砂ネズミ海馬CA1 sector遅発性神経細胞壊死における経時的局所脳血流量変化とhemodilutionの効果に関する研究

Abstract

Regional cerebral blood flow (RCBF as a percent of control) in gerbil hippocampus CA1 sector was measured by Laser Doppler flowmetry prior to, during, and serially after 3 or 5 minute occlusion of the bilateral carotid arteries. Regional CBF was also measured in groups of 5 minute ischemia after hemodilution. In three groups, delayed neuronal death (DND) was evaluated. Hemodilution was performed to exchange human albumin for gerbil blood, after which the values of hematocrit decreased by about 26%. Sequential change of RCBF could be continuously evaluated as a definite pattern. It was clarified that constant residual blood flow at the occlusion (nil) is noted, and ischemic injury is prescribed by only ischemic time in this model, and difference of the post-ischemic hypoperfusion finally resulted. The longer the ischemic time (the larger the ischemic injury), the stronger the degree of the hypoperfusion becomes, and DND occurred strongly. It was suggested that ischemic injury in this experimental animal model was caused finally by twice ischemiae, and post-ischemic hypoperfusion is related to the cause of DND. Post-ischemic hypoperfusion could be relieved by appropriate reduction of the hematocrit by hemodilution, and that DND could be also somewhat inhibited. As its mechanisms, it was estimated that hemodilution improves cerebral microcirculation, and relieves the secodary ischemia after ischemia, and accelerates the recovery from disturbance of cerebral blood flow and metabolism.