Combined use of Olfactory Mucosal Mesenchymal Stem Cells Conditioned Medium and Neural Guide Conduits Promotes Nerve Regeneration in an Ovine Model

Rui Alvites^1,2,3,4Bruna Lopes^1,2,3André Filipe Monteiro Coelho^1,2,3Ana Catarina Sousa^1,2,3Patrícia Sousa^1,2,3Alícia De Sousa Moreira^1,2,3Alexandra Rêma^1,2,3Maria Simões^1,2,3,4Ana Lúcia Luís^1,2,3Carla Mendonça^1,2,3Justina Oliveira^1,5,6Isabel Pires^1,5,6Bruna Silva^7,8Filipa João⁹Miriam Metafune¹⁰Francesca Bertone¹⁰Stefania Raimondo¹⁰Luis Atayde^1,2,3Nuno M. Alves^7,8Ana Colette Maurício^1,2,3*

• ¹AL4Animals, Lisbon, Portugal
• ²Centre for the Studies of Animal Science, Institute of Agrarian and Agri-Food Sciences and Technologies, University of Oporto, Porto, Portugal
• ³ICBAS, School of Medicine and Biomedical Sciences, Institute of Biomedical Sciences Abel Salazar, University of Porto, Porto, Porto, Portugal
• ⁴Cooperativa de Ensino Superior Politécnico e Universitário, Gandra, Porto, Portugal
• ⁵University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
• ⁶Veterinary and Animal Research Center, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal
• ⁷Polytechnic Institute of Leiria, Leiria, Leiria, Portugal
• ⁸Center for Rapid and Sustainable Product Development, Polytechnic Institute of Leiria, Marinha Grande, Leiria, Portugal
• ⁹Faculty of Human Motricity, University of Lisbon, Dafundo, Portugal
• ¹⁰University of Turin, Turin, Piedmont, Italy

Peripheral nerve injuries remain a significant clinical challenge, particularly in severe neurotmesis injuries requiring complex therapeutic interventions to restore functionality. This study evaluated the pro-regenerative potential of combining neural guide conduits with conditioned medium from olfactory mucosa mesenchymal stem cells, compared to gold-standard surgical techniques, in a validated ovine model of common peroneal nerve injury. Recovery was assessed over 24 weeks using functional, kinematic, ultrasonographic, and electrophysiological evaluations, complemented by post-mortem nerve stereology and muscle histomorphometry. All therapeutic approaches promoted nerve and muscle regeneration, resulting in notable functional and structural improvements. However, irregularities were observed, as neural guide conduits and conditioned medium did not consistently outperform standard techniques. Additionally, recovery often fell short of normal values in the control group, highlighting the complexity of peripheral nerve regeneration in challenging surgical scenarios. These findings underscore the translational potential of biomaterials and cell conditioned mediumbased therapies while emphasizing the need for further research in complex animal models before its application in real clinical cases. Such studies are essential to refine therapeutic strategies, address observed irregularities and establish cell conditioned medium as a viable tool in peripheral nerve regeneration and repair.