The effects of physical activity on apoptosis and lubricin expression in articular cartilage in rats with glucocorticoid-induced osteoporosis

Abstract

Glucocorticoids are considered the most powerful anti-inflammatory and immunomodulating drugs. However, a number of side-effects are well documented in different diseases, including articular cartilage, where increases or decreases in the synthesis of hormone-dependent extracellular matrix components are seen. The objective of this study has been to test the effects of procedures or drugs affecting bone metabolism on articular cartilage in rats with prednisolone-induced osteoporosis and to evaluate the outcomes of physical activity with treadmill and vibration platform training on articular cartilage. The animals were divided into 5 groups, and bone and cartilage evaluations were performed using whole-body scans and histomorphometric analysis. Lubricin and caspase-3 expression were evaluated by immunohistochemistry, Western blot analysis and biochemical analysis. These results confirm the beneficial effect of physical activity on the articular cartilage. The effects of drug therapy with glucocorticoids decrease the expression of lubricin and increase the expression of caspase-3 in the rats, while after physical activity the values return to normal compared to the control group. Our findings suggest that it might be possible that mechanical stimulation in the articular cartilage could induce the expression of lubricin, which is capable of inhibiting caspase-3 activity, preventing chondrocyte death. We can assume that the physiologic balance between lubricin and caspase-3 could maintain the integrity of cartilage. Therefore, in certain diseases such as osteoporosis, mechanical stimulation could be a possible therapeutic treatment. With our results we can propose the hypothesis that physical activity could also be used as a therapeutic treatment for cartilage disease such as osteoarthritis.

Effects of exercise on physical limitations and fatigue in rheumatic diseases

“…Risk factors include age [32,33] , mechanical factors [33] , obesity [34] , and inflammation [35,36] . The key intervention in the management of OA is exercise therapy [37,38] . It is well known that exercise training affects the articular cartilage metabolism and modifies the cartilaginous structure by a mechanotransduction response [37][38][39] .…”

“…The key intervention in the management of OA is exercise therapy [37,38] . It is well known that exercise training affects the articular cartilage metabolism and modifies the cartilaginous structure by a mechanotransduction response [37][38][39] . Biomechanical stimulus generated by dynamic compression, during a moderate exercise, can reduce the synthesis of proteolytic enzymes, regulating the metabolic balance and preventing the progression of the disease [40,41] .…”

The Effect of Mechanical Loading on Articular Cartilage

“…During the joint loading, the PGAs are compressed and they permit the distribution of the force on the rest of the joint surface, thereby reducing the pressure on the AC [9]. The joint surface is lined with a glycoprotein called lubricin, produced by both chondrocytes and synoviocytes [10][11][12]. It has boundary lubrication properties, facilitating low friction levels at the interfacing surfaces of AC [10][11][12].…”

New perspectives for articular cartilage repair treatment through tissue engineering: A contemporary review

“…If the rehabilitation period is too short, the cartilage repair might be put under too much stress, causing the repair to fail [2] . Over the years a variety of cartilage restorative procedures have been developed for athletes to address focal, full-thickness cartilaginous defects in the knee joint [56] . In most rehabilitation protocols, continuous passive motion or range of motion exercises are performed within the first day after injury or surgery.…”

“…The goal is to restore full function in each patient as quickly as possible by facilitating a healing response without overloading the healing articular cartilage [2] . A patient, lesion, and sportsspecific approach is required on the part of the trainer or physical therapist to gradually restore knee joint function and strength so that the athlete may be able to return to competitive play [56] . In this paper review we also take the opportunity to remind readers of the importance of a healthy lifestyle, including physical activity (mild exercise) and balanced diet such as Mediterranean Diet, in the medical therapy to prevent OA disease, in order to preserve the articular cartilage and then the entire joint [59] .…”