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Mitoprotective therapy prevents rapid, strain‐dependent mitochondrial dysfunction after articular cartilage injury
Author(s) -
Bartell Lena R.,
Fortier Lisa A.,
Bonassar Lawrence J.,
Szeto Hazel H.,
Cohen Itai,
Delco Michelle L.
Publication year - 2020
Publication title -
journal of orthopaedic research®
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.24567
Subject(s) - mitochondrion , osteoarthritis , cartilage , microbiology and biotechnology , population , medicine , biology , chemistry , pathology , anatomy , alternative medicine , environmental health
Posttraumatic osteoarthritis (PTOA) involves the mechanical and biological deterioration of articular cartilage that occurs following joint injury. PTOA is a growing problem in health care due to the lack of effective therapies combined with an aging population with high activity levels. Recently, acute mitochondrial dysfunction and altered cellular respiration have been associated with cartilage degeneration after injury. This finding is particularly important because recently developed mitoprotective drugs, including SS peptides, can preserve mitochondrial structure and function after acute injury in other tissues. It is not known, however, if cartilage injury induces rapid structural changes in mitochondria, to what degree mitochondrial dysfunction in cartilage depends on the mechanics of injury or the time frame over which such dysfunction develops. Similarly, it is unknown if SS‐peptide treatment can preserve mitochondrial structure and function after cartilage injury. Here, we combined fast camera elastography, longitudinal fluorescence assays, and computer vision techniques to track the fates of thousands of individual cells. Our results show that impact induces mechanically dependent mitochondrial depolarization within a few minutes after injury. Electron microscopy revealed that impact causes rapid structural changes in mitochondria that are related to reduced mitochondrial function, namely, fission and loss of cristae structure. We found that SS‐peptide treatment prior to impact protects the mitochondrial structure and preserves mitochondrial function at levels comparable with that of unimpacted control samples. Overall, this study reveals the vital role of mitochondria in mediating cartilage's peracute (within minutes) response to traumatic injury and demonstrates mitoprotection as a promising therapeutic strategy for injury‐induced cartilage damage.