Properly assembled elastic fibers play an important role in providing skin with the properties of elasticity and resilience to allow for considerable mobility, but the mechanisms involved in elastic fiber assembly remains unknown. Fibulin-5 is an extracellular 66kDa glycoprotein synthesized and secreted by fibroblasts in skin, and has the ability to bind to tropoelastin. This study addresses (1) the role of fibulin-5 in the ultrastructure of elastic fibers in skin, and (2) its function in the cutaneous mechanical properties by using wild type and fibulin-5 null mice. In the first part, skin of fibulin-5 null mice as well as wild type mice was investigated in order to gain insight into the function of fibulin-5 in elastic fiber assembly. Using light and electron microscopy, the dramatic defects of dermal elastic fibers in the absence of fibulin-5 were analyzed. Interestingly, in the immunoelectron microscopy for LOXL-1, an enzyme responsible for the elastin cross-links, fibulin-5 null mouse skin exhibited similar immunoreactivity for LOXL-1 to wild type skin. Moreover, in the wild type skin, fibulin-5 localized to the microfibril-elastin interface at the edges and within the elastic fiber. In the second part of this study, the function of fibulin-5 in skin biomechanics was studied in order to determine its role in skin strength and elasticity. By using tensile tests, fibulin-5 null mouse skin was found to be significantly stiffer and weaker than wild type skin. Taken together, the defective elastic fibers in the absence of fibulin-5 suggest that fibulin-5 is involved in a secondary step of cutaneous elastic fiber assembly and in the mechanical properties of adult mouse skin.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.81611 |
| Date | January 2005 |
| Creators | Choi, Jiwon, 1977- |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Anatomy and Cell Biology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 002207881, proquestno: AAIMR12414, Theses scanned by UMI/ProQuest. |
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