Investigation of protein content of synovial fluids with DSC in different arthritides

In the case of joint diseases, as a result of the process induced by the pathophysiological factors, the small articular structures that have pilled result in a qualitative and quantitative modification of the composition of the synovial fluid (SF). The analysis of this fluid offers a unique opportunity to study the joint diseases. In our study, 28 cases of acute knee joint meniscus injuries, transient knee joint synovitis, or degenerative knee joint destruction were studied. Following the collection and storage of SF, removed on the basis of the sample collection protocol, they were denatured in a SETARAM Micro DSC-II calorimeter with a scanning rate 0.3 K min −1 in the 20–90 °C temperature range. 4–4 samples from the “normal” SF batch were inoculated by two different strains of bacteria [ Staphylococcus aureus and Staphylococcus epidermidis ] with 10 −3 colony-forming unit. Thermoanalytical changes of the proteins found in the SF were studied by a SETARAM Micro DSC-II, in the laboratory of the Biophysical Institute. The maximum denaturation temperature of the proteins being in the SF with different severity varied according to the criterion of the radiological scaling of osteoarthritis made by the Kellgren–Lawrence criterion. The decomposition of the scans showed the degree of the damage in case of SF as well as in the inoculated samples. Knowing the denaturing properties of temperature-dependent protein molecules in SF, DSC can be used to design and develop intra-articular lubricant additives that effectively enhance protein stability and contribute to a reduction in joint wear.