Background: Some studies have showed that hypothermia is a neuroprotective factor for cerebral ischemic injury. Inflammation reaction plays a very important role in pathomechanism of neuron degeneration disease induced by cerebral ischemia. However whether there is relationship between cold irritation and inflammation reaction is not well known.
Objective: To explore effect of cold irritation on peripheral white blood cell and ICAM-1, IL-1β expression of brain tissue in rat with cerebral ischemia.
Methods: Model rats were put into low temperature water (0º) for cold irritation for 5 minutes one time every day for 20 days. MCAO rats were subjected to middle cerebral artery occlusion (MCAO) using an intraluminal suture method with permanent ligation of the ipsilateral common carotid artery. We assessed count of the peripheral white blood cells.The brains of all rats were cut at 1, 3, and 5 days after cerebral ischemia and frozen brain tissues were continuously sliced and stained immunohistochemically with Intercellular Adhesion Molecule-1 (ICAM-1) or Interleukin-1(IL-1) antibody.
Results: Cold irritation model rats were associated with increased leukocyte at 1 and 3 days post-ischemia, increased ICAM-1-positive vessels at 1, 3, and 5 days, and increased interleukin-1(IL-1) at 3 and 5 days. Vascular pathology of the hippocampus at electron microscope levels showed that the blood vessel has inflammation infiltration at 1, 3 and 5 days. Conclusion: These data demonstrate that cold irritation significantly increased endothelial adhesion molecule expression, leukocyte infiltration, and vascular pathology of the hippocampus in rat. The mechanism of neuron injury may be related to the inflammation reaction induced by cold irritation.
