Abstract
Introduction
Obesity is one of risk factors of anterior cruciate ligament tear in man or cranial cruciate ligament (CCL) tear in dog. Adipokines are biologically active mediators released from adipocytes, and correlate with changes in body mass index. In order to study the possibility that adipocytes play a role in the pathogenesis of CCL disease, we investigated alterations of the matrix degradation biomarker genes (matrix metalloproteinase-13 [MMP-13], aggrecan) in CCL cells after stimulating with adipokines.
Materials and Methods
We collected CCLs from 6 dog cadavers that had been euthanased for reasons other than musculoskeletal disease. CCL cells were isolated and treated with key adipokines including of adiponectin, leptin and visfatin at different concentration (0.1 ng/mL, 1 ng/mL and 10 ng/mL), and at three different time points (1 h, 6 h and 24 h). Real-time PCR was used to determine gene expression for MMP-13 and aggrecan in CCL cells comparing with negative control. In addition, lipopolysaccharide was used as a positive control. The statistical significance of differences between groups was determined using non-parametric Friedman test, followed by the Conover post-hoc test, and data were considered statistically significant at P<0.05.
Results
We observed a significant difference for MMP-13 gene expression when stimulated with lipopolysaccharide at different concentrations and different time points (P<0.001 and P=0.007, respectively). However, there was no difference for any of the other treatments.
Discussion
The adipokines studied do not affect gene expression within CCL cells for MMP-13 at doses under 10 ng/mL. Further studies could involve more animals, different adipokine concentrations, other biomarkers, and also detection of matrix degradation products in cell culture media.
