Identification of changes in circadian clock genes in osteoarthritis following heat shock

Abstract

Introduction. Osteoarthritis (OA) is a prevalent condition that causes pain, stiffness, and decreased joint function due to the gradual degradation of articular cartilage. With an ageing global population, there is an urgent need for effective prevention and treatment methods. Recent studies suggest that circadian rhythms, which regulate various physiological processes, may also play a role in cartilage health. This study investigates the influence of heat sleeve therapy on the circadian clock-controlled regulation of cartilage homeostasis in human cartilage affected by OA. The aim of this study is to extend the current understanding of how heat induction influences the circadian regulation of cartilage homeostasis in OA-affected knee samples. Methods. This quantitative study compares the effects of heat sleeve therapy on articular cartilage between two groups: a control group kept at 18°C and an experimental group subjected to higher temperatures. Histological examinations were performed using Safranin O/Fast Green, Haematoxylin and Eosin (H&E), and RGB Trichrome staining to assess structural changes in the cartilage. Additionally, immunofluorescence labelling using Invitrogen's EVOS M7000 was employed to analyze the expression of clock genes Bmal1 and Clock. Result. The study found that heat sleeve therapy affected the expression of clock genes Bmal1 and Clock, as well as cartilage structure and composition. Histological staining revealed significant differences in proteoglycan concentration, tissue architecture, and collagen distribution between the control and heat-treated groups. These changes suggest that heat treatment may influence cartilage degradation and repair processes in OA. Conclusion. The results indicate that circadian rhythms and environmental stresses such as heat can impact cartilage health in OA. Understanding the role of clock genes in cartilage metabolism and stress responses could lead to new treatment targets for OA. Further research is needed to explore the potential therapeutic benefits of modulating circadian rhythms and heat stress responses in cartilage tissue.