The purpose of this study was to investigate the influence of moderate physical activity (MPA) on the expression of osteoarthritis (OA)-related (IL-1β, IL-6, TNF-α, MMP-13) and anti-inflammatory and chondroprotective (IL-4, IL-10, lubricin) biomarkers in the synovium of an OA-induced rat model. A total of 32 rats were divided into four groups: Control rats (Group 1); rats performing MPA (Group 2); anterior cruciate ligament transection (ACLT)-rats with OA (Group 3); and, ACLT-rats performing MPA (Group 4). Analyses were performed using Hematoxylin & Eosin (H&E) staining, histomorphometry and immunohistochemistry. In Group 3, OA biomarkers were significantly increased, whereas, IL-4, IL-10, and lubricin were significantly lower than in the other experimental groups. We hypothesize that MPA might partake in rescuing type B synoviocyte dysfunction at the early stages of OA, delaying the progression of the disease.

The Coronavirus Disease 2019 (COVID-19) pandemic has forced the hardest-hit populations, like Italians, to radically change their daily habits, starting with social distancing, strict preventive measures, and self-isolation. These precautions also apply to sport-related facilities and activities. The difficulty to practice physical activity during this dramatic moment in time adds to the risks associated with sedentary habits, due to staying all the time at home. Here, the importance and the benefits of maintaining exercise routine, even at home, are emphasized in order to avoid the consequences of inactivity.

The COVID-19 outbreak forced Italian students to reduce their daily activities, inducing a seden-tary attitude that was worsened by distanced learning. This study aimed to survey the physical activity levels that were maintained before and during the social restrictions following the pan-demic, their correlation to musculoskeletal pain, as well as analyzing the impact of these COVID-19 restrictions on pain and fatigue that affects daily life activities. A total of 2044 students completed the online questionnaire, of which the results of 1654 participants were eligible. Before the pandemic, the levels of physical activity were distributed as: 19.9% no activity, 30.1% light ac-tivity, 21.5% moderate activity, and 28.5% high activity. After one year of the pandemic, 30.6% of the participants were inactive, 48.1%, 10.9%, and 10.5% stated as maintaining, respectively, light, moderate and high levels of physical activity. Furthermore, 43.5% reported neck pain and 33.5% stated to experience low back pain. Physical activity levels lower than 150 min/week may have predisposed students to suffer from neck pain (1.95 OR at 95% CI, 1.44–2.64) and low back pain (1.79 OR at 95% CI, 1.29–2.49). A positive correlation between physical activity levels, Verbal Descriptive Scale (VDS), and pain frequency have been observed for neck and low back pain (p-value < 0.05). Finally, low physical activity levels were associated with musculoskeletal pain onset and pain worsening.

The multifold benefits of regular physical exercise have been largely demonstrated in human and animal models. Several studies have reported the beneficial effects of physical activity, both in peripheral tissues and in the central nervous system (CNS). Regular exercise improves cognition, brain plasticity, neurogenesis and reduces the symptoms of neurodegenerative diseases, making timeless the principle of “mens sana in corpore sano” (i.e., a healthy mind in a healthy body). Physical exercise promotes morphological and functional changes in the brain, acting not only in neurons but also in astrocytes, which represent the most numerous glial cells in the brain. The multiple effects of exercise on astrocytes comprise the increased number of new astrocytes, the maintenance of basal levels of catecholamine, the increase in glutamate uptake, the major release of trophic factors and better astrocytic coverage of cerebral blood vessels. The purpose of this review is to highlight the effects of exercise on brain function, emphasize the role of astrocytes in the healthy CNS, and provide an update for a better understanding of the effects of physical exercise in the modulation of astrocyte function.

The management of chondral defects represents a big challenge because of the limited self-healing capacity of cartilage. Many approaches in this field obtained partial satisfactory results. Cartilage tissue engineering, combining innovative scaffolds and stem cells from different sources, emerges as a promising strategy for cartilage regeneration. The aim of this study was to evaluate the capability of a cell-free collagen I-based scaffold to promote cartilaginous repair after orthotopic implantation in vivo. Articular cartilage lesions (ACL) were created at the femoropatellar groove in rat knees and cell free collagen I-based scaffolds (S) were then implanted into right knee defect for the ACL-S group. No scaffold was implanted for the ACL group. At 4-, 8- and 16-weeks post-transplantation, degrees of cartilage repair were evaluated by morphological, histochemical and gene expression analyses. Histological analysis shows the formation of fibrous tissue, at 4-weeks replaced by a tissue resembling the calcified one at 16-weeks in the ACL group. In the ACL-S group, progressive replacement of the scaffold with the newly formed cartilage-like tissue is shown, as confirmed by Alcian Blue staining. Immunohistochemical and quantitative real-time PCR (qRT-PCR) analyses display the expression of typical cartilage markers, such as collagen type I and II (ColI and ColII), Aggrecan and Sox9. The results of this study display that the collagen I-based scaffold is highly biocompatible and able to recruit host cells from the surrounding joint tissues to promote cartilaginous repair of articular defects, suggesting its use as a potential approach for cartilage tissue regeneration.

Deficiency in vitamin D (Vit D) has been widely associated with several musculoskeletal diseases. However, the effects of the exogenous Vit D supplementation are still unclear in the prevention of the latter, especially in the cartilage developmental period. The aim of this study was to compare the effects of Vit D supplementation and restriction on the articular cartilage development in healthy young sedentary rats. To this aim, twelve nine-week-old healthy Sprague–Dawley male rats were subjected to Vit D-based experimental diets: R, with a content in Vit D of 1400 IU/kg; R-DS, with a Vit D supplementation (4000 IU/kg); R-DR, with a Vit D restriction (0 IU/kg) for 10 weeks. The morphology, thickness and expression of cartilage-associated molecules such as collagen type II/X, lubricin and Vit D receptor (VDR), were assessed. Histological, histomorphometric and immunohistochemical evaluations were made on rat tibial cartilage samples. In the present experimental model, restriction of Vit D intake induced: The lower thickness of cartilage compared both to R (p = < 0.0001) and R-DS (p = < 0.0001); reduction of proteoglycans in the extracellular matrix (ECM) compared both to R (p = 0.0359) and R-DS (p = < 0.0001); decreased collagen II (Col II) with respect both to R (p = 0.0076) and R-DS (p = 0.0016); increased collagen X (Col X) immunoexpression when compared both to R (p = < 0.0001) and R-DS (p = < 0.0001), confirming data from the literature. Instead, supplementation of Vit D intake induced: Higher cartilage thickness with respect both to R (p = 0.0071) and R-DR (p = < 0.0001); increase of ECM proteoglycan deposition compared both to R (p = 0.0175) and R-DR (p = < 0.0001); higher immunoexpression of lubricin with respect both to R (p = 0.001) and R-DR (p = 0.0008). These results suggest that Vit D supplementation with diet, already after 10 weeks, has a favorable impact on the articular cartilage thickness development, joint lubrication and ECM fibers deposition in a young healthy rat model.