Microglial response to early ischemia-induced changes in the rat spinal cord

We examined the early microglial response to spinal cord ischemia induced by occlusion of the descending aorta for 15 min, or more limited aortic occlusion (8, 10, 12 min( linked with blood volume reduction. The recovery of motor function and activation of microglia labeled by Griffonia simplicifolia B4‐isolectin (GSA I‐B4‐HRP) were assessed up to 7 days post‐ischemia. Activation of resident microglia characterized by both increased lectin binding and altered morphology was observed >48 hrs post‐ischemia. Massive infiltration of the microglia/macrophages related to the severity of ischemic insult appeared at day 3. Our data suggest that (1) ischemia of different degrees gives rise to a generalized microglial response at the early post‐ischemic phase; (2) graded activation of microglia/macrophases as a response to ischemic neuronal injury occurs within 48–72 hrs of post‐ischemic reperfusion; (3) lectin labeling of microglia can serve for continuous study of the evolution of pathological changes associated with transient spinal cord ischemia.