Neuroprotective effect of Angelica gigas root in a mouse model of ischemic brain injury through MAPK signaling pathway regulation

Background: The root of Angelica gigas Nakai (Apiaceae) has been traditionally used as an important herbal medicine to treat blood-deficiency-related disorders in Eastern Asian countries, and recently, it has been recognized as a potential candidate for improving cardiovascular diseases.

Methods: In this study, the neuroprotective effect of a methanol extract of A. gigas root (RAGE) was investigated in a mouse stroke model induced by a 90 min transient middle cerebral artery occlusion (tMCAO). Infarction volumes and morphological changes in brain tissues were measured using TTC, cresyl violet, and H&E staining. The neuroprotective mechanism of RAGE was elucidated through investigation of protein expression levels using western blotting, IHC, and ELISA assays. The plasma concentrations of decursin, a major compound in RAGE, were measured after oral administration of RAGE to SD rats.

Results: The infarction volumes in brain tissues were significantly reduced and the morphological deteriorations in the brain neuron cells were improved in tMCAO mice when pre-treated with RAGE at 1000 mg/(kg bw·d) for two consecutive days. The neuroprotective mechanism of RAGE was confirmed to attenuate ERK-related MAPK signaling pathways in the ipsilateral hippocampus hemisphere in mice. The concentrations of decursin in rat plasma samples showed peak absorption and elimination in vivo after oral administration of RAGE at 100 mg/rat.

Conclusion: Mice administered RAGE before the tMCAO operation had less neuronal cell death than those that were not administered RAGE prior to the operation, and this study provides preclinical evidence for use of A. gigas in ischemic stroke.

Keywords: Angelica gigas (apiaceae); Infarction; Ischemic stroke; Neuroprotection; Pharmacokinetics.