title: Improved biomechanical and biological outcomes in the MRL/MpJ murine strain following a full-length patellar tendon injury.
abstract: Musculoskeletal injuries greatly affect the U.S. population and current clinical approaches fail to restore long-term native tissue structure and function. Tissue engineering is a strategy advocated to improve tendon healing; however, the field still needs to establish biological benchmarks for assessing the effectiveness of tissue-engineered structures. Investigating superior healing models, such as the MRL/MpJ, offers the opportunity to first characterize successful healing and then apply experimental findings to tissue-engineered therapies. This study seeks to evaluate the MRL/MpJ's healing response following a central patellar tendon injury compared to wildtype. Gene expression and histology were assessed at 3, 7, and 14 days following injury and mechanical properties were measured at 2, 5, and 8 weeks. Native patellar tendon biological and mechanical properties were not different between strains. Following injury, the MRL/MpJ displayed increased mechanical properties between 5 and 8 weeks; however, early tenogenic expression patterns were not different between the strains. Furthermore, expression of the cyclin-dependent kinase inhibitor, p21, was not different between strains, suggesting an alternative mechanism may be driving the healing response. Future studies will investigate collagen structure and alignment of the repair tissue and characterize the complete healing transcriptome to identify mechanisms driving the MRL/MpJ response.
authors.affiliation: Biomedical Engineering Program, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, Ohio.
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Lalley
authors.affiliation: Department of Reconstructive Sciences, College of Dental Medicine, University of Connecticut Health Center, Farmington, Connecticut.
authors.forename: Nathaniel A
authors.initials: NA
authors.lastname: Dyment
authors.affiliation: Department of Orthopaedic Surgery, College of Medicine, University of Cincinnati, Cincinnati, Ohio.
authors.forename: Namdar
authors.initials: N
authors.lastname: Kazemi
authors.affiliation: Department of Orthopaedic Surgery, College of Medicine, University of Cincinnati, Cincinnati, Ohio.
authors.forename: Keith
authors.initials: K
authors.lastname: Kenter
authors.affiliation: Biomedical Engineering Program, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, Ohio.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Gooch
authors.affiliation: Department of Reconstructive Sciences, College of Dental Medicine, University of Connecticut Health Center, Farmington, Connecticut.
authors.forename: David W
authors.initials: DW
authors.lastname: Rowe
authors.affiliation: Biomedical Engineering Program, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, Ohio.
authors.forename: David L
authors.initials: DL
authors.lastname: Butler
authors.affiliation: Biomedical Engineering Program, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, Ohio.
authors.forename: Jason T
authors.initials: JT
authors.lastname: Shearn
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D049109:Cell Proliferation; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D008297:Male; D008810:Mice, Inbred C57BL; D023421:Models, Animal; D017847:Patellar Ligament / Q000293:injuries / Q000502:physiology; D013708:Tendon Injuries; D014945:Wound Healing
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21
keywords: MRL/MpJ; p21; tendon; tendon healing