Using the biomechanical model (chapter 6) we demonstrated that RGTAs are effec-tive in reducing the pull out force, i.e. neural adhesions, after nerve crush injury.Regulation of HBGF activity by RGTAs effectuates a reduction of extraneural scar for-mation, in particular regulation of TGF-beta, which promotes collagen deposition andfibrosis.The results of this study do not reveal positive or negative influence of RGTAs onaxonal regeneration as measured by magnetoneurography (chapter 3 & 4). Also, noimproved or accelerated recovery pattern of static TSF (chapter 2) was demonstratedduring the six weeks following injury. A lack of improved conduction capacity usingRGTAs may be explained by the type of injury. Following crush injury (axontmesis),axonal regeneration is complete and relatively fast compared to total transection of anerve (neurontmesis). It is possible that the positive effect of RGTAs, i.e. reduction ofintraneural fibrosis, is not relevant in this type of injury in the rat model. When severi-ty of injury is increased, for example in a nerve repair model, acceleration and improve-ment of regeneration by the use of RGTAs may be demonstrated.When comparing pull out force (POF) results of chapter 6 and chapter 7, there is nosignificant difference between crush injury control groups six weeks after crush injury.Mean POF (+ SEM) of control HA-gel study is 230.26 (+ 11.59 g) and mean POF (+SEM) of control RGTA study is 206.96 g (+ SEM 13.90). The small difference may becaused by the fact that these studies were performed by different investigators at differ-ent time points. Yet, a striking difference is noted between the antiadhesion effect of HA-gel and RGTAs. HA-gel effectuates a decrease of 29% in peak force, whereas RGTAsaccomplish a decrease of 67% in peak force after nerve crush injury. To demonstrate asignificant difference between both antiadhesion therapies both strategies should be114
Research Perspectives The general aim of this thesis was to quantify physiological and pathophysiologicalprocesses, associated with the site ofa possible nerve injury, in the rat sciatic nervemodel. Validated experimental methods providing quantifiable outcome data can pro-vide solid evidence for potential beneficial strategies to promote recovery after periph-eral nerve injury. It is not feasible to review all future possibilities in this field ofresearch. However, a few research perspectives can be summarized, which are directlyrelated to this thesis:-In future experimental studies on promotion of recovery after nerve injury, thetype ofassessment technique should carefully be considered. A quantifiablemeasure is preferred, which is directly related to the hypothesis of the experi-ment.-Experimental research using Magnetoneurography requires an investment intechnical knowledge. The financial aspects of the recording set up are compara-ble to other conventional neurophysiological methods. When deciding to per-form neurophysiological measurements as an assessment method, ex vivo meas-urements are preferable over conventional electrophysiology.