Urinary bladder matrix does not improve tenogenesis in an in vitro equine model.

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Orthopedics

Background:

• Tendon injuries result in scar tissue with poor structural integrity, increasing reinjury risk.
• Extracellular matrix (ECM) scaffolds show promise for improving tendon healing.
• Porcine urinary bladder matrix (UBM) is a potential biomaterial for tissue regeneration but its efficacy in tendon repair is understudied.

Purpose of the Study:

• To evaluate the efficacy of UBM in promoting matrix organization and tenogenesis within a tendon ECM hydrogel.
• To test the hypothesis that UBM addition improves matrix organization and cell differentiation in tendon constructs.

Main Methods:

• A novel in vitro model using rat tail tendon ECM hydrogels seeded with equine bone marrow cells was developed.
• Hydrogels were fabricated with or without UBM, subjected to static tension, and analyzed at 7 and 21 days.
• Analyses included construct contraction, cell viability, histology, biochemistry, and gene expression.

Main Results:

• UBM-treated constructs showed significant contraction by day 7, unlike controls, with both groups contracting by day 21.
• Cells remained viable and elongated along tension lines, indicating matrix organization and differentiation in both groups.
• No significant differences were observed between UBM and control groups in nuclear morphology, DNA, glycosaminoglycan content, or specific gene expression markers (Decorin, MMP-13, Scleraxis, Mohawk, COMP).

Conclusions:

• The novel in vitro tendon ECM hydrogel model demonstrated substantial matrix organization and cell differentiation.
• The addition of UBM did not significantly improve matrix organization or tenogenesis compared to tendon ECM alone.
• Further research is needed to explore UBM's potential in tendon repair, possibly through modified formulations or different application methods.