ANALYSIS OF HEAT-SHOCK PROTEINS AND CYTOKINES EXPRESSED DURING EARLY STAGES OF OSTEOARTHRITIS IN A MOUSE MODEL

Objective: Osteoarthritis (OA) is a debilitating disease of the joints . The joints of affected individuals are characterized by a progressiv e degeneration of articular cartilage leading to inflammation and pain . The expression of heat shock proteins (HSPs) is a ubiquitous self-pr otective mechanism of all cells under stress, furthermore, the synoviu m of osteoarthritic individuals contains high levels of cytokines. Thi s study seeks to establish the role of HSPs and cytokines in OA. METHO DS: We have investigated the presence of HSPs and cytokines in articul ar cartilage during early stages of OA in a mouse that is known to dev elop spontaneous OA lesions (C57 black mouse). The articular cartilage from closely related mice (C57BL/6) was used as control. Messenger RN As (mRNAs) for HSPs (HSP32, HSP47, HSP60, HSP70, HSP84 and HSP86) and cytokines [interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma)] w ere detected by reverse transcription-polymerase chain reaction (RT-PC R). Results: The mRNA levels of HSP47, HSP70, HSP86, IL-6, and IFN-gam ma were up-regulated in the cartilage of C57 black mice, whereas, the level of expression of HSP32, HSP60, HSP84 and IL-1 beta remained unch anged. Furthermore, the expression of IL-1 beta, IL-6, TNF-alpha and I FN-gamma mRNA was associated with expression of HSP60, HSP47, HSP70 an d HSP70/HSP86 mRNA, respectively. Conclusions: The findings in this st udy suggest that chondrocytes are conditioned under non-physiological stress during early stages of OA, In addition, among HSPs, HSP70 was a ssociated with two different highly expressed cytokines in C57 black m ice, indicating the possible role of HSP70 as a characteristic indicat or of early stage of OA.