Changes in Cellular and Biomechanical Properties in the Rat Gastrocnemius Muscle Complex Following Injection of Platelet Rich Plasma and TraumeelRTMS Post Calcaneal Tenotomy

The aim of this thesis was to design a rat calcaneal tenotomy model that could be used to investigate the effect of PRP and TraumeelRTMS on the microscopic and biochemical properties of healing tendon and muscle. For the first study, the rat calcaneal tenotomy model was developed to determine baseline values for the natural progression of repair tension over six weeks following tenotomy, as well as the concurrent changes in myofibre diameter, percentage of total collagen, transforming growth factor-beta (TGF-beta1) and basic-fibroblast growth factor (b-FGF) protein expression in the gastrocnemius-calcaneal tendon unit and developing neotendon. For the second study, the calcaneal tenotomy model was used to investigate the effect of post-tenotomy injections of PRP and/or TraumeelRTMS. Repair tension was measured in vivo using a Shimpo force gauge. Histological analysis included measurement of myofibre diameter with bright field microscopy, and percentage/thickness of collagen with polarizing microscopy. Western blot analysis was used to study the time course of TGF-beta1 and b-FGF protein expression. The results of this study indicate that predominantly PRP but also TraumeelRTMS can: (1) decrease mean repair tension at four and six weeks post tenotomy; (2) increase myofibre regeneration, measured by an earlier return to normal myofibre diameter; (3) stimulate neotendon regeneration, measured by an increase in the mean percentage of collagen and percentage of thick collagen fibres, and (4) increase TGF-beta1 and b-FGF protein expression within the gastrocnemius muscle and neotendon. Since TGF-beta1 and b-FGF play important stimulatory roles in tendon and muscle healing, this increase in growth factor expression within the muscle and neotendon following injection may have stimulated faster myofibre and neotendon regeneration. The tenotomy model and injection protocol developed in this thesis, and most importantly the results of this thesis, can be used as a foundation for future basic science and subsequent clinical studies.