Objective. To examine the effects of polysulphated glycosaminoglycan on tendon healing in a controlled collagenase injury model. Design. The study used a completely randomized design with four horses assigned to each of two groups, control and treated. The superficial digital flexor tendons from each horse were measured weekly by ultrasound techniques. The differences between groups were evaluated using t-statistics and trends summarized by simple linear regression. Animals. Eight horses (four Thoroughbreds and four Standardbreds) with normal superficial flexor tendons were divided into two groups of four. Group #1 control horses were not treated. Group #2 horses were treated with polysulphated glycosaminoglycans. Procedure. All of the horses had tendinitis induced in the superficial flexor tendon of both forelimbs by the injection of 4000 IU of collagenase. The treated group received 500 mg of polysulphated glycosaminoglycan (PSGAG) IM every five days for seven treatments beginning 24 h after injection of collagenase. The control group received saline at the same time periods. Ultrasound examination of each limb was performed on days 1, 3, 5, and 7 post-injection and weekly thereafter for eight weeks. An image analysis system was used to measure the proportion of tendon area damaged in mm2 on the recorded images, and these values were plotted over time. The horses were euthanatized at eight weeks and histological evaluation was performed on longitudinal sections of excised tendons. Results. The size of the tendon core defects created by the collagenase enzyme, represented as the proportion of area damaged, decreased significantly faster in the treatment group ( <0.01). Histologic evaluation of the core defects confirmed what was seen sonographically. Conclusion. Polysulphated glycosaminoglycans had a positive effect on tendon healing in a collagenase induced tendinitis model. Clinical relevance. Polysulphated glycosaminoglycans may be beneficial in managing clinical cases of tendinitis.
Eight horses had experimental core defects induced in the superficial digital flexor tendon of both forelimbs. One group of four horses received PSGAG IM every 5 days for seven treatments. The control group received saline. The core defects in the PSGAG treatment group developed echogenic ultrasound patterns earlier, and the mean ratio of area of the tendon decreased significantly faster in the treatment group.