大脳皮質静脈うっ滞による脳梗塞と脳浮腫の進展—上矢状静脈洞閉塞による実験的検討

EVOLUTION OF VENOUS CEREBRAL INFARCTION AND BRAIN EDEMA: AN EXPERIMENTAL STUDY WITH SAGITTAL SINUS OBSTRUCTION

　抄録　Cyanoacrylate mixtureを用いて成猫上矢状静脈洞閉塞モデルを作製し閉塞120時間後までの間のEB漏出と静脈性出血性脳梗塞の経時変化につき検討した。静脈系の閉塞が静脈洞に限局しているAグループでは閉塞後120時間でもEBの漏出，組織学的変化はわずかであった。一方大脳皮質静脈系も広範に閉塞しているBグループではEB漏出，出血性脳梗塞を種々の程度に認めた。本グループは漏出EBの分布から（1）上矢状洞近傍の皮質に主に分布し，脳浮腫およびグリオーシスが主である第1群と（2）皮質下白質にも多量のEBを認め，皮質の出血性梗塞と皮質下白質の脳内血腫により閉塞6-12時間後までに深昏睡状態となる第2群に分類された。第1群における漏出EBの進展は皮髄境界を越えず皮質に留まる傾向が認められた。一方第2群ではうっ血による血管周囲小出血がまず閉塞静脈洞近傍の皮質から始まり，その後小出血の融合による脳内血腫形成が直下の皮質下白質に認められた。

Superior sagittal sius with/without neihboring venous system of 36 mongrel cats were occluded by cyanoacrylate polymer after i. v. administration of Evans-blue (EB). Thereafteter, the cats were sacrificed 1, 3, 6, 12, 24, 72 or 120 hours after sinus-vein occlusion. According to the degree of occluded region, the cats were divided into two groups ; group A (GA) and B (GB). GA showed only superior sagittal sinus occlusion, while many cortical veins were also occluded in GB. No EB nor histological changes were found in 13 cats of GA and 4 sham operated cats, while EB ditribu-tion was observed in all 20 cats of GB. The other 3 cats of GA showed a little EB in gyruslateralis. EB distribution of GB were divided into two types. Type 1 showed EB mainly in the cortical gray matter, while type 2 showed massive EB extravasation in the white matter as well. Edematus changes with gliosis in its resolution phase, were observed in type 1. In addition, EB free zone was formed along with U-fiber zone (cortico-medullary junction) in the cats of later phase (72 hours after occlusion). The findings of EB extension in the type 1 means the existence of blockage against edema evolution from cortex toward subocortical white matter. The cats of type 2 showed fulminant hemorrhagic changes which appeared depend on time interval. Although occurence of pathological changes were rather earlier than that of cases of clinical cerebral sinus thrombosis, this pathological findings demonstra-ted the typical character of venous hemorrhagic infarction. In this paper, the similarity and diffe-rence between this model and .clinical case of sinus-vein thrombosis were discussed. And the possible function of the U-fiber zone in the corti-comedullary junction aginst edema evolution was suggested.