| Summary: | 碩士 === 國立成功大學 === 細胞生物及解剖學研究所 === 100 === Achilles tendinopathy is caused by excessive use or loading of physical force of the tendon and it is commonly occurred among athletes. The patient is in general treated conservatively. Radiofrequency (RF) has been proven to be an effective method to relieve pain in those patients. Currently, the pathophysiology of tendinopathy is thought to be associated with a failed healing response. In this study, collagenolytic agent was injected to the Achilles tendon to generate tendinopathy in Sprague-Dawley (SD) rat. The effects of RF, specifically, on changes of pain-related neuropeptides release and gait behavior in acutely post RF treated SD rats were examined. Collagenase І (0.3mg/20ul) or Phosphate-Buffer Saline (PBS) was injected to the rat Achilles tendon as the experiment and sham control groups. SD rats underwent skin incision over the Achilles tendon were served as normal control. The experiment was following a time-course schedule to exam post collagenase I injection on 1,3,5,7,9,11,13,15 days to examine pathohistology and gait changes. RF treatment was on day 8 after collagenase injection. Substance P, Calcitonin gene related peptide(CGRP) and Galanin expressions were examined by immunohistochemical (IHC) staining to evaluate nociception. β III tubulin immunofluorescence (IF) staining was used to evaluated nerve fiber change. Masson trichrome staining of tendon was used to examine collagen change. The gait parameters recorded and analyzed in this study included gait pattern time (stance phase, double stance phase, walk speed), distance (step length, step width, stride length, print length, intermediary toe-spread), and range of motion (initial contact, mid‐stance, pre‐swing, mid‐swing, foot angle). Substance P and CGRP IHC staining showed that the nociception was increased on the days 1, 3, 5, 7, but Substance P (n=5, p〈0.001) and CGRP (n=5, p〈0.001) decrease after RF treatment. Galanin IHC staining showed that there was no significance change in rats underwent RF treatment. β III tubulin IF staining showed that the nerve fiber density and diameter increased on the days 1, 3, 5, 7 when compared to the normal controls. However, the nerve fibers diameter (n=5, p〈0.001) were decreased after RF treatment. Masson trichrome staining showed that the tension increased after chemical injury. In post-RF treated groups, the stance phase (n=7, p〈0.05), step length (n=8, p〈0.05), intermediary toe-spread (n=8, p〈0.01) and pre‐swing (n=8, p〈0.05), were significantly different from shame and normal controls. These changes suggest that RF treatment improves gait behavior in acute tendinopathy, which allows rat ambulate toward to the normal gait pattern. Nociception is different in different time intervals, which may cause differences in gait pattern. RF treatment decreases nociception neuropeptides release, decrease nerve fiber diameter in injured Achilles tendon, improves pain and makes rat walk better. In conclusion, this study provides the first detailed analysis of RF effects on acute Achilles tendinopathy in rat. Whether these data would apply to the patients with pain in early stage of Achilles tendinopathy might require further evaluation.
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