缺血再灌注不同时间点大鼠海马细胞内Ca~(2+)含量比较

目的研究脑缺血再灌注损伤中大鼠海马神经细胞内Ca~(2+)含量的变化,检测环磷腺苷葡胺(MAC)预处理对其的影响。方法将SD大鼠60只按实验分为正常组(5只)、假手术组(5只)、缺血再灌注组(再灌注组)和MAC预处理组(预处理组)。再灌注组和预处理组又分为再灌注后2、24、48、72 h和7天5个时间点,每个时间点5只大鼠,线栓法建立大鼠局灶性脑缺血再灌注损伤模型,流式细胞仪检测缺血侧海马神经细胞内Ca~(2+)的含量,观察MAC预处理对细胞内Ca~(2+)含量变化的影响。结果与假手术组比较,再灌注组2 h细胞内Ca~(2+)含量开始增高,24、48 h Ca~(2+)含量达到高峰(P0.01),72 h Ca~(2+)含量开始下降,7天Ca~(2+)含量进一步降低,但仍高于假手术组水平;与再灌注组比较,预处理组缺血再灌注2 h Ca~(2+)含量差异无统计学意义,24、48、72 h Ca~(2+)含量显著降低(P0.01)。结论细胞内Ca~(2+)含量增高为缺血再灌注损伤的病理机制之一,MAC预处理能有效抑制细胞内Ca~(2+)含量增高,在大鼠局灶性脑缺血再灌注损伤中起到保护作用。

Comparison of free intracellular Ca2+ in hippocampus cells at different time points after focal cerebral ischemia/reperfusion in rat

Objective To study changes of free intracellular Ca~(2+) after focal cerebral ischemia/ reperfusion on rat and the effect of meglumine adenosine cyclosphosp(MAC) pretreatment on them.Methods Sixty Sprague-Dawley rats were randomly divided into four groups:normal group (5) ,sham operated group(5) ,ischemia/reperfusion group(reperfusion group) ,MAC pretreatment group(MAC group).Reperfusion group and MAC group were further divided into 5 groups at 2, 24,48,72 h and on d 7 after reperfusion,5 rats at each time point.The acute focal cerebral ischemia /reperfusion models were established with suture embolus method as described by Nagasawa. The content of free intracellular Ca~(2+) in hippocampus cells was detected by flow cytometry.Results Compared with sham operated group,in reperfusion group,the content of free intracellular Ca~(2+) of hippocampus cells began to increase at 2 h,peaked at 24,48 h (P < 0.01),began to decrease at 72 h and further decreased on d 7,however,it was still higher than normal level.Compared with reperfusion group,there was no statistically significant difference of intracellular Ca~(2+) at 2 h,but it significantly decreased at 24,48,72 h in MAC group (P<0.01).Conclusions Intracellular Ca~(2+) elevation in hippocampus cells after ischemia/reperfusion is one of pathologic mechanisms in ischemia/reperfusion injury.Pretreatment with MAC can inhibit this elevation significantly.