Objective: The effects of locally injected BAPN-f on healing of experimental injuries of the gastrocnemius tendon (GT) were evaluated.

Materials and Methods: Six mix breed large dogs free of lameness were used. Under general anaesthesia injury by zig-zag splitting was created in the GT. Ten days after injury, intra-tendinous treatment was started using BAPN-f (0.9 mg/ml) for one and saline for the opposite limb, every other day for five successive days. Sixty days after last injection dogs were euthanized and samples were taken for histological examination. The experimental protocol had been approved by the Ferdowsi University Ethical committee. All histophatological findings were graded on a scale 0 to 3. Statistical analysis was performed using the non-parameteric Sign test, significancy level was at p<0.05.

Results: The BAPN-f treated group had better organized , fibrovascular infiltration and immature fibrous tissue and inflammatory cells were significantly lower in BAPN-f group. Undulating collagen bundle was significantly higher in BAPN-f treated dogs p<0.05.

Conclusion: All tendons tended to have the same rate of healing during the 60 days of the study. The BAPN-f group tended to provide the greatest percentage of healing. Therefore, intralesional injection of BAPN-f can significantly improve healing in this model of tendonitis.