Measurement of cerebral microvessel diameters after embolic stroke in rat using quantitative laser scanning confocal microscopy

doi:10.1016/S0006-8993(00)02543-9

Brain Research

Volume 876, Issues 1–2, 8 September 2000, Pages 31-36

https://doi.org/10.1016/S0006-8993(00)02543-9 Get rights and content

Abstract

Perfusion of the microcirculation after stroke is central to preserving neuronal function and improving functional outcome. Using laser scanning confocal microscopy (LSCM) and a novel computer software program, MIRAGE, we measured a reduction in cerebral microvessel diameter after 1 and 4 h of embolic middle cerebral artery (MCA) occlusion. The methodology used by MIRAGE for measurement of blood vessel diameter involves a linearly applied spherical inflation technique. Three-dimensional quantitative analysis revealed a significant (P<0.05) mean 10–12% reduction in vessel diameter in the ipsilateral cortex when compared to the homologous region in the contralateral hemisphere. This reduction was seen only in the cortex and not the striatum. A larger reduction in mean vessel diameter in the ipsilateral cortex, 16–30% (P<0.05) was observed when compared to sham control rats. These results are in strong agreement with other studies using different stroke models and imaging techniques. Our work represents a novel application of LSCM technology to the three dimensional investigation of microvessel diameter changes in acute stroke and identifies its potential as an important tool for investigation of cerebral pathology.

Introduction

Laser scanning confocal microscopy (LSCM) technology has been used to measure plasma perfusion and to quantify expression of glial fibrillary acidic protein (GFAP), microtubule associated protein-2 (MAP-2) and fibrin in experimental ischemic stroke [14], [20], [25]. LSCM has the advantage of quantitating with great accuracy the structural relationships of the microcirculation to cells and the pathological cellular alterations of the ischemic brain.

The progression of reversible ischemic injury to irreversible necrosis after occlusion of the middle cerebral artery (MCA) can be partly attributed to persistent reduced perfusion of the microcirculation. For example, Zhang et al., using LSCM demonstrated in a rat model of embolic stroke showed progressive intravascular fibrin deposition in the microcirculation blocking perfusion in the ischemic area of the brain [22]. Maintaining perfusion in the microcirculation surrounding the core infarction may preserve neuronal tissue and improve functional outcome [3], [8]. Perfusion of the microcirculation depends on many physical parameters, such as, perfusion pressure, vessel length, plasma viscosity, shear stress and vessel diameter [10], [12]. Investigating the fundamental changes in these physical properties of the microcirculation under normal and ischemic conditions will aid in the quest to develop therapies that have a potential to improve functional outcome.

In this study, we hypothesized that under ischemic conditions, microvascular diameter is reduced. We developed a computer software program that permitted direct three-dimensional calculation of a microvessel diameters from LSCM images of cerebral tissue. Using our rat model of embolic stroke and this novel computer software program to measure vessel diameters, we report the observation that the microvasculature diameter in the cortical penumbral tissue is reduced early after stroke.

Section snippets

Material and Methods

All experimental procedures have been approved by the Care of Experimental Animals Committee of Henry Ford Health System.

Results

Table 1 describes the mean microvessel diameter of both the ischemic and corresponding contralateral hemisphere for each group. Vessel diameters were measured in both 1-h and 4-h groups. Vessel diameters were collected in the boundary area of ischemia including both the cortex and the striatum. Mean values±S.D. are listed for each time group and location. A significant reduction in the vessel diameter was seen in both the 1- and 4-h groups, but only in the cortex and not striatum. Table 2

Discussion

Patency of the microcirculation in ischemic areas of the brain after stroke is vital to reducing progressive neuronal death and improving functional outcome. Use of the LSCM to study the microcirculation allows accurate calculation of cerebral percent perfusion volume while preserving the structural and functional relationships of the microcirculation to pathologic alterations of the ischemic brain [14], [25] For instance, this laboratory has demonstrated progressive intravascular fibrin

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Research reportMeasurement of cerebral microvessel diameters after embolic stroke in rat using quantitative laser scanning confocal microscopy

Abstract

Introduction

Section snippets

Material and Methods

Results

Discussion

Brain Res.

Microvasc. Res.

Exp. Neurol.

Brain Res. Protoc.

Brain Res.

J. Neurol. Sci.

Brain Res.

Perspectives in platelet-activating factor research

Pharmacol. Rev.

Microvascular changes during cerebral ischemia and reperfusion

Cerebrovasc. Brain Metab. Rev.

Polymorphonuclear leukocytes capillaries following middle cerebral artery occlusion and reperfusion in baboons

Stroke

Innervation and effects of dilatory neuropeptides on cerebral vessels. New aspects

Blood Vessels

Research report
Measurement of cerebral microvessel diameters after embolic stroke in rat using quantitative laser scanning confocal microscopy