大鼠脑缺血再灌注后细胞内钙与凋亡的关系及米帕明的保护作用

Relationship between Intra-neuronal Ca^(2+) Content and Neuron Apoptosis and the Protective Effects of Imipramine in Rats Given Brain Ischemia-Reperfusion

目的观察大鼠脑缺血再灌注后细胞内钙与凋亡的关系及米帕明(Imipramine,Imi)的保护作用和可能机制。方法本实验采用线栓法建立大鼠局灶性脑缺血-再灌注损伤模型。将48只健康Wistar大鼠随机分成3组:假处理组(A组)、缺血-再灌注模型组(B组)和缺血-再灌注+Imi组(C组),每组16只。给药方法:C组缺血前60min腹腔注射Imi20mg/kg,A组、B组腹腔注射等容积9%氯化钠溶液。每组大鼠8只行细胞凋亡检查,8只测细胞内游离Ca2+。结果A、B两组脑中游离Ca2+间差异有统计学意义(P<0·01);B、C组脑中游离Ca2+间差异有统计学意义(P<0·01);假手术组可见少量原位末端转移酶标记(TUNEL)阳性细胞,B、C组脑中TUNEL阳性细胞与A组间差异有统计学意义(P<0·01),C组脑中TUNEL阳性细胞与B组间差异有统计学意义(P<0·01)。结论Imi对脑缺血-再灌注损伤的保护作用可能与抑制细胞内的Ca2+超载,降低脑缺血后神经元的凋亡,减轻脑缺血损伤有关。

Objective To explore Intraneuronal Ca^2＋ content and neuron apoptosis, and to study the protective effects of imipramine （Imi） in rats given brain ischemia - reperfusion. Methods The rat models with focal cerebral ischemia - reperfusion were established to make middle cerebral artery occlusion （MCAO） by method of reversibly inserting a nylon thread. In this study, 48 healthy Wistar rats were randomly divided into three groups： a sham operation group （Group A）, a cerebral ischemia- reperfusion group （Group B） and a cerebral ischemia- reperfusion and imipramine group （Group C ）. Group C were given intraperitoneally 20 mg/kg of Imi 60 minutes before MCAO establishment, and Group A and Group B were given the same volume of sodium chloride solution. In each group, the contents of free Ca^2＋ were determined in eight rats and the apoptosis of neurons in another eight rats. Results Group A was significantly different from Group B and Group C in free Ca^2＋ contents （ P 〈0. 01 ）; Significant difference was found in free Ca^2＋ between Group C and Group B （ P 〈 0. 01 ）; Some positive cells of transferase -mediated deoxyuridine triphosphatebiotin nick end labelling （TUNEL） were seen in Group A, and Group A was significantly different from Group B and Group C in positive cells of TUNEL （ P 〈0. 01 ）, and there was significant difference in positive cells of TUNEL between Group B and Group C （ P 〈 0.01 ）. Conclusion 1. This study demonstrates that Imi has protective effects on cerebral ischemia - reperfusion lesion. 2. The possible protective mechanism of Imi might be related with overload of Ca^2＋ in suppressor, decrease of apoptotic neurons and abatement of cerebral ischemia injury.