Determination of the antioxidant and healing effects of linalool in experimental achilles tendon damage

Objective: This study was conducted to determine the antioxidant and healing effects of linalool at different doses in Achilles tendon injuries. Material and Methods: According to the study protocol, a total of 24 Wistar Albino rats were obtained from the Experimental Animals Laboratory of Adnan Menderes University Faculty of Medicine and divided into 4 groups with 6 rats each. The first group served as the control group (Control: CN), where no intervention was performed on the animals. The remaining 18 Wistar Albino rats in the other groups underwent a short-term anesthesia (90 mg/kg Ketamine + 10 mg/kg xylazine, intraperitoneal) followed by the creation of a tendon injury model by clamping the left Achilles tendons at the 3rd level of the dental clamp for 2 minutes, followed by 1 minute of release, repeated 5 times. The second group (LIN 0) received no injection. The third group (LIN 100) received daily linalool administration at a dose of 100 mg/kg, and the fourth group (LIN 200) received daily linalool administration at a dose of 200 mg/kg, both administered intraperitoneally. At the end of one week, all rats were sacrificed, and their tissues were collected for biochemical and histopathological analysis. Results: As a result of the Achilles tendon injury induced by clamping, in the injury group, levels of MDA, MPO, TNF-α, IL-1 beta, and IL-6 increased compared to the control group, while enzyme activities such as SOD, CAT, and GPx decreased. Application of linalool resulted in decreased oxidative stress values and increased activities of antioxidant defense system components (SOD, CAT, GPx). Additionally, enzyme activities in the LIN 200 group showed an increase compared to the LIN 100 group. Histopathological findings revealed that collagen fiber arrangement became irregular in the injury group, whereas it was more organized in the LIN groups. Increased inflammation, vascularity, and fibroblastic activity observed in the injury group were reduced with linalool application, with the maximum reduction seen in the LIN 200 group. Conclusion: Our findings suggest that linalool application promotes healing in Achilles tendon injury by increasing antioxidant system activities, thereby accelerating recovery. Furthermore, results indicate that the effects of linalool vary depending on the dosage, with the LIN 200 group showing significant differences compared to the LIN 100 group, highlighting the greater efficacy of a daily dose of 200 mg/kg linalool.