The effect of chitosan and therapeutic ultrasound treatment of achilles tendon healing in rats: Functional and Histological study

Objective: It is necessary to ensure that the damaged tendon is fully healed and to improve its functionality. We have planned our study to investigate the time-dependent effect of chitosan and therapeutic ultrasound on healing of Achilles tendon damage. It is aimed to determine the most effective treatment method by comparing tendon healing and process in different groups at different time intervals. Method: Wistar albino, Rattus norvegicus adult male rats (250-270 g) were divided into 5 groups (n = 156).Group I: Control (n = 12) No operation was performed. Group II: Damage (n = 36): Right Achilles tendons of the subjects were surgically cut from the midline to prevent damage and were planted with Kessler method. Group III: Chitosan (n = 36): Chitosan solution was applied by Kessler method. Group IV: Ultrasound (n = 36): Therapeutic ultrasound was performed after the Kessler method (1 watt / cm2 at 1 Mhz frequency for 5 minutes per week). Group V: Ultrasound + Chitosan (n = 36): After the Kessler method, both chitosan solution and therapeutic ultrasound were applied (1 watt / cm2 with 1 Mhz frequency for 5 minutes per week for 5 minutes). The effects of tenascin-C and type 3 collagen expression were investigated. Results: Among all the groups treated, we observed collagen fibers in the morphology closest to the control group in both the ultrasound and chitosan group for 6 weeks. The increase in the number of tenocytes with echromatic structure of the nucleus was supported by the findings that the collagen fibers with irregular structure were more regular, more numerous in number and their surroundings were much smoother. Conclusion: After obtaining functional and histological evaluations of all groups, both chitosan and therapeutic ultrasound methods were found to be more effective by considering the tendon healing process. Key words: Achilles tendon, chitosan, therapeutic ultrasound, collagen