远程缺血预处理对大鼠局灶性脑缺血/再灌注损伤的保护作用

目的探讨远程缺血预处理(RIPC)对大鼠局灶性脑缺血/再灌注(I/R)损伤的影响。方法SD雄性大鼠70只,随机分组,每组10只。对照组仅行单纯缺血后再灌注;RIPC组按RIPC与脑缺血间隔时间不同分为30min及1、2、12、24和48h组,即反复3次夹闭双侧股动脉造成肢体缺血5min、再灌注5min后,分别间隔30min及1、2、12、24和48h后,行大脑中动脉栓塞(MCAO)120min、再灌注24h。对各组动物进行神经功能缺损评分,然后行氯化三苯四唑(TTC)染色,计算脑梗死容积。结果与对照组比较,RIPC1、2和24h组神经功能缺损评分显著下降,差异有显著性(P均<0.05);而RIPC30min、12h和48h组与对照组比较差异均无显著性(P均>0.05)。脑梗死容积百分比RIPC1h组〔(17.9±7.5)%,P=0.016〕、2h组〔(18.3±11.2)%,P=0.019〕和24h组〔(20.2±11.9)%,P=0.047〕均明显小于对照组〔(30.5±9.8)%〕;而RIPC30min、12h和48h组与对照组比较差异无显著性(P均>0.05)。结论RIPC对大鼠局灶性脑I/R损伤有保护作用,其保护时程为预处理后1～2h,24h后再次出现。

Protective effect of remote ischemic preconditioning against focal cerebral ischemia/reperfusion injury in rats

OBJECTIVE: To explore the effects of remote ischemic preconditioning (RIPC) on cerebral ischemia/reperfusion (I/R) injury. METHODS: Seventy male SD rats were randomly divided into seven groups (n=10 for each): (1) Control group: animals were subjected to I/R. (2)RIPC groups: RIPC was performed by 3 cycles of occlusion/reperfusion of bilateral femoral arteries for 5 minutes/5 minutes. According to the different intervals between RIPC and middle cerebral artery occlusion (MCAO), 6 RIPC subgroups were established: RIPC 30 minutes, 1, 2, 12, 24 and 48 hours subgroups, with intervals between RIPC and cerebral I/R of 30 minutes, 1, 2, 12, 24 and 48 hours respectively. The duration of MCAO was 120 minutes and reperfusion for 24 hours. The neurological dysfunction score (NDS) was evaluated at 24 hours after reperfusion. The infarction volume was then assessed with tetrazolium chloride (TTC) staining. RESULTS: The NDSs of RIPC 1, 2 and 24 hours groups were significantly lower than that of control group (all P<0.05), while with no significant differences of RIPC 30 minutes, 12 and 48 hours groups (all P>0.05). The area percentage of infarction in RIPC 1 hour (17.9+/-7.5)%, P=0.016], RIPC 2 hours (18.3+/-11.2)%, P=0.019] and RIPC 24 hours (20.2+/-11.9)%, P=0.047] groups was significantly smaller than that in control group (30.5+/-9.8)%], while no significant differences were observed in RIPC 30 minutes, 12 and 48 hours groups (all P>0.05). CONCLUSION: The RIPC the brain against focal cerebral I/R injury in rats, and the protection window is 1 to 2 hours after pretreatment and resumes after 24 hours.