The timeline of metalloprotease events during oligofructose induced equine laminitis development
Article first published online: 23 JUN 2011
© 2011 EVJ Ltd
Equine Veterinary Journal
Volume 44, Issue 1, pages 88–93, January 2012
How to Cite
VISSER, M. B. and POLLITT, C. C. (2012), The timeline of metalloprotease events during oligofructose induced equine laminitis development. Equine Veterinary Journal, 44: 88–93. doi: 10.1111/j.2042-3306.2011.00393.x
- Issue published online: 1 DEC 2011
- Article first published online: 23 JUN 2011
- [Paper received for publication 07.12.10; Accepted 04.03.11]
- matrix metalloprotease;
Reason for performing study: The role of matrix metalloproteases (MMPs) and the timeline of proteolysis during laminitis development are incompletely understood.
Objectives: To determine the temporal progression of selected MMPs and protease regulators during laminitis development.
Methods: Five clinically normal Standardbred horses received, via nasogastric intubation, an oligofructose (OF) bolus (10 g/kg bwt). Laminitis induction proceeded for 48 h followed by euthanasia. Lamellar biopsies were obtained prior to dosing and at intervals during the treatment period for analysis (12, 18, 24, 30 and 36 h and at 48 h following euthanasia). Tissue samples were analysed by real-time PCR, zymography and western blotting.
Results: Activation of proMMP-2 occurs either simultaneously or at least 12 h following lamellar basement membrane (BM) damage, while no activation of proMMP-9 is seen during OF laminitis induction. Aggrecanase gene expression increased initially at 12–18 h post OF dosing, similar to BM changes. Gene expression of TIMP-2, a MMP regulator, decreases during laminitis development.
Conclusions: The MMP-2/MT1-MMP complex may not play a major role in initiating lamellar BM damage. Aggrecanase and TIMP-2 gene expression appear related to BM lamellar changes.
Potential relevance: MMPs, historically thought to cause laminitis, do not appear to play an initiating role in the lamellar lesion. Other host derived proteases and degradation of alternative lamellar matrix components need to be considered.