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

AIM: To explore the effects of limb ischemic preconditioning (LIP) on cerebral ischemia/reperfusion injuries. METHODS: 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. RESULTS: 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. CONCLUSION: 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.