The effect of pentoxi̇fylli̇ne in experimental achilles' tendon injured in rabbi̇ts

In our study, we aimed to investigate the effect of pentoxifylline, which has not been studied before, on tendon healing both biomechanically and histopathologically by forming an Achilles tendon injury model on rabbits. Our study was performed on 36 rabbits with experimental Achilles tendon injury in Abant Izzet Baysal University Experimental Animal Application and Research Center. 36 rabbits were divided into 2 groups as group A and group B. After tendon repair, the rabbits in group A were administered physiological saline solution (PSS) 0.5cc/kg/day and the rabbits in group B were administered pentoxifylline (PTX, Trental® ampule 100 mg, Sanofi Aventis, Istanbul, Turkey) through daily intramuscular injections. 9 rabbits randomly selected from 18 rabbits in each group were evaluated histopathologically and biomechanically at the 4th week. At the end of the 6th week, remaining 9 rabbits in group A and 9 rabbits in group B were evaluated histopathologically and biomechanically. When compared histopathologically, there was no significant difference between the groups in terms of inflammation at week 4 and week 6 (p>0.05). In terms of neovascularization, the rate of vascularization was found to be higher at both the 4th week (p=0.03) and the 6th week (p=0.004) in our study group and the difference was statistically significant. In terms of the regulation of collagen fiber arrangement, it was also found that the fiber array was more regular at the 4th week (p=0.007) and the 6th week (p =0.01) in our study group and it was statistically significant. In the evaluation of inflammation grades, there was no significant difference between the two groups at week 4 (p>0.05). However, at week 6, the control group was found to have a statistically higher level of inflammation (p=0.04). At the 4th week, the maximum displacement and maximum tear strength of the study group were higher than the control group and the difference was statistically significant. There was no statistically significant difference between the two groups in 2-mm gap formation forces (p>0.05). At the 6th week, the maximum tear strength parameter was found to be statistically higher in the control group than in the study group. In terms of the other two parameters, which are maximum displacement and 2-mm gap formation forces, there was no statistically significant difference between the groups (p>0.05). In conclusion, we think that pentoxifylline can be used in tendon healing clinically because it increases tendon healing and strength both histopathologically and biomechanically in the early period and rehabilitation can be performed more safely in early period of tendon healing through PTX administration.