Development and Application of Magnetic Resonance Imaging Techniques for the Study of Exercise-Induced Angiogenesis in the Rat Brain

In this study we show that chronic exercise leads to alterations in hemodynamic variables in the rat motor cerebral cortex. To accomplish this, we have performed functional imaging experiments in groups of rats allowed either to exercise or remain inactive for a thirty-day period. We have looked at changes in the local deoxyhemoglobin concentrations using T2*-weighted imaging, changes in blood flow, and changes in blood volume occurring as a result of this period of exercise. Based on these experiments, we have found that exercised animals have a greater concentration of deoxyhemoglobin within the motor cortex than control animals. At baseline conditions blood flow is similar for both groups but in animals that have exercised, a greater blood volume is found within the motor cortex. Taken together, these results are consistent with a greater density of capillaries within the motor cortex of exercised animals, the additional vessels being perfused with blood (both plasma and RBCs). In addition, we can conclude from these results that the linear velocity of flowing blood within the motor cortical capillaries of animals that have exercised is slower at baseline conditions than in control animals. Under hypercapnic conditions we have found that both blood flow and volume are increased in exercised animals relative to controls. This is consistent with a larger cerebrovascular reserve in the animals that have exercised as would be expected with a more dense capillary bed. In addition to reporting these results we have proposed novel techniques for both blood flow and volume imaging that can be used for future studies of this kind.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biophysics and Computational Biology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Harris, Andrew Burthe

Contributors dc:contributor

• Lauterbur, Paul C.

• Biology, Animal Physiology

Language dc:language

eng

Identifier

(MiAaPQ)AAI9953038

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/85494