Electroacupuncture Alleviates Postoperative Cognitive Dysfunction in Aged Rats by Inhibiting Hippocampal Neuroinflammation Activated via Microglia/TLRs Pathway.

Pei-Pei Feng,Gai-Mei Wang,Pu Deng,Li-Hua Liu,Qi Ai,Zhe Liu,Jie Yin

doi:10.1155/2017/6421260

Abstract

Neuroinflammation has been suggested to be involved in the pathogenesis of postoperative cognitive dysfunction (POCD). Electroacupuncture (EA) is an irreplaceable method in traditional Chinese medicine that is used for treating neurodegenerative diseases in clinical and experimental studies. The aim of this study was to examine whether EA improves cognitive dysfunction caused by surgery and to investigate the pathological mechanism of TLR2 and TLR4 in the hippocampus of aged rats. A rat model of POCD was established and treated with EA or minocycline. Both EA- and minocycline-treated rats performed significantly better than untreated operated rats in spatial memory tasks of the Morris water maze (MWM) test, spending comparatively greater amounts of time in the target zone during the probe test. Additionally, decreased levels of proinflammatory cytokines (IL-1β, IL-6, TNF-α, and HMGB1) and decreased TLR2 and TLR4 protein expression in the hippocampus of EA- and minocycline-treated rats were detected. Our data suggested that EA treatment alleviated the cognition performance deficit and neuroinflammation in aged rats following surgery, which may be mediated by inhibiting the expression of hippocampal neuroinflammatory cytokines through the microglia/TLR2/4 pathway.

Highlights

Cognitive impairment after anesthesia and surgery (postoperative cognitive dysfunction (POCD)) is a recognized clinical phenomenon that was first described in older persons following surgery by Bedford in the Lancet in 1955 [1]
POCD is a common complication that refers to a decline in cognitive function following surgery, which is characterized by an impairment of memory, concentration and comprehension, and a decreased ability to process information [2, 3]
Analysis of the time in the target zone (Figure 1(c)) during the spatial probe test of rats in the operation groups revealed a significant impairment compared to the control group (P < 0.01), which was observed on postoperative day 3 (P < 0.01) and day 7 (P < 0.01)

Summary

Introduction

Cognitive impairment after anesthesia and surgery (postoperative cognitive dysfunction (POCD)) is a recognized clinical phenomenon that was first described in older persons following surgery by Bedford in the Lancet in 1955 [1]. POCD is a common complication that refers to a decline in cognitive function following surgery, which is characterized by an impairment of memory, concentration and comprehension, and a decreased ability to process information [2, 3]. It is associated with significant morbidity and mortality in elderly patients and adversely affects quality of life and social dependence [4]. Anesthetics and surgical trauma lead to neuroinflammation and cognitive dysfunction by upregulating the release of proinflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin- (IL-) 1β, and IL-6, and by activating microglia in the hippocampus [13, 14].

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