Gardenia jasminoides Extract GJ-4 Alleviates Memory Deficiency of Vascular Dementia in Rats through PERK-Mediated Endoplasmic Reticulum Stress Pathway

Abstract

Endoplasmic reticulum stress (ERS) is involved in the pathological process of vascular dementia (VD). GJ-4 is extracted from Gardenia jasminoides J. Ellis and has been reported to have protective roles in ischemia-related brain damage. However, the role of GJ-4 in ERS has not been elucidated. We established a VD rat model through bilateral common carotid arteries occlusion (2-VO). The rats were intragastrically administrated with GJ-4 (10, 25, and 50[Formula: see text]mg/kg) and nimodipine (10[Formula: see text]mg/kg). Data from a Morris water maze test showed that GJ-4 could significantly alleviate learning and memory deficits in VD rats. Nissl and cleaved caspase-3 staining revealed that GJ-4 can inhibit apoptosis and thus exert a protective role in the brain of 2-VO rats. Western blot results suggested that GJ-4 significantly reduced ERS-related protein expression and inhibited apoptosis through suppression of the PERK/eIF2[Formula: see text]/ATF4/CHOP signaling pathway. For in vitro studies, the oxygen-glucose deprivation (OGD) SH-SY5Y model was employed. Western blot and Hoechst 33342/PI double staining were utilized to explore the effects of crocetin, the main active metabolite of GJ-4. Like GJ-4 in vivo, crocetin in vitro also decreased ERS-related protein expression and inhibited the activation of the PERK/eIF2[Formula: see text]/ATF4/CHOP signaling pathway. Thus, crocetin exerted similar protective roles on OGD challenged SH-SY5Y cells in vitro. In summary, GJ-4 and crocetin reduce the ERS in the brain of VD rats and SY5Y cells subjected to OGD and inhibit neuronal apoptosis through suppression of the PERK/eIF2[Formula: see text]/ATF4/CHOP pathway, suggesting that GJ-4 may be useful for the treatment of VD.