Relationship between long-tern presence of hypoxic tissue and astrocyte activation after cerebral infarction in rats / 中华神经医学杂志

ABSTRACT

Objective To explore the relationship between the long-term presence of hypoxic tissue and astrocyte activation after cerebral infarction in rats. Methods Middle cerebral artery occlusion was performed in rats to induce permanent brain ischemia (PI group) or transient isehemia for 1.5 h followed by reperfusion (1.5 h IR group). Double immunofluorescence staining with EF5 and gliai fibrillary acidic protein (GFAP) antibodies was used to observe the hypoxic tissue and status of astrocyte activation, respectively. On days 1, 3, 7 and 14 after the operation, GFAP fluorescence intensity and the presence of hypoxic tissue in the ischemic cortex were observed. Results The hypoxic tissues were present from day 3 to day 14 after the operation in 1.5 h IR group, but disappeared after day 3 in PI group. GFAP fluorescence intensity in the hypoxic tissue was significantly higher than that in the surrounding tissues at all the observation time points (P<0.05). GFAP fluorescence intensity increased progressive in both groups with the lapse of time (P<0.05), reaching the peak level on day 7 followed then by gradual declination. On each of the time points for observation, GFAP fluorescence intensity in 1.5 h IR group was significantly higher than that in PI group (P<0.05). Conclusion Astrocyte activation is especially obvious in the hypoxic brain tissues after cerebral infarction, which is closely associated with the long-term existence of hypoxic tissues.