Abstract:Objective: To model the healing that umbilical cord perivascular cells effect in equines, we have used human umbilical cord perivascular cells (HUCPVCs) to repair tendon damage in a collagenase tendon injury model in immunecompromised rats. Animals: 48 Nude rats (Crl:NIH-Foxn1 rnu ) of 200-250 g weight were used. Procedure: The Achilles tendon was exposed by blunt dissection and, using a 30G needle, 30 µl of either a mixture of cells (2 x10 5 ) and collagenase, or collagenase alone, was injected close to the musculotendinous junction in the direction of the osteotendinous junction. Results: Harvested tendons showed the presence of HUCPVCs at the site of injury, whose morphology changed from ovoid to elongated over the 30 post-injury experimental time period. Human genes for collagen type 1 and β-actin were expressed at all time points and there was also a significant increase in tendon tensile strength and stiffness by 30 days post-injury in the experimental group. Conclusion: HUCPVCs facilitated regeneration in our model through changes in collagen organization; cell shape and orientation; and increase in mechanical properties over those of the untreated controls. Clinical Relevance: Cell therapy has been shown to be effective in treating tendon injuries, especially in equines. We have recently isolated a mesenchymal cell population from equine umbilical cords that is analogous to a well-characterized HUCPVC population. Our results indicate that HUCPVCs are a putative cell source for treating tendon injuries; and this model could explain the benefits of using analogous cells in equines.

No abstract