Department of Anesthesiology, Zunyi Medical College, Zunyi, Guizhou, China, People's Republic.
PLoS One. 2013 May 30;8(5):e64820. doi: 10.1371/journal.pone.0064820. Print 2013.
Postoperative cognitive impairment is a common complication after cardiac and major non-cardiac surgery in the elderly, but its causes and mechanisms remain unclear. The purpose of the current study was to use resting-state functional magnetic resonance imaging (fMRI) to explore changes in the functional connectivity, i.e. the synchronization of low frequency fluctuation (LFF), in an animal model of cognitive impairment in aged rats.
Aged (22 months) rats were anaesthetized with 40 µg/kg fentanyl and 500 µg/kg droperidol (intraperitoneal) for splenectomy. Cognitive function was assessed using Y maze prior to operation and on postoperative days 1, 3 and 9. To evaluate functional connectivity, resting-state fMRI data were acquired using a 3T MR imaging system with a 4 channel phase array rat head coil.
Cognitive function was impaired at postoperative days 1 and 3 compared with preoperative. Significant synchronized LFF was detected bilaterally in the primary somatosensory cortex and hippocampus preoperatively. By contrast, no significant LFF synchronization was detected in the right primary somatosensory cortex and right hippocampus on postoperative days 1 and 3, although the pattern of functional connectivity had become almost normal by day 9.
Splenectomy performed under neuroleptic anaesthesia triggers a cognitive decline that is associated with altered spontaneous neuronal activity in the cortex and hippocampus.
术后认知障碍是老年人心血管和非心脏大手术后的常见并发症，但其病因和机制尚不清楚。本研究旨在使用静息态功能磁共振成像（fMRI）来探讨认知障碍老年大鼠动物模型中低频波动（LFF）功能连接（即同步性）的变化。
用 40μg/kg 芬太尼和 500μg/kg 氟哌利多（腹腔内）麻醉 22 个月大的老年大鼠进行脾切除术。在手术前和术后第 1、3、9 天使用 Y 迷宫评估认知功能。为了评估功能连接，使用带有 4 通道相控阵大鼠头部线圈的 3T MR 成像系统采集静息态 fMRI 数据。
与术前相比，术后第 1 和第 3 天认知功能受损。术前双侧初级体感皮层和海马区检测到明显的 LFF 同步。相比之下，术后第 1 和第 3 天右侧初级体感皮层和右侧海马区未检测到明显的 LFF 同步，尽管到第 9 天功能连接模式已基本恢复正常。
在神经安定麻醉下进行的脾切除术可引发认知下降，这与皮质和海马区自发性神经元活动的改变有关。
