Insulin-Like Growth Factor I Accelerates Functional Recovery from Achilles Tendon Injury in a Rat Model*

We studied the effects of insulin-like growth factor I on Achilles tendon healing in a rat model. Rats were ran-domized into groups of six each: sham surgery, tran-section alone, and transection plus growth factor. Post-operatively, rats treated with growth factor had a significantly smaller maximum functional deficit and a decreased time to functional recovery than rats in the untreated groups. Biomechanical testing revealed no significant differences in the measured parameters be-tween the treated and the untreated groups after tran-section. To study the mechanism of action, six addi-tional animals received an Achilles tendon injection of the inflammatory agent carrageenan alone and six re-ceived carrageenan plus growth factor. Rats treate