The effects of Tendoflex® (polytendon complex) and Hypericum perforatum (St. John’s wort oil) on repaired Achilles tendon healing in rats

Objectives: This experimental study aims to examine the effects of Tendoflex® and Hypericum perforatum on tendon healing in rat models undergoing iatrogenic Achilles tendon rupture and similar surgical treatments. Materials and methods: Eighty Wistar albino rats weighing 250 to 350 g were randomly divided into four groups. Group A: Tendoflex® was administered orally as 1 capsule/2.5 kg daily by gavage. Group B: Hypericum perforatum was administered orally as 300 mg/kg daily by gavage. Group C: Tendoflex and Hypericum perforatum were co-administered orally by gavage at the prespecified doses. Group D: No medication was given to the control group. Five rats from each group were sacrificed weekly, and the tissue samples were examined histologically, followed by the biomechanical tests of the Achilles tendon. Results: In the mechanical testing, pulling forces were superior in all intervention groups and in all weeks over the control group. In particular, in the early periods (Weeks 1, 2, and 3), the mixed group showed the most favorable results, followed by the Hypericum perforatum group (p=0.010, p=0.591, and p=0.130, respectively). The most favorable collagen type I and type III expression values were found in the mixed and Hypericum perforatum groups at Weeks 2 and 3, respectively (p=0.025 and p=0.018). In the immunohistochemical and Western Blot examinations, extreme collagen type I and type III expression were detected in the mixed and Hypericum perforatum groups at Weeks 2, 3, and 4. Conclusion: Tensile strength of the Achilles tendon increased by using Hypericum perforatum and Tendoflex following rupture and repair of the Achilles tendon in rats. The combined use of these two agents yielded the most favorable mechanical and histological results, particularly in the early period. This result may be related to the higher level of collagen type I and type III immunity in all groups, compared to the control group.