GAIT-STANCE DURATION AS A MEASURE OF INJURY AND RECOVERY IN THE RAT SCIATIC-NERVE MODEL

The rat sciatic nerve is a well-established animal model for the study of peripheral nerve crush injury. Footprint analysis is the most wide ly used non-invasive method of measuring functional recovery after inj ury in this model. However, this method has significant limitations du e to inability to obtain clear reproducible prints, especially when th e injury is severe, and variation of these prints with gait velocity. In the case of contracture or toe loss, footprint analysis is unreliab le. We describe a new technique, gait-stance duration, which is capabl e of non-invasively quantitating functional recovery in the rat model. This method is not dependent on accurate foot positioning during gait . It utilizes video recording of the animal walking and measures the t ime each hind foot is in contact with the floor by counting the number of frames that pass. By pairing consecutive steps, it minimizes varia tion due to changes in velocity and, by calculating a ratio of injured /uninjured hind feet, comparisons to normal gait can be made. This met hod shows recovery patterns similar to footprint analysis with small i nter-animal variability. We believe it has significant advantages over footprint analysis for the measurement of functional recovery in the crushed sciatic nerve rat model.