棕榈油对大鼠局灶性脑缺血再灌注损伤保护作用的实验研究

The experimental research of the protective effect of palm oil on focal cerebral ischemia/reperfusion injury in rats

目的研究棕榈油(palm oil,PO)对大鼠局灶性脑缺血再灌注后梗死体积及细胞凋亡相关基因Bcl-2和Bax蛋白表达的影响,探讨棕榈油的脑缺血保护作用及机制。方法用线栓法建立大鼠大脑中动脉缺血再灌注损伤模型。将健康雄性SD大鼠随机分成4组:空白对照组、假手术组、缺血再灌注组(IR)、PO处理组。空白对照组与假手术组每组12只大鼠,缺血再灌注组与PO处理组再分为再灌注2 h、6 h、12 h、24 h、72 h、7 d等6个亚组,每亚组12只大鼠。TTC染色观察脑缺血再灌注损伤后的损伤体积;SDS聚丙烯酰胺凝胶转移电泳(westernblotting,WB)检测Bcl-2、Bax的表达水平并观察PO的保护作用。结果①TTC染色:空白对照组与假手术组未见缺血失染区域,缺血再灌注组与棕榈油处理组缺血再灌注后2h均未见明显的缺血失染区,在缺血再灌注6 h、12 h、24 h、72 h、7 d各时间点,PO处理组梗死质量百分比与对应的IR组数值比较均有统计学差异(P<0.05),PO处理组较缺血再灌注组缺血梗死脑区质量百分比减少;②WB:缺血再灌注组及棕榈油组从再灌注6 h开始Bcl-2、Bax在半暗带区表达增强,随缺血时间延长,表达呈先升高后降低,Bcl-2于缺血12 h达高峰,Bax于缺血24 h达高峰。各时间点PO处理组与相应缺血组相比,Bcl-2的表达量显著增加(P<0.05),Bax的表达量显著减少(P<0.05)。结论①棕榈油可以减小大鼠局灶性脑缺血再灌注后的缺血受损范围;②棕榈油能够增加大鼠局灶性脑缺血再灌注后凋亡抑制基因Bcl-2表达作用,降低凋亡基因Bax表达作用,保护神经细胞。

Objective To investigate the effect of palm oil（PO） on the volume of the infarction,the expression of Bcl-2 and Bax protein following focal cerebral ischemia/reperfusion in rats,and explore the protective effect of PO on focal cerebral ischemia/reperfusion and the underlying mechanism.Methods The acute focal cerebral ischemia/reperfusion models were established with suture emboli.Healthy male Sprague-Dawley rats were randomly divided into four groups： normal control group,sham group,IR group and PO group.There were 12 rats in each of the normal control group and the sham group.The IR group and PO group were further subdivided into subgroups and sacrificed 2 h,6 h,12 h,24 h,72 h and 7 d after ischemia/reperfusion（n=12）.The volume of the infarction was observed by the TTC method;and the expression of Bcl-2 and Bax was determined by Western blotting to observe the protective effect of PO.Results ① TTC staining： there was no region of ischemia/reperfusion injury in the normal control group and the sham group.There was no region of ischemia/reperfusion injury in IR group and PO group 2 h after ischemia/reperfusion.At the time points of 6 h,12 h,24 h,72 h and 7 d after ischemia/reperfusion,there were statistical differences in mass percentage of the infracted regions between the PO group and the IR group（P0.05）,and mass percentage of the infracted cerebral regions in the PO group was reduced as compared to the IR group.② Western-blotting： From the time point of 6h after reperfusion,in both PO group and IR group,the expression of Bcl-2 and Bax increased with time in the ischemia penumbra with peak expression at 12 h,and then decreased.The expression of Bax reached the peak at 24 h,and then decreased.Western-blotting analysis showed a gradual increase in Bcl-2 expression（P0.05） and a gradual decrease in Bax expression（P0.05） in PO group at each time point（6 h,12 h,24 h and 72 h after ischemia/reperfusion）,compared with IR group.Conclusions ① PO can reduce the region of ischemia injury following focal cerebral ischemia/reperfusion injury;② PO can protect nerve cells by increasing the expression of Bcl-2 and decreasing the expression of Bax,following the cerebral ischemia/reperfusion injury.