title: Evaluation of gene expression through qRT-PCR in cyclically loaded tendons: an in vivo model.
abstract: An in vivo rabbit animal model for the tendinopathy, epicondylitis, was used to examine the effects of repetitive load on the expression of various genes associated with matrix remodeling. Following 80 h of cumulative load, tissue from the distal and proximal regions of the flexor digitorum profundus tendon was collected. Quantitative RT-PCR was used to asses mRNA levels of collagenase-1 (MMP-1), stromelysin (MMP-3), vascular endothelial growth factor (VEGF), connective tissue growth factor (CTGF), cyclooxygenase-2 (COX-2), interleukin-1beta (IL-1beta), type III collagen (COL-III) and fibronectin (FBRN). No significant differences in expression levels were found between loaded and unloaded limbs at either region of the tendon. The findings were unexpected as the same model has already demonstrated an increase in the density of cells staining for VEGF and CTGF. Different regulatory mechanisms between mRNA and protein expression or localized changes missed due to homogenization of the tissue samples, may explain the discrepancy in findings.
authors.affiliation: Joint Graduate Group in Bioengineering, University of California, Berkeley/San Francisco, CA, USA.
authors.forename: Krishna R
authors.initials: KR
authors.lastname: Asundi
authors.forename: Karen B
authors.initials: KB
authors.lastname: King
authors.forename: David M
authors.initials: DM
authors.lastname: Rempel
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics; D000818:Animals; D024061:Collagen Type III / Q000235:genetics; D055513:Connective Tissue Growth Factor; D051546:Cyclooxygenase 2 / Q000235:genetics; D005353:Fibronectins / Q000235:genetics; D005552:Forelimb / Q000503:physiopathology; D005786:Gene Expression Regulation / Q000502:physiology*; D017874:Immediate-Early Proteins / Q000235:genetics; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics; D053583:Interleukin-1beta / Q000235:genetics; D020781:Matrix Metalloproteinase 1 / Q000235:genetics; D019278:Matrix Metalloproteinase 3 / Q000235:genetics; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D012333:RNA, Messenger / Q000032:analysis*; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013314:Stress, Mechanical; D052256:Tendinopathy / Q000235:genetics; D013710:Tendons / Q000378:metabolism* / Q000473:pathology* / Q000503:physiopathology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics; D016474:Weight-Bearing / Q000502:physiology
chemical_list: D024061:Collagen Type III; D005353:Fibronectins; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D053583:Interleukin-1beta; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D055513:Connective Tissue Growth Factor; D051546:Cyclooxygenase 2; D019278:Matrix Metalloproteinase 3; D020781:Matrix Metalloproteinase 1