Effects of treadmill training and EVOO enriched diet on cartilage degeneration in rats with ACLT.

Abstract

The beneficial effects of Extra Virgin Olive Oil (EVOO), the main fat source in Mediterranean diet, are widely studied thanks to its anti-inflammatory and antioxidant properties. Lubricin is a chondroprotective glycoprotein, with lubricant properties. A joint injury causes an increased cytokine expression, associated with decreased lubricin synthesis and predisposition to cartilage degeneration. The aim of this study was to evaluate the beneficial role of EVOO-enriched diet and physical activity, on osteoarthritic cartilage of rats. These effects were assessed through lubricin and interleukin-6 expression in rat joint tissues. Osteoarthritis was induced mechanically by anterior cruciate ligament transection (ACLT). Forty-eight 3-month-old male Wistar rats were used for this study. Experiments and surgical procedures for ACLT were performed in accordance with the guidelines of the Institutional Animal Care and Use Committee (I.A.C.U.C.) of the University of Catania, European Community Council Directive and the Italian Animal Protection Law (Protocol n. 2112015-PR, Italian Ministry of Health). The 48 animals were divided into 6 groups: 1 – control rats (no ACLT, common die); 2 – rats with ACLT and common diet (experimental control); 3 – rats with ACLT, common diet and treadmill training; 4 – rats with ACLT, Sicilian EVOO and treadmill training; 5 – rats with ACLT, Tunisian EVOO and treadmill training; 6 – rats with ACLT, Tunisian EVOO and leaves extract and treadmill training. To this purpose, we performed histomorphometric, histological, immunocytochemical, immunohistochemical and biochemical analysis for lubricin and interleukin-6 evaluations in articular cartilage and synovial fluid of rats. Furthermore, skeletal muscle (anterior tibial) and liver tissue were used to perform histological analyses to exclude respectively hepatic steatosis and sarcopenia. The results showed the beneficial effect of physical activity and EVOO supplementation on the rat articular cartilage. ACLT determined an increase in interleukin-6 expression and a significant decrease in the lubricin expression, while physical activity and EVOO supplemented diet, determined that the values returned to a normal level when compared to the control group. Moreover, EVOO does not cause hepatic steatosis and muscle fibers of all groups did not show damaged histological structure. Our findings suggest that mechanical stimulation is able to increase the release of lubricin in articular cartilage, while the anti-inflammatory properties of EVOO reduces the expression of interleukin-6. In conclusion, the results showed a beneficial effect of the conjunction of EVOO-based diet, corresponding to the Mediterranean diet, and physical activity on the preservation of articular cartilage tissue. Support or Funding Information This study was supported by the University Research Project Grant (Triennial Research Plan 2016–2018), University of Catania, Italy. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.