Ginsenoside Rb1 alleviates cerebral ischaemia/reperfusion injury by suppressing oxidative stress and excessive autophagy via ATM-CHK2-Beclin 1 pathway.

Recent studies have demonstrated that ginsenoside Rb1 (GRb1) exhibits neuroprotective effects against cerebral ischaemia/reperfusion (I/R) injury. However, whether GRb1 modulates autophagy and oxidative stress induced by cerebral I/R remains unclear. This study aims to determine whether GRb1 attenuates cerebral I/R injury by suppressing autophagy and oxidative stress via regulation of the ATM-CHK2-Beclin 1 pathway. Middle cerebral artery occlusion/reperfusion (MCAO/R) in 60 SPF C57BL/6 mice and oxygen-glucose deprivation/reperfusion (OGD/R) in rat pheochromocytoma (PC12) cells were employed to evaluate the protective effects of GRb1 on neurological injury, autophagy, and oxidative stress. Molecular mechanisms were validated using Western blot, immunofluorescence, and pharmacological inhibitors. The results showed that GRb1 alleviated neurological impairments, decreased cerebral infarct volume, and reduced histological damage in MCAO/R mice. Besides, GRb1 alleviated cell injury and reduced intracellular ROS production in PC12 cells induced by OGD/R. Furthermore, during MCAO/R and OGD/R, GRb1 suppressed autophagy and oxidative stress. Moreover, GRb1 treatment also decreased p-ATM/ATM and p-CHK2/CHK2 ratio and increased Beclin 1-Bcl-2 interaction both in vivo and in vitro. Molecular docking further elucidated that the mechanism by which GRb1 improves cerebral ischaemia maybe related to its direct binding to ATM, which in turn inhibited the phosphorylation of ATM. Additionally, the drug affinity response target stability (DARTS) and cellular thermal shift assay (CETSA) were also performed to suggest that GRb1 directly interacts with ATM. Collectively, these findings demonstrated that GRb1 reduced ischemic stroke-induced oxidative stress and autophagy through ATM-CHK2-Beclin 1 pathway, and GRb1 may be a protective medication for the treatment of cerebral ischaemia.