Cranial cruciate ligament disease and rupture (CCLD/ R) is a common orthopaedic condition in dogs. CCLD/ R can be due to trauma (least common) or to non-contact injury (most common). Once the cranial cruciate ligament (CCL) is damaged complications such as stifle osteoarthritis can occur. Different dog breeds are at an altered risk to CCLD/ R. Previous biochemical and ultrastructural studies have found that glycosaminoglycans (GAGs) were altered in high risk dog breeds when compared to CCLs from a dog breed at low risk of ligament rupture. We hypothesise that proteoglycans and GAGs may vary between different anatomical regions of the CCL, and between differentially predisposed dog breeds to CCLD/ R. Proteoglycans were determined by semi-quantitative Western blotting, quantitative RT-PCR (qRT-PCR), quantitative biochemistry, semi-objective histology scoring, and immunohistochemistry. Water and GAG content in the CCLs was also measured. Further qRT-PCR analysis was conducted to determine the expression of ECM proteases (ADAMTS -4 & -5) in the canine CCL. We showed with Western blot analysis that certain proteoglycans and GAGs were significantly different between anatomical regions of Staffordshire bull terrier CCLs. Data analysis between differentially predisposed dog breeds showed that the Staffordshire bull terrier CCLs (a moderate-high risk dog breed to CCLD/ R) had a significant increase in water content compared to greyhound CCLs (a low risk dog breed to CCLD/ R). Further, gene expression and Western blot analysis of fibromodulin, gene expression of aggrecan, and Western blot analysis of chondroitin-6 sulphate stubs were significantly increased in Staffordshire bull terrier CCLs compared to greyhounds. Decorin and ADAMTS-4 gene expression were significantly increased in greyhounds compared to Staffordshire bull terrier CCLs. Histology analysis showed that fibrocartilaginous regions were present in the CCL and were mainly observed in predisposed dog breeds to CCLD/ R. Furthermore, immunohistochemistry analysis showed that each proteoglycan had a different distribution throughout the CCL, which indicates that proteoglycans provide essential functionality to the CCL. The increase of certain proteoglycans and GAGs in CCLs of Staffordshire bull terriers might indicate increased fibrocartilage regions as a result of compressive loads. These changes in ECM content in the Staffordshire bull terrier indicate higher loading pressure on the CCL and could compromise the tissue, leading to increased incidence of disease and rupture. The increase of decorin in greyhounds could be essential for maintaining collagen fibril strength, whilst the increase of ADAMTS-4 could indicate a higher rate of turnover to regulate normal CCL homeostasis.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:706868 |
| Date | January 2016 |
| Creators | Allaith, S. M. |
| Publisher | University of Liverpool |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://livrepository.liverpool.ac.uk/3003228/ |
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