Abstract:
The vascular adventitia is recognized as a dynamic mediator of vascular structure
and function, yet its role in aging is not understood. The purpose of this thesis was to
examine the age-related changes of the vascular adventitia and determine the underlying
mediators responsible. Male Sprague-Dawley rats were aged to 15,30,50 and 80 weeks
before being anesthetised and euthanized by exsanguination. Thoracic aortas, mesenteric
and pudental arteries were isolated, formalin fixed, and embedded in paraffin then
sectioned at 51lm. Vessels were examined by microscopy and protein expression was
determined by indirect immunofluorescence. The thickness of the adventitia increased
dramatically with age. Immunofluorescence revealed a robust expression of endothelin
system proteins in the adventitia. Additionally, extracellular matrix proteins collagen and
fibronectin, and the proliferation marker Ki67 showed strong adventitial origin. The
changes observed in the vascular adventitia with aging clearly demonstrate an important
role in the process of vascular aging.
