Neuroprotective effects of chlorogenic acid by controlling the Bcl-2 family protein in a stroke animal model.

Abstract

Ischemic stroke causes severe brain damage and high mortality. Chlorogenic acid is a phenolic compound that has neuroprotective properties. B-cell lymphoma-2 (Bcl-2) family proteins are important for apoptosis regulation. Bcl-2 and Bcl-xL are proteins that inhibit apoptosis, and Bax and Bad induce apoptosis. In this study, we investigated whether chlorogenic acid exerts a neuroprotective effect against ischemic stroke damage by regulating Bcl-2 family proteins. We performed middle cerebral artery occlusion (MCAO) to induce ischemic stroke in adult male rats. The animals were intraperitoneally injected with normal saline as a vehicle or chlorogenic acid (30 mg/kg) 2 hr after MCAO. Cerebral cortex tissue was collected 24 hr after MCAO damage. MCAO damage caused histopathological changes and increased the number of terminal deoxynucleotidyl transferase deoxyuridine triphosphate (dUTP) nick end labeling-positive cells, while chlorogenic acid attenuated these changes. RT-qPCR and Western blot results showed decreases in Bcl-2 and Bcl-xL expression and an increase in Bax and Bad expression in MCAO animals. However, chlorogenic acid treatment attenuated these changes due to MCAO damage. The interaction of Bax with Bcl-2 or Bcl-xL decreased in MCAO animals, and the binding of Bad with Bcl-2 or Bcl-xL increased. However, chlorogenic acid treatment reduced these changes. Chlorogenic acid also prevented MCAO-induced increases in caspase-3 and caspase-9 expression. This study provides evidence that chlorogenic acid has neuroprotective effects against MCAO damage by modulating Bcl-2 family proteins including Bcl-2, Bcl-xL, Bax, and Bad. Furthermore, chlorogenic acid regulates the interaction between Bcl-2 family proteins. In conclusion, chlorogenic acid contributes to neuroprotection against ischemic stroke damage by controlling Bcl-2 family proteins.