α7 nicotinic acetylcholine receptor agonist attenuates the cerebral injury in a rat model of cardiopulmonary bypass by activating the Akt/GSK3β pathway.

Abstract

α7 nicotinic acetylcholine receptor (α7nAchR) agonist treatment may provide a promising therapeutic effect for cerebral injuries. However, it is unclear whether the activation of α7nAchR agonist may reduce cerebral injuries induced by cardiopulmonary bypass (CPB). A total of 96 male Sprague-Dawley rats were randomly divided into four groups (n=24/group): i) Sham operation group; ii) CPB group; iii) CPB + α7nAchR agonist group; and iv) CPB + α7nAchR agonist + α7nAchR antagonist group. Following treatment, 24 rats from each group were sacrificed and the serum and hippocampal tissues were collected. The serum expression levels of S100β, interleukin 6 and tumor necrosis factor α were evaluated by ELISA, hippocampal tissues were analyzed by histopathological examination using hematoxylin & eosin and terminal deoxynucleotidyl-transferase-mediated dUTP nick-end labeling (TUNEL) staining and Caspase 3 expression in the hippocampal tissues was evaluated by immunohistochemistry. In addition, Caspase 3, Akt and glycogen synthase kinase 3β (GSK3β), as well as phosphorylated (p)-Akt and (p)-GSK3β were examined by western blot assay. The present study demonstrated that α7nAchR agonist treatment was able to alleviate pathological damage and inhibit hippocampal cell apoptosis and inflammatory response. α7nAchR agonist treatment also increased the expression levels of p-Akt and p-GSK3β, which indicated an upregulation in Akt/GSK3β signaling. These data suggested that α7nAchR agonist may provide a promising new therapeutic approach for cerebral injury caused by CPB.