ラット脳局所虚血モデル—2．脳梗塞巣の計測と脳血流パターンの検討

FOCAL CEREBRAL INFARCTION IN THE RAT: II. NEUROPATHOLOGICAL STUDY AND LOCAL CEREBRAL BLOOD FLOW PATTERN

　抄録　ラット中大脳動脈閉塞モデルにより，閉塞1週間の梗塞巣を組織学的に検討し，梗塞率を測定した。閉塞1日，2日，5日後の脳血流パターンを¹⁴C-iodoantipyrineによるオートラディオグラムにより観察した。冠状6断面による梗塞率は，sham手術群0.59±0.46％（平均±標準偏差），閉塞群14.05±2.66％とほぼ均一な梗塞巣が認められた。オートラディオグラムによる脳血流パターンでは，梗塞部にほぼ一致した中大脳動脈領域の血流低下が認められ，大脳皮質では対側の10〜15％，尾状核頭部外側では11％に低下していた。同側淡蒼球・黒質では30〜40％の血流上昇，同側視床では50％の血流低下が認められた。この血流増加は，尾状核の梗塞に起因する錐体外路核のinhibitory outputの低下による異常興奮—代謝亢進による血流増加と推定される。

We have recently reported that middle cerebral artery (MCA) occlusion in the rat produces a uni-form pattern of cerebral ischemia in an acute phase. This study was done to determine if this model is also useful for quantitative evaluation of infarction size in a chronic phase. [Methods] Spra-gue-Dawley rats were anesthetized with halothane and left MCA was occluded via transretro-orbital approach. The following studies were done. (a) Neuropathological study was done one week after MCA occlusion. After perfusion fixation, the brain was cut into 6 coronal slices and stained sec-tions were examined. (b) Local cerebral blood flow patterns were observed by ¹⁴C-iodoantipyri-ne autoradiographic technique 1, 2, and 5 days after the occlusion. [Results] (a) Neuropathological studies invariably showed infarct in the cortex and the lateral part of the basal ganlia. The ratio of the infarct to the total areas of both hemispheres in 6 coronal sections was 14.05±2.66% (Mean±SD) in MCA occluded animals (N=14) and 0.59±0.46% in sham operated animals (N=12). (b) Relative to the contralateral hemisphere, marked reduction in CBF was seen in the territory of the MCA and moderate reductions were also seen in the surrounding areas. The same pattern of in-creased CBF as previously reported was also seen in the ipsilateral substantia nigra and globus pal-lidus 1, 2, and 5 days after the occlusion.

These results indicate the usefulness of this chronic focal cerebral infarction model in the eval-uation of infarction. (Received: October 21, 1985)