Scutellarin ameliorates mitochondrial dysfunction and apoptosis in OGD/R-insulted HT22 cells through mitophagy induction

Scutellarin (Scu), a flavonoid from herbal Erigeron breviscapus (Vaniot) Hand-Mazz, exerts neuroprotective effects against cerebral ischemia. However, whether the effects of Scu are related to mitochondrial protection needs further investigation. In this study, we aimed to clarify the mechanisms of Scu against HT22 cells injury caused by oxygen-glucose deprivation and reperfusion (OGD/R). Our results proved that Scu significantly reduced the overload of intracellular reactive oxygen species (cellar ROS) and mitochondria reactive oxygen species (mito-ROS), ameliorating oxidative stress damage. TUNEL positive rate, Caspase-3 activity, and Cytochrome c (Cyto-c) expression remarkably decreased following Scu treatment. Meanwhile, Scu could maintain mitochondrial morphology and reverse ultrastructure changes. And mitochondrial membrane potential (MMP), oxygen consumption rate (OCR), adenosine triphosphate (ATP) production and Na⁺/K⁺-ATPase activity were obviously promoted. Additionally, Scu was found to stimulate mitophagy level by increasing the expression of LC3, Beclin1, PINK1 and Parkin proteins, as well as promoting the degradation of p62. More importantly, the regulatory effects of Scu on mito-ROS, MMP, ATP, Na⁺/K⁺-ATPase, cell viability and lactate dehydrogenase (LDH) were markedly limited by Mdivi-1 (a mitophagy inhibitor). Of note, the inhibitor also reversed Scu-mediated apoptosis suppression, evidenced by the diminished apoptosis rate, the down-regulated expression activities of Cyto-c, Bax and cleaved Caspase-3, as well as the elevated level of Bcl-2 protein. Collectively, Scu could improve mitochondrial dysfunction and inhibit apoptosis by stimulating mitophagy, thereby attenuating OGD/R-induced HT22 cells injury.