201. The infrapatellar fat pad is affected by injury induced inflammation in the rabbit knee: use of dexamethasone to mitigate damage.
- Author
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Heard, Bryan, Solbak, Nathan, Chung, May, Achari, Yamini, Shrive, Nigel, Frank, Cyril, and Hart, David
- Subjects
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GLUCOCORTICOIDS , *DEXAMETHASONE , *INFLAMMATION treatment , *KNEE injury treatment , *LABORATORY rabbits - Abstract
Objective and design: The health of the infrapatellar fat pad (IFP) has been linked to pain, joint inflammation, and the onset of post-traumatic osteoarthritis. Thus, early inflammation effects on the IFP could have long term sequelae on joint integrity. This study was designed to characterize the natural history of the IFP in a model of surgically induced knee injury and inflammation, and to test the efficacy of one intra-articular (IA) administration of dexamethasone (DEX) immediately following surgery. Methods: An IA bone drill hole injury to the rabbit knee was conducted and immediately treated with DEX ( n = 12). Early and late post-surgical time-points were investigated (48 h and 9 weeks) and the outcome measures were analysis of IFP histology, mRNA levels for relevant molecules, and protein levels for a subset of cytokines. Data were analyzed against a surgical control (injury without treatment; n = 12), a surgical sham (capsular incision only; n = 12), and normal control ( n = 6). Treatment: Single IA injection of DEX (0.5 mg/kg), administered at the completion of surgery. Results: IFPs from injured joints exhibited significantly increased cellularity and early fibrosis at 48 h post surgery. While the histological inflammation from a capsular incision alone resolved, knee injured animals progressed to a significantly more fibrotic IFP by 9 weeks. DEX significantly lowered histological scores at 48 h, but not at the 9 weeks. DEX did not influence mRNA levels for IL-1β, 6, and 8, however, protein analysis indicated that IL-8 levels were lower in DEX treated joints. DEX resulted in significantly elevated expression of mRNA for MCP-1, leptin, and VEGF. Conclusion: One IA administration of a glucocorticoid appears to mitigate the initial inflammation within the joint, but is not sufficient to protect the joint to 9 weeks post-surgery. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
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