to protect the oils in foods such as butter, milk-based desserts, chewing gum, mayonnaise, meat, soups, cereals, spices and seasonings from rancidity. This study has been designed to assessment 8-OHdG and 4-HNE activity, and histopathological changes in the brain tissues of zebrafish larvae, which is a lecithotrophic organism, after 96 h of PG exposure via microinjecting to yolk sac of embryo. To this end, approximately 5 nL of various concentrations of PG (1, 10, and 50 ppm) has been injected into yolk sac of fertilized embryo (final exposure concentrations are 5, 50, 250 pg/egg) with micro manipulator system. After 96 h exposure time, propyl gallate caused immunofluorescence positivity of 8-OHdG and 4-HNE in the brain tissues of zebrafish larvae. PG was not effect brain tissue histopathological in low concentrations (1 and 10 ppm) but highest concentration (50 ppm) caused degenerative changes in brain. These results suggests that PG treatment could lead oxidative DNA damage by causing an increase 8-OHdG and 4-HNE activities. This strategy will enable us to better understand the mechanisms of propyl gallate in brain tissues of zebrafish larvae.