Protective effect of hypoxic preconditioning against cerebral ischemic injury induced by acute cerebral infarction in mice

Abstract

Objective To observe the protective effect of hypoxic preconditioning against cerebral ischemic injury induced by acute cerebral infarction in mice. Methods Blb/c mice were randomized into normal control, sham-operated, acute cerebral infarction (CI), and hypoxic preconditioning with CI (HP+CI) groups. In the latter two groups, acute cerebral cortical infarction was induced photochemically by cold light exposure of the brain tissue following intravenous Rose Bengal injection. The mice in the sham-operated group received only cold light exposure without Rose Bengal injection. Behavioral test, immunofluorescence assay and confocal laser scanning microscopy were performed to evaluate the neurological deficits of the mice and assess the cell apoptosis, and the cerebral infarction volume was measured. Results No infarct was found in the normal control and sham-operated groups, whereas obvious isehemic infarction foci were found in CI and HP+CI groups, but the infarction volume was significantly smaller in HP+CI group (P<0.05). The mice in the normal control and sham-operated groups presented with no neurological impairment, but in CI and HP+CI groups, obvious symptoms of neurological impairment were observed with lowered neurological scores. The neurological scores were significantly higher in HP+CI group than in CI group (P<0.05). Occasional apoptotic cells were found in the normal control and sham-operated groups, while in the other two groups, the TUNEL-positive cell number increased significantly. The apoptotic cell number was significantly smaller in HP+CI group than in CI group (P<0.05). Conclusion Hypoxic preconditioning may protect against cerebral ischemic injury induced by acute cerebral infarction in mice possibly by reducing the cerebral infarction volume and cell apoptosis. Key words: Hypoxic preconditioning; Acute cerebral infarction; Cell apoptosis