A Novel Intravital Method to Evaluate Cerebral Vasospasm in Rat Models of Subarachnoid Hemorrhage: A Study with Synchrotron Radiation Angiography

Abstract

Precise in vivo evaluation of cerebral vasospasm caused by subarachnoid hemorrhage has remained a critical but unsolved issue in experimental small animal models. In this study, we used synchrotron radiation angiography to study the vasospasm of anterior circulation arteries in two subarachnoid hemorrhage models in rats. Synchrotron radiation angiography, laser Doppler flowmetry-cerebral blood flow measurement, [125I]N-isopropyl-p-iodoamphetamine cerebral blood flow measurement and terminal examinations were applied to evaluate the changes of anterior circulation arteries in two subarachnoid hemorrhage models made by blood injection into cisterna magna and prechiasmatic cistern. Using synchrotron radiation angiography technique, we detected cerebral vasospasm in subarachnoid hemorrhage rats compared to the controls (p<0.05). We also identified two interesting findings: 1) both middle cerebral artery and anterior cerebral artery shrunk the most at day 3 after subarachnoid hemorrhage; 2) the diameter of anterior cerebral artery in the prechiasmatic cistern injection group was smaller than that in the cisterna magna injection group (p<0.05), but not for middle cerebral artery. We concluded that synchrotron radiation angiography provided a novel technique, which could directly evaluate cerebral vasospasm in small animal experimental subarachnoid hemorrhage models. The courses of vasospasm in these two injection models are similar; however, the model produced by prechiasmatic cistern injection is more suitable for study of anterior circulation vasospasm.

Scaling of cerebral blood perfusion in primates and marsupials

“…On theoretical grounds, other analyses independently predict an exponent of −0.375 for shear stress scaling in mammalian aortas, but indicate that this value is not necessarily universal for all arteries (Weinberg and Ethier, 2007). We estimated the scaling of shear stress for the internal carotid artery from measured data from 70 kg humans (this study) and 375 g rats (Cai et al, 2012) using the shear stress equation and literature values. Blood flow rate in one internal carotid artery is taken as 3.83 cm 3 s −1 in humans (Boysen et al, 1970) and 0.028 cm 3 s −1 in rats (mean of four studies: Nakao et al, 2001;Ohno et al, 1979;Sakurada et al, 1978;Takagi et al, 1987).…”

“…Blood flow rate in one internal carotid artery is taken as 3.83 cm 3 s −1 in humans (Boysen et al, 1970) and 0.028 cm 3 s −1 in rats (mean of four studies: Nakao et al, 2001;Ohno et al, 1979;Sakurada et al, 1978;Takagi et al, 1987). ICA lumen radius is taken as 0.221 cm in humans (mean of three studies: Kane et al, 1996;Krejza et al, 2006;Porsche et al, 2002) and 0.0304 in rats (Cai et al, 2012). Blood viscosity is considered invariant at 0.04 dyne s cm −1 (SchmidSchönbein et al, 1969).…”

Cerebral Artery Remodeling in Rodent Models of Subarachnoid Hemorrhage

“…4). The 3-day time point was based on available data regarding the development of vasospasm [1,23,24,25]. Subsequently, animals were sacrificed and vessels were harvested.…”

“…Previous rodent studies showed that this model mimics SAH [16], including the induction of cerebral vasospasm [23,37]. This model is considered to be relatively well developed and is broadly accepted.…”

Analysis of the microvascular morphology and hemodynamics of breast cancer in mice using SPring-8 synchrotron radiation microangiography

“…In particular, it provides an important means of assessing blood flow dynamics in tumors. With appropriate consideration of radiation exposure, it is now possible to observe alterations in vascular morphology and intratumoral micro-hemodynamics during tumor progression sequentially over time Cai, Sun et al, 2012). Further studies are needed to develop new markers of abnormal tumor microvessels.…”