七氟醚对老龄大鼠海马CA3区突触结构的影响

Effects of sevoflurane on the synaptic interface structure in hippocampal CA3 area in senile rats

目的 观察七氟醚对老龄大鼠海马CA3区突触结构的影响.方法 健康SD大鼠60 只,18 月龄,随机分为4组：空白对照组（C组）、3%七氟醚组（S1 组）、1.5%七氟醚组（S2 组）、3%异氟醚组（Ⅰ组）,每组15只.于麻醉结束后1、3、7 d （ T1 -T3 ）行Morris水迷宫实验,并测定海马CA3区突触结构各指标.结果 与C组比较,Ⅰ组T1 -T3、S1 组T1 -T2 时逃避潜伏期延长,穿越原平台象限次数减少,Ⅰ组、S1 组T1 -T3 海马CA3区突触间隙增宽,PSD厚度变薄,突触活性区长度缩短,突触界面曲率减小（ P 〈0.05 ）;与 Ⅰ 组、S1 组比较,S2 组T1 -T2时逃避潜伏期缩短,T1 -T3 海马CA3区突触间隙变窄,PSD厚度增厚,突触活性区长度延长,突触界面曲率增大（P〈0.05）;与I组比较,S1 组、S2 组T3 时逃避潜伏期缩短,穿越原平台象限次数增加（P〈0.05）;与S1 组比较,I组T3 时逃避潜伏期延长,穿越原平台象限次数减少（P〈0.05）;与T1 比较,Ⅰ组、S1 组、S2 组T2 -T3 时逃避潜伏期缩短（P〈0.05）.结论 低浓度七氟醚对老龄大鼠认知功能无明显影响,高浓度七氟醚、异氟醚均可导致老龄大鼠认知功能减退,其机制可能与抑制海马CA3区突触结构的改变有关.

Objective To observe the effects of sevoflurane on the synaptic interface structure in hippocampal CA3 area in senile rats.Methods Sixty healthy SD rats aged 18 months were randomly divided into 4 groups：blank control group（group C,n=15）,3% sevoflurance group （group S1,n=15）,1.5% sevoflurance group （group S2,n=15）,3% isoflurane group （group Ⅰ,n=15）.The Morris water maze test was performed at the 1st,3rd and 7th day （ T1 -T3 ） after anesthesia,and the synaptic structure in hippocampal CA3 area was measured.Results Compared with group C,the escape latency was longer,the frequency of crossing the original platform was reduced at T1 -T3 in group Ⅰ and at T1 -T2 in group S1,the width of synaptic cleft increased,the thickness of the postsynaptic density de-creased,the length of active zones was shortened,and the curvature of the synaptic interface decreased at T1 -T3 in group Ⅰ and group S1（P〈0.05）;Compared with group Ⅰ and group S1,the escape latency was shortened at T1 -T2 in group S2,the width of synaptic cleft decreased,the thickness of the postsynaptic density increased,the length of active zones was prolonged,and the curvature of the synaptic interface was increased at T1 -T3 in group S2（P〈0.05）;Com-pared with group Ⅰ,the escape latency was shortened,the frequency of crossing the original platform increased at T3 in group S1 and group S2（P〈0.05）;Compared with group S1,the escape latency was longer,the frequency of crossing the original platform was reduced at T3 in group Ⅰ （P〈0.05）;Compared with T1,the escape latency was shortened at T2 -T3 in group Ⅰ,group S1 and group S2（P〈0.05）.Conclusion Sevoflurane of low concentration has no obvious effect on cognitive function in senile rats.Both sevoflurane and isoflurane of high concentration can induce the cogni-tive hypofunction in senile rats,and the mechanism may be associated with the inhibition of the changes of synaptic structure in hippocampal CA3 area.