Novel experimental model to integrate study of biomechanics and microvascular physiology in vivo

Abstract

Living systems experience and regulate mechanical forces (i.e., stresses) in their environment at the cellular, tissue, and organ level. Critical processes such as the regulation of tissue fluid balance, wound healing, and angiogenesis are governed in part by the mechanical interaction of the microvasculature and its surrounding tissues. Study of the functional and structural adaptation in response to biomechanical stimuli has suffered from the lack of an animal model free of confounding effects of anesthesia and trauma, noninvasive methods to make consecutive measurements in the same animal over a period of days and methods to introduce controlled mechanical stretch of tissue. To meet these needs, the Pallid bat wing was introduced for noninvasive characterization of microvascular function in vivo. We designed a custom device to stretch the wing without interfering with the ability to quantify microvascular variables (e.g. vessel diameter, blood flow, and shear stress). This experimental model, a combination of a novel animal model and a classic engineering method, thus allows for the characterization of functional responses of microvessels to stresses, structural adaptations of tissue and the microcirculation to an altered biomechanical environment and regulation of microvascular functions by surrounding tissues (i.e., interstitial tethering).