Electroacupuncture improves cognitive impairment after subarachnoid hemorrhage in rats through the PI3K/AKT signaling pathway

Cognitive impairment (CI) is highly prevalent in subarachnoid hemorrhage (SAH) patients. The phosphatidylinositol 3-kinase (PI3K)/AKT pathway plays a critical role in neuronal survival in a variety of central nervous system injuries. This study aimed to determine whether electroacupuncture (EA) at Yintang and LI20 ameliorates SAH-CI in a rat model and to examine whether it modulates the PI3K/AKT pathway by administering a PI3K inhibitor (LY294002) versus dimethyl sulfoxide (DMSO) vehicle. Notably, 129 male Sprague-Dawley rats were divided into Blank, Sham, SAH and SAH + EA groups (Experiment 1, n = 54) and SAH, SAH + EA, SAH + LY294002, SAH + EA + LY294002 and SAH + EA + DMSO groups (Experiment 2, n = 75). Garcia scoring was used to evaluate neurological function. The moisture content of the rat brain was determined by dry‒wet method. The Morris water maze was used to assess learning and memory function. Pathological changes in neurons in the hippocampus were observed via hematoxylin-eosin (H&E) staining. The number of surviving neurons and the percentage of apoptotic cells in the hippocampus were detected via Nissl and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining. The expression of PI3K/AKT pathway-related proteins was detected via Western blotting. The results indicated that EA intervention after SAH reduced brain water content, enhanced Garcia scores, improved neurological function and behavioral markers of CI, and increased the number of surviving neurons in the hippocampus. Moreover, EA significantly increased the expression of AKT, phosphorylated (p)-AKT, PI3K, p-PI3K, glycogen synthase kinase (GSK)-3β, p-GSK-3β and B cell lymphoma (Bcl)-2 proteins, and decreased the expression of Bcl-2-associated X (Bax) and caspase-3. In addition, the effects of EA were abolished by LY294002. EA appeared to improve CI in a rat model of SAH through the activation of the PI3K/AKT pathway.