Exploration of the mechanism of ligustilide in alleviating ischemic brain injury based on mitochondrial energy metabolism

As the "power factory" of cells, mitochondria are important organelles for maintaining cellular homeostasis. The depletion of glucose and oxygen causes mitochondrial damage when ischemic stroke occurs, leading to energy metabolism disorders, reactive oxygen species (ROS) aggregation, which further aggravates ischemic nerve injury. Therefore, the aim of this study is to establish a rat middle cerebral artery occlusion/reperfusion (MCAO/R) model in vivo to investigate whether LIG can reduce ischemic nerve injury by restoring energy metabolism and the mechanism. The animal experiment protocol was approved by the Experimental Animal Ethics Committee of Anhui University of Chinese Medicine before implementation (animal ethics number: AHUCM-rats-2021030). TTC staining, neurological function score and brain index were used to evaluate nerve injury in MCAO/R rats. The levels of ROS, mitochondrial membrane potential, ATP, lactic acid and mitochondrial respiratory chain enzyme complex Ⅰ-Ⅳ were detected. The expression of glucose transporter 4 (GLUT 4) was detected by Western blot. Ligustilide was used for molecular docking with AMPK. Western blot was used to detect the protein expression levels of adenosine 5'-monophosphate (AMP)-activated protein kinase AMPK, p-AMPK, and peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) in HT22 cells damaged by oxygen-glucose deprivation/reoxygenation (OGD/R). The results showed that LIG treatment significantly reduced cerebral infarct volume, brain index and neurobehavioral score in MCAO/R rats. It inhibited the aggregation of ROS, increased mitochondrial membrane potential and ATP content, and reduced lactic acid production. Molecular docking showed that LIG had a good binding ability with AMPK. In addition, LIG increased the protein expression of p-AMPK, AMPK and PGC-1α in HT22 cells damaged by OGD/R. These results suggest that LIG alleviates ischemic brain injury by improving mitochondrial function and restoring energy metabolism, and the mechanism may be related to the activation of AMPK/PGC-1α signaling pathway.