慢性强迫游泳抑郁模型大鼠类P300电位的变化

Changes of P300-like potential in rats of depression following repeatedly forced swim stress

目的探讨大鼠慢性强迫游泳抑郁模型类P300电位改变及其与行为变化的关系。方法将40只SD雄性大鼠均分为4组:强迫游泳7d模型组(S1组)、强迫游泳14d模型组(S2组)和2组对照组(C1组、C2组)。观察大鼠体质量、旷场实验和液体消耗实验等行为学指标。在麻醉状态下采用听觉oddball模式刺激诱发大鼠类P300电位,测定N1、N2、P3潜伏期和P3波幅。对大鼠类P300电位变化和行为学检测指标进行相关性分析。结果模型组大鼠与对照组相比体质量增长率降低(F=253.60,P<0.01),蔗糖水摄入率下降(F=128.38,P<0.01),旷场实验中水平得分(F=124.73,P<0.01)和垂直得分(F=41.09,P<0.01)减少,修饰次数(F=15.04,P<0.01)增加。与对照组比较,S1组和S2组P3潜伏期显著延长[S1组:(469.7±30.69)ms,S2组:(498.9±25.54)ms,C1组:(389.6±49.43)ms,C2组:(378.5±39.77)ms;F=71.534,P<0.01],P3波幅明显降低[S1组:(19.60±10.62)μV,S2组:(16.00±11.98)μV,C1组:(28.30±22.63)μV,C2组:(28.70±10.71)μV,F=5.187,P=0.029]。P3潜伏期和多项行为学指标呈显著负相关,而与修饰行为呈显著正相关(r=0.475,P=0.002)。P3波幅与水平得分呈显著正相关(r=0.366,P=0.020),而与修饰次数呈显著负相关(r=-0.343,P=0.030)。结论慢性强迫游泳应激诱发大鼠出现明显抑郁行为,同时抑郁模型大鼠类P300电位发生异常改变,提示抑郁模型大鼠表现情绪障碍的同时可能伴有认知功能损害。

Objective To explore whether there are abnormalities of P300-like potential in stressed rats following repeatedly forced swim stress. Methods Forty male rats were randomly divided into 4 groups, the control groups （Control-1 and Control-2 ） and the stress groups （Stress-1 and Stress-2 ）. Rats in stress groups were administered to repeatedly forced swim for 7 or 14 d respectively. Body weight gain, saccharin pre- ference test and open field test were performed. After being anesthetized with urethane, P300-1ike potential were evoked by the oddball auditory stimulation. Deviant sounds were presented in a homogenous series of standard sounds. Results Our results of behavioral tests displayed less body weights and less saccharine solution intake in stressed group rats and significant effects of stress on the number of crossing squares, the duration of rearing and the number of grooming in open field test. Prolonged P3 latencies and decreased P3 amplitudes of P3OO-like potentials were found in the stressed rats. Moreover, there were significant correlations between parameters of P300 （including P3 latency and P3 amplitude） and a serial of behavioral traits. Conclusion This study provides an important evidence of changes of P300-like potential in depressed rats following repeatedly forced swim stress. Based on this study, event related potentials should be taken into consideration and applied as the useful tools in the research work of depressed animal models.