Intra-articular treatment with hyaluronic acid associated with gold nanoparticles in a mechanical osteoarthritis model in Wistar rats.

This study aimed to evaluate the effects of intra-articular treatment with hyaluronic acid (HA) associated with GNPs in a mechanical model of osteoarthritis induced by median meniscectomy (MM). Fifty Wistar rats (2 months weighing between 250 and 300 g) were used, divided into five groups of 10 animals each: Sham, osteoarthritis (OA), OA + HA, OA + gold nanoparticles (GNPs), and OA + HA + GNPs. Intra-articular treatment was started 30 days after the model was induced, with a frequency of 2 weeks for 60 days. Fifteen days after the last application, the animals were euthanized with the removal of the joint tissue for biochemical and histological analysis. The model used was able to mimic osteoarthritis, characterized by the presence of high levels of proinflammatory cytokines, oxidative stress, and degeneration of joint surfaces (Grade III, according to SCORE OARSI). The isolated use of HA or GNPs provided beneficial results to the joint; however, only the group subjected to the association between HA and GNPs showed the attenuation of oxidative stress and reduced proinflammatory markers, with a simultaneous increase in levels of anti-inflammatory cytokines and growth factors. Upon histological analysis, only the OA + HA + GNPs group achieved the restoration of the thickness of the joint cartilage with reduced damage and return to the intact joint surface. The results found demonstrated that the association of GNPs with HA was able to reverse the deleterious effects caused by the model by inhibiting the progressive degeneration of joint surfaces, representing a promising treatment for osteoarthritis.

Effects of cryotherapy on the regeneration process and muscular mechanical properties after lacerative injury model.

Cryotherapy is a therapeutic modality widely used for the treatment of muscle injuries to control pain and inflammatory processes. This study aimed to investigate the effects of cryotherapy on the inflammatory and oxidative stress parameters and mechanical properties of, and pain in, the skeletal muscles of rats with lacerative muscle injury. The rats were anesthetized with 4% isoflurane and subjected to gastrocnemius muscle laceration injury. After injury, all animals in the intervention groups received cryotherapy treatment for 20 minutes using plastic bags containing crushed ice. The protocol comprised three daily applications at 3-hour intervals on the day of injury, with reapplication 24 hours later. Seventy-two male Wistar rats were divided into three groups: sham, muscle injury (MI), and MI + cryotherapy (MI + cryo). Muscle mechanical properties were analyzed by mechanical tensile testing on day 7 after injury. The MI + cryo group showed reduced TNF-α, IFN-γ, and IL1ß levels; elevated IL4, IL6, and IL10 levels; reduced oxidant production and carbonyl levels; and elevated sulfhydryl contents. Animals that underwent tissue cooling showed superoxide dismutase activity and glutathione levels close to those of the animals in the sham group. The MI and MI + cryo groups showed reduced values of the evaluated mechanical properties and lower mechanical thresholds compared to those of the animals from the sham group. Our results demonstrated that the proposed cryotherapy protocol reduced the inflammatory process and controlled oxidative stress but did not reverse the changes in the mechanical properties of muscle tissues or provide analgesic effects within the time frame analyzed.