异丙酚后处理对大鼠海马氧糖缺失/复氧复糖时 CA1区神经元突触传递的影响

Effect of propofol post-conditioning on synaptic transmission in neurons in CA 1 region during oxygen-glucose deprivation and restoration in hippocampi in rats

目的：评价异丙酚后处理对大鼠海马氧糖缺失/复氧复糖（OGD/R ）时CA1区神经元突触传递的影响。方法雄性Wistar大鼠，15～20日龄，体重50～60 g ，快速断头取脑组织，制备350μm厚的海马脑片，采用随机数字表法，将其分为3组（ n＝12）：对照组（C组）置于正常人工脑脊液中培养7 min＋1 h；OGD/R组置于持续通以95％ N2的无糖人工脑脊液中孵育7 min ，然后放入正常人工脑脊液中孵育1 h；异丙酚后处理组（P组）置于持续通以95％ N2的无糖人工脑脊液中孵育7 min ，然后放入含异丙酚浓度为1.2μg/ml的人工脑脊液中孵育1 h。采用全细胞膜片钳技术记录CA1区神经元自发兴奋性突触后电流（sEPSC ）和自发抑制性突触后电流（sIPSC ）的强度和频率。结果与C组相比， OGD/R组和P组sEPSC的强度和频率升高，sIPSC的强度和频率降低（ P＜0.05）；与OGD/R组相比，P组sEPSC的强度和频率降低，sIPSC的强度和频率升高（ P＜0.05）。结论异丙酚后处理减轻大鼠海马OGD/R损伤的机制与其抑制CA1区神经元兴奋性突触传递和增强抑制性突触传递有关。

Objective To evaluate the effect of propofol post-conditioning on synaptic transmission in neurons in CA1 region during oxygen-glucose deprivation and restoration （OGD/R） in hippocampi rats .Methods Hippocampi were isolated from male Wistar rats ,aged 15-20 days ,weighing 50-60 g ,and sliced at 350μm thick . The hippocampal slices were divided into 3 groups （ n=12 each ） using a random number table ：control group （group C） ,OGD/R group ,and propofol post-conditioning group （group P） .In group C ,the hippocampal slices were cultured in normal artificial cerebro-spinal fluid （nACSF ） for 7 min ＋ 1 h . In OGD/R group , the hippocampal slices were incubated in glucose-free ACSF aerated with 95% N2 for 7 min followed by restoration of O2-glucose supply for 1 h .In group P ,the hippocampal slices were incubated in glucose-free ACSF aerated with 95% N2 for 7 min followed by incubation with normal ACSF containing propofol 1.2μg/ml for 1 h .The intensity and frequencies of spontaneous excitatory postsynaptic currents （sEPSC ） and spontaneous inhibitory postsynaptic current （sIPSC ） in neurons in CA1 region were recorded by whole-cell patch-clamp technique .Results Compared with group C ,the intensity and frequency of sEPSC were significantly increased ,while the intensity and frequency of sIPSC were decreased in OGD/R and P groups （ P〈0.05） .Compared with group OGD/R ,the intensity and frequency of sEPSC were significantly decreased ,while the intensity and frequency of sIPSC were increased in group P （ P〈0.05） .Conclusion The mechanism by which propofol post-conditioning attenuates OGD/R injury to hippocampi is related to inhibition of excitatory synaptic transmission and enhancement of inhibitory synaptic＆nbsp;transmission in neurons in CA1 region .