Combination of chondroitin sulfate and hyaluronic acid increases amount of fibroblast, collagen and decreases adhesion of achilles tendon after repair

Background: This study was designed to evaluate the effects of chondroitin sulfate (CS) combined with hyaluronic acid (HA) on rat's post surgically repaired achilles tendon rupture at 21 day post injury. Methods: Achilles tendon of 28 male rats (Rattus Novergicus var wistar) were cut and repaired by modified Kessler technique and circular cast were applied after repair. Samples were allocated into four test group: group 1 as control had a simple tendon repair, group 2 which had hyaluronic acid administered at repair site, group 3 which had chondroitin sulfate per orally and group 4 which had combination of chondroitin sulfate per orally and hyaluronic acid administration at repair site. The rats were sacrificed at 21 days post-op and tendons were evaluated histopathologically to count the amount of fibroblast, peritendon adhesion (using microscopic Tang scoring system) and quantitative amount of collagen using colorimetric analysis. Results: Treatment groups (groups 2, 3, and 4) had a significantly increased amount of fibroblast (p < 0.05) and group 4 had significantly increased tendon healing time proved by abundant fibroblast transformed to tenocyte compared to other groups. In group 4, peritendinous adhesion significantly reduced (p < 0.05) and there were significantly increased amount of collagen in treatment groups compared to control group (p < 0.05) analyzed by colorimetric. Conclusions: These findings suggest that a combined treatment of chondroitin sulfate and hyaluronic acid could be an effective therapeutic regime in restoring the morphological properties of achilles tendon in rats model, and might provide useful knowledge for future clinical trial studies in tendon ruptures.