Effect of electroacupuncture on synaptic damage to hippocampal neurons in rats with sepsis-associated encephalopathy / 中华麻醉学杂志

ABSTRACT

Objective:To investigate the effect of electroacupuncture (EA) on synaptic damage to hippocampal neurons in rats with sepsis-associated encephalopathy (SAE).Methods:A total of 48 healthy adult male Sprague-Dawley rats, weighing 250-300 g, were divided into 4 groups ( n=12 each) using a random number table method: sham operation group (Sham group), SAE group, SAE+ EA group and SAE+ sham EA group (SAE+ SEA group). SAE was induced by cecal ligation and puncture in anesthetized rats.Baihui, Quchi and Zusanli acupoints were stimulated with constant voltage (2/15 Hz) and disperse-dense waves for 30 min once a day for 10 consecutive days, and the stimulation intensity was defined as less than 1.5 mA causing slight muscle contraction at 2 days before operation in group SAE+ EA.In group SAE+ SEA, stimulating electrodes were placed at the points 5 mm lateral to the corresponding acupoints, but no electrical stimulation was applied.On day 14 after operation, the rats were sacrificed, and hippocampal tissues were obtained and stained with haematoxylin and eosin for examination of the pathological changes in the hippocampal CA1 region, for determination of the expression of synaptophysin (SYN) and postsynaptic density protein 95 (PSD-95) (by Western blot), and for calculation of dendritic spine density of neurons in the hippocampal CA1 area (using Golgi staining) and pyramidal neurons counts. Results:Compared with Sham group, the expression of SYN and PSD-95 in hippocampus was significantly decreased, and the basal and apical dendrite spine density of neurons in hippocampal CA1 area was decreased in SAE group, the expression of PSD-95 was decreased, and the apical dendrite spine density of neurons in the hippocampal CA1 area was increased in SAE+ EA group, and the pyramidal neuron counts in the hippocampal CA1 area were reduced in SAE, SAE+ EA and SAE+ SEA groups ( P<0.05). Compared with group SAE, the expression of SYN and PSD-95 was significantly up-regulated, the basal and apical dendrite spine density of neurons in the hippocampal CA1 area was increased and the pyramidal neuron counts were increased in group SAE+ EA ( P<0.05), the pathological damage of hippocampal CA1 area was alleviated and no significant change was found in the parameters mentioned above in group SAE+ SEA ( P>0.05). Compared with group SAE+ EA, the expression of SYN and PSD-95 was down-regulated, the basal and apical dendrite spine density of neurons in the hippocampal CA1 area was decreased, and the pyramidal neuron counts were reduced in SAE+ SEA group ( P<0.05). Conclusion:The mechanism by which EA alleviates SAE may be related to reducing synaptic damage to hippocampal neurons in rats.