Role of propolis on oxidative stress in fish brain

Cypermethrin causes its neurotoxic effect through voltage-dependent sodium channels and integral protein ATPases in the neuronal membrane. Brain and nerve damage are often associated with low residual level of pesticides. In vitro and in vivo studies have also shown that pesticides cause free radical-mediated tissue damage in brain. Propolis has antioxidant properties. The main chemical classes found in propolis are flavonoids and phenolics. Bioflavonoids are antioxidant molecules that play important roles in scavenging free radicals, which are produced in neurodegenerative diseases and aging.

To determine the protective role of propolis, rainbow trouts were treated with cypermethrin, followed by biochemical analyses of brain tissue. Fish were divided into four groups: control, propolis-treated, cypermethrin-treated, and cypermethrin + propolis-treated.

In fish brains, catalase (CAT) activity decreased (P ≤ 0.001) and malondialdehyde (MDA) level increased (P ≤ 0.001) in cypermethrin-treated group compared to control group. In cypermethrin + propolis-treated group CAT activity increased (P ≤ 0.001) and MDA level decreased (P ≤ 0.001) compared to cypermethrin group.

The results demonstrated that the negative effects, observed as a result of cypermethrin treatment, could be reversed by adding supplementary propolis. Propolis may improve some biochemical markers associated with oxidative stress in fish brain, after exposure to cypermethrin.