N-acetylcysteine effects on a murine model of chronic critical limb ischemia.

During chronic limb ischemia, oxidative damage and inflammation are described. Besides oxidative damage, the decrease of tissue oxygen levels is followed by several adaptive responses. The purpose of this study was to determine whether supplementation with N-acetylcysteine (NAC) is effective in an animal model of chronic limb ischemia. Chronic limb ischemia was induced and animals were treated once a day for 30 consecutive days with NAC (30mg/kg). After this time clinical scores were recorded and soleus muscle was isolated and lactate levels, oxidative damage and inflammatory parameters were determined. In addition, several mechanisms associated with hypoxia adaptation were measured (vascular endothelial growth factor - VEGF and hypoxia inducible factor - HIF levels, ex vivo oxygen consumption, markers of autophagy/mitophagy, and mitochondrial biogenesis). The adaptation to chronic ischemia in this model included an increase in muscle VEGF and HIF levels, and NAC was able to decrease VEGF, but not HIF levels. In addition, ex vivo oxygen consumption under hypoxia was increased in muscle from ischemic animals, and NAC was able to decrease this parameter. This effect was not mediated by a direct effect of NAC on oxygen consumption. Ischemia was followed by a significant increase in muscle myeloperoxidase activity, as well as interleukin-6 and thiobarbituric acid reactive substances species levels. Supplementation with NAC was able to attenuate inflammatory and oxidative damage parameters, and improve clinical scores. In conclusion, NAC treatment decreases oxidative damage and inflammation, and modulates oxygen consumption under hypoxic conditions in a model of chronic limb ischemia.

Intra-articular Treatment with Triamcinolone Hexacetonide Associated with Gold Nanoparticles Reduces Cartilage Degeneration in an Animal Model of Osteoarthritis.

INTRODUCTION: The association between triamcinolone hexacetonide (TH) and gold nanoparticles (GNPs) represents a promising treatment due to the potential anti-inflammatory and antioxidant effects of these compounds. In this study, we evaluated the effects of intra-articular treatment of TH associated with GNPs in a mechanical model of osteoarthritis (OA). METHODS: Fifty Wistar rats were divided into five groups: Sham; OA; OA+TH; OA+GNPs; OA+TH-GNPs. Both applications were performed 30 and 60 days after the model was induced. After 30 days of the last application, the animals were euthanized. RESULTS: Only the combined treatment with TH and GNPs promoted a reduction in proinflammatory cytokines and an increase in anti-inflammatory cytokines. The OA+TH-GNPs group obtained a significant reduction in the production of oxidants and oxidative damage markers while an increase in antioxidants. Histologically, all treated groups showed results of a significant increase in cartilage thickness and chondrocyte count, the OA+TH-GNPs group had similar behavior to the group without osteoarthritis, with significantly smaller amounts of chondrocytes than the OA group. CONCLUSION: The intra-articular use of TH associated with GNPs may be able to prevent the progression of the pathology and minimize joint degradation.

The effectiveness of treadmill and swimming exercise in an animal model of osteoarthritis.

Introduction: Osteoarthritis (OA) is considered an inflammatory and degenerative joint disease, characterized by loss of hyaline joint cartilage and adjacent bone remodeling with the formation of osteophytes, accompanied by various degrees of functional limitation and reduction in the quality of life of individuals. The objective of this work was to investigate the effects of treatment with physical exercise on the treadmill and swimming in an animal model of osteoarthritis. Methods: Forty-eight male Wistar rats were divided (n=12 per group): Sham (S); Osteoarthritis (OA); Osteoarthritis + Treadmill (OA + T); Osteoarthritis + Swimming (OA + S). The mechanical model of OA was induced by median meniscectomy. Thirty days later, the animals started the physical exercise protocols. Both protocols were performed at moderate intensity. Forty-eight hours after the end of the exercise protocols, all animals were anesthetized and euthanized for histological, molecular, and biochemical parameters analysis. Results: Physical exercise performed on a treadmill was more effective in attenuating the action of pro-inflammatory cytokines (IFN-γ, TNF-α, IL1-ß, and IL6) and positively regulating anti-inflammatories such as IL4, IL10, and TGF-ß in relation to other groups. Discussion: In addition to maintaining a more balanced oxi-reductive environment within the joint, treadmill exercise provided a more satisfactory morphological outcome regarding the number of chondrocytes in the histological evaluation. As an outcome, better results were found in groups submitted to exercise, mostly treadmill exercise.