Loss of CO2-induced Distensibility in Cerebral Arteries with Chronic Hypertension or Vasospasm after Subarachnoid Hemorrhage Loss of CO2-induced Distensibility in Cerebral Arteries with Chronic Hypertension or Vasospasm after Subarachnoid Hemorrhage

We developed a rat cerebral angiography system using monochromatic synchrotronradiation X-rays at SPring-8, a third generation synchrotron radiation facility. Usingnew technique, we assessed the distensibility of major trunk arteries after subarachnoidhemorrhage (SAH) in normotensive and hypertensive rats. Twenty-five adult WistarKyoto rats (WKY) and fourteen stroke-prone spontaneously hypertensive rats (SHR)were prepared SAH by double hemorrhage injection method into cisterna magna.Angiography was performed on day 7 and was repeated three times in each rat beforeand after loading of hypercapnia at 100-120 mmHg of PaCO2. The diameters of majortrunk vessels were assessed. Light microscopic observation of artery lumen and wallwere also performed. Angiographical vasospasm was demonstrated in basilar artery inWKY with 66 % reduction in diameter of control. In ICA and other major trunk inWKY and all the arteries in SHR did not demonstrate vasospasm. SHA resulted in lossof hypercapnia-induced distention in BA of WKY. In SHR, the distensibility wasimpaired regardless of hemorrhage. Histological study demonstrated basilar artery inWKY thickened at 184 % after SAH and became similar to non-hemorrhagic SHR.ICA in WKY and both BA and ICA in SHR were unchanged in wall thickness beforeand after SAH. High quality angiography demonstrated deteriorated distensibility inchronic hypertension or SAH-induced spastic vessels.

We developed a rat cerebral angiography system using monochromatic synchrotronradiation X-rays at SPring-8, a third generation synchrotron radiation facility. Usingnew technique, we assessed the distensibility of major trunk arteries after subarachnoidhemorrhage (SAH) in normotensive and hypertensive rats. Twenty-five adult WistarKyoto rats (WKY) and fourteen stroke-prone spontaneously hypertensive rats (SHR)were prepared SAH by double hemorrhage injection method into cisterna magna.Angiography was performed on day 7 and was repeated three times in each rat beforeand after loading of hypercapnia at 100-120 mmHg of PaCO2. The diameters of majortrunk vessels were assessed. Light microscopic observation of artery lumen and wallwere also performed. Angiographical vasospasm was demonstrated in basilar artery inWKY with 66 % reduction in diameter of control. In ICA and other major trunk inWKY and all the arteries in SHR did not demonstrate vasospasm. SHA resulted in lossof hypercapnia-induced distention in BA of WKY. In SHR, the distensibility wasimpaired regardless of hemorrhage. Histological study demonstrated basilar artery inWKY thickened at 184 % after SAH and became similar to non-hemorrhagic SHR.ICA in WKY and both BA and ICA in SHR were unchanged in wall thickness beforeand after SAH. High quality angiography demonstrated deteriorated distensibility inchronic hypertension or SAH-induced spastic vessels.