Journal article
Antioxidants Block Cyclic Loading Induced Chondrocyte Death
The Iowa orthopaedic journal, Vol.27, pp.1-8
01/01/2007
PMCID: PMC2150661
PMID: 17907423
Appears in Diamond Open Access
Abstract
Articular cartilage in congruous joints benefits from the moderate stresses and strains associated with normal cyclic loading. However, loading of joints with surface incongruities can lead to local stress and strain elevation at “step-off” sites where cartilage is not fully buttressed by surrounding matrix. Excessive stresses and strains predicted to occur at such sites may induce apoptosis, a process thought to promote cartilage degeneration and osteoarthritis (OA) through chondrocyte attrition. We hypothesized that the induction of apoptosis is mediated by oxidants, and that antioxidants can reduce elevated stress-induced chondrocyte attrition. To test this we exposed cylindrical cartilage explants from human articular cartilage to radially unconfined cyclic axial compression (3600 cycles, 1 Hz, 50% duty cycle) using two different physiologic loads (2MPa and 5 MPa). We found that 30% of chondrocytes in the superficial zone died within 24 hours of exposure to loading with 5 MPa axial compression, whereas mortality was limited to less than 15% with 2 MPa axial compression. Similarly, lactate accumulation in the medium was suppressed by compression with 5 MPa, but not 2 MPa. Approximately 80% of cell death induced by 5 MPa compression was blocked by pre-incubation of the explants in a variety of anti-oxidants including vitamin E, n-acetyl cysteine (NAC), and a superoxide dismutase mimetic (SOD). SOD and NAC also prevented the suppression of lactate secretion after 5 MPa compression. These observations support the hypothesis that the harmful effects of abnormal cyclic loading are mediated by oxidants and suggest that treatments to prevent OA may include methods of minimizing oxidative damage to chondrocytes.
Details
- Title: Subtitle
- Antioxidants Block Cyclic Loading Induced Chondrocyte Death
- Creators
- B R BeecherJ A MartinD R PedersenA D HeinerJ A Buckwalter
- Resource Type
- Journal article
- Publication Details
- The Iowa orthopaedic journal, Vol.27, pp.1-8
- PMID
- 17907423
- PMCID
- PMC2150661
- NLM abbreviation
- Iowa Orthop J
- ISSN
- 1541-5457
- eISSN
- 1555-1377
- Publisher
- Dept. of Orthopaedics, The University of Iowa; United States
- Language
- English
- Date published
- 01/01/2007
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Stead Family Department of Pediatrics; Pharmaceutical Sciences and Experimental Therapeutics; Orthopedics and Rehabilitation; Injury Prevention Research Center
- Record Identifier
- 9984040567802771
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