Preoperative vitamin-rich carbohydrate loading alleviates postoperative cognitive dysfunction in aged rats

With the acceleration of an aging population, postoperative cognitive dysfunction (POCD) has become a large problem. Preoperative carbohydrate (CHO) loading has been reported to attenuate surgery stress response and insulin resistance. The present study aimed to investigate whether preoperative vitamin-rich CHO loading has an effect on POCD, endoplasmic reticulum (ER) stress, and apoptosis. Eighty male Sprague-Dawley rats (20-month old) were randomly assigned to four groups (20 per group): control group (no anesthesia and surgery), fasting group (fasting 14 h before surgery), water group (oral water 3 h before surgery), and CHO group (oral vitamin-rich CHO 3 h before surgery). The POCD rat model was established by splenectomy under intraperitoneal injection of pentobarbital sodium. Cognitive function was assessed using the Morris water maze (MWM) after surgery. The levels of endoplasmic reticulum (ER) stress markers and apoptosis related proteins in the hippocampus were examined by western blot analysis. The vitamin-rich CHO treated animals performed better in the MWM tests than the animals in the fasting and water groups. Furthermore, preoperative CHO loading reduced ER stress and neuronal apoptosis in the hippocampus of aged rats, as indicated by the protein biomarkers of GRP78, eIF2a, Beclin1, Bax, and Bcl-2. In conclusion, preoperative vitamin-rich CHO loading could improve POCD by attenuating ER stress and neural apoptosis, providing a basis as a potential treatment against POCD.