Objective assessment of tendon histomorphology, particularly in the context of tissue repair, requires comprehensive analyses of both cellular distribution and matrix architecture. Fourier Transform analyses of histological images collected with second harmonic generation (SHG-FT) technique provide objective, quantitative assessment of collagen fiber organization with high specificity. Concurrent nuclear staining allows simultaneous analyses of cell morphology and distribution. Tendon injuries can be career-limiting in human and equine athletes, since the architectural organization of the tissues are lost in the course of fibrotic repair. Objective assessment of tendon repair is problematical, particularly in research addressing potential therapies. Fourier Transform analyses of histological images collected with second harmonic generation (SHG-FT) technique can provide objective, quantitative assessments of collagen fiber organization with high specificity. This study describes the use of SHG-FT with fluorescently-labelled tendon-derived cells (TDC) in an in-vivo model of equine tendinitis to assess the temporal and spatial effects of cell delivery on collagen fiber organization.Summary
Introduction
Corticosteroids (CS) are commonly administered by intra-articular injection to control the symptoms of osteoarthritis; however, CSs also suppress articular chondrocyte matrix synthesis. Both triamcinolone and methylprednisolone acetate significantly suppressed BMPs −2 and −7, and TGF-b1 expression, suggesting a mechanism by which CSs suppress articular chondrocyte matrix synthesis and cartilage homeostasis. Osteoarthritis (OA) is a common and debilitating disease that affects approximately 30% of the US population and is also a major clinical problem in companion animals. There are many drugs available to manage the symptoms of OA. Of these, intra-articular corticosteroid (CS) administration is a common and very effective anti-arthritic therapy, and is frequently administered to equine athletes. CSs exert their potent anti-inflammatory effects by blocking phospholipase A and reducing inflammatory mediator production; however, CSs also suppress matrix-biosynthetic activity of articular chondrocytes. This activity, along with ther increased joint use that symptomatic relief allows, has been linked to ‘steroid arthropathy’; a progression of arthritis driven by compromised chondrocyte homeostatic capacity. Several lines of experimental and clinical evidence emphasise the importance of TGF-b and BMP autocrine/paracrine activity in maintaining the homeostatic status of articular chondrocytes (reviewed in Oshin and Stewart 2007). This study was carried out to address the following objectives: 1) To assess the effects of CS on expression of chondro-protective TGF-β and BMP ligands in equine articular chondrocytes, and 2) To determine if exogenous BMP ligand administration can mitigate the suppressive effects of CSs on articular chondrocyte synthesis of collagen type II (Coll II) and glycosaminoglycans (sGAG).Summary
Introduction
