Biomedical and General Engineering Department
BS in Biomedical Engineering
The study of blood vessel growth and remodeling is a complex endeavor. Hypoxia, the lack of oxygen in a tissue, is known to stimulate angiogenesis (the growth of new blood vessels), and have little effect on arteriogenesis (the enlargement of existing blood vessels). However, the role of hypoxia in vessel function is unknown, but may be determined using the results and methods developed in this experiment.
Supplied by the bloodstream, oxygen is required by all cells and tissues to remain healthy. If the bloodstream supplying a certain tissue with blood is disrupted, the tissue becomes ischemic, often leading to hypoxia. Hypoxia is the lack of oxygen in living tissue; specifically tissue oxygen levels less than 10 mmHg (hypoxyprobe.com).
When a tissue is ischemic, and therefore hypoxic, angiogenesis is known to occur, which expands the nutrient and waste exchange capacity of the microcirculation. Hypoxia-inducible factor (HIF) is a transcriptional regulator of angiogenic molecular pathways and is regulated according to the oxygen availability in a given tissue (Pugh, Ratcliffe). By studying the locality of hypoxia within a given tissue, it is possible to predict the behavior of the growing blood vessel. Additionally, changes in vessel function may be understood by comparing the location of hypoxia with the location of the altered function. Cal Poly’s microcirculation laboratory is interested in investigating the effects of hypoxia, either prior or sustained, on vascular reactivity. In order to carry out this investigation, a method for assessing the level of hypoxia throughout the tissue is needed.
In this study, immunohistochemical staining techniques were used to visually map hypoxia in ischemic mouse hindlimb skeletal muscle. The technique, which was developed into a repeatable protocol, may be useful in further investigating hypoxia induced vascular growth and changes in function.