[Limb ischemic preconditioning decreases hippocampal ischemia/reperfusion injuries in rats]

To explore the effects of limb ischemic preconditioning (LIP) on cerebral ischemia/reperfusion injuries.

Thirty six wistar rats, of which bilateral vertebral arteries were occluded permanently, were randomly divided into the following 6 groups: control group, cerebral ischemic group, limb ischemic group, LIP 0 d group (cerebral ischemia was given immediately after LIP), LIP 1 d group (cerebral ischemia was given 1 d after LIP) and LIP 2 d group (cerebral ischemia was given 2 d after LIP). Global cerebral ischemia was performed by four vessels occlusion in rats. LIP was performed by occluding the bilateral femoral arteries for 10 min 3 times in a interval of 10 min. The histological grade and pyramidal neuronal density in the CA1 hippocampus were measured to quantitate the degree of hippocampal injury under thionin staining.

The histological grade was increased and the pyramidal neuronal density was decreased in the CA1 hippocampus of the cerebral ischemic group (P < 0.01). The damage of the CA1 hippocampus in LIP 0 d group was significantly diminished, which represented by decreased histological grade and increased neuronal density compared with the cerebral ischemic group (P < 0.01). But the CA1 hippocampus still showed obvious injuries in the LIP 1 d and LIP 2 d group.

LIP performed immediately prior to cerebral ischemia could confer obvious protective effects on CA1 hippocampus against cerebral ischemia/reperfusion injuries. But LIP performed 1 d and 2 d prior to cerebral ischemia could not afford the protection against injuries induced by cerebral ischemia/reperfusion.