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

To explore the effects of remote ischemic preconditioning (RIPC) on cerebral ischemia/reperfusion (I/R) injury.

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.

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).

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.