Abstract: Transcutaneous electrical stimulation (TES) has recently been used in resolving experimentally severed superficial flexor tendon which leads to acute tendonitis. However, mechanism by which (TES) promote tendon repair is not fully understood. In this study 4 right superficial flexor tendon of hind limb of horses were subjected to daily therapeutic regimen of TES for 10 minutes for 15 days using 100 Hz frequency and 80 µs intensity ( 2.8 ± 0.6 mA) after being severed in full length thickness in total length of 10 cm in the mid- tendon area and similarly in another 4 right tendon in control horses no treatment was pplied. Tendons were subjected to ultrasonographical, histological and, tensile strength evaluation which has been reported separately for publication and hydroxyproline content for 60 days after treatment. There were remarkable differences between hyroxyproline contents of severed tendon with those of normal ones in control group, whereas there was not significant differences in treated tendons with those of normal ones in the same horses. This study suggests that using hydroxyproline content as a direct marker of the effect of TES on
collagen content in injured tendon. J.Vet.Res. 62,2:43-47,2007.