The therapeutic advancements are limited for tendinopathy even though it is a common and might lead to disability. Collagenase injury model has been used for tendinopathy model. However, most of studies did not describe the precise protocols. We established proper injection volume and technique for collagenase-induced tendinopathy model.

We injected type I collagenase to Achilles tendon of Eight-week old male Sprague–Dawley rats. We compared gross morphology and histologic findings according to injection volume, concentration, and injection technique.

Injection of 62.5 units/10uL for each strip of two Achilles tendon strips, total 125 unit demonstrated homogeneous and adequate tendon injury. The homogeneity of tendinopathy was not improved with injection of>125 unit. More than 10uL injection or blind injection without skin incision was not appropriate due to profuse leakage of injection materials. Injection of both strip in Achilles tendon made more homogeneous tendon damage than injection of one strip.

The injection with 10uL of 62.5UI collagenase type I for each strips of rat Achilles tendon under direct vision is effective way to make tendinopathy animal model. These precise techniques will be helpful in research fields of tendon injury and regenerative medicine.