AimTo determine the dose of monosodium iodoacetate (MIA) required to induce oxidative stress, as well as pain and edema; to confirm the induction of knee osteoarthritis (OA) symptoms in rats by the presence of reactive oxygen species (ROS) and reduction of antioxidant agents; and to verify the presence of histopathological injury in these affected joints.MethodBiological markers of oxidative stress, pain, knee edema, and cartilage degeneration provided by different doses of MIA (0.5; 1.0 or 1.5 mg) in rat knee joints were analyzed. The animal evaluations were conducted during 15 days for mechanical and cold hypersensitivity, spontaneous pain and edema. After that, blood serum, intra‐articular lavage and structures of knee, spinal cord and brainstem were collected for biochemical analysis; moreover, the knees were removed for histological evaluation.ResultsThis study demonstrates that the highest dose of MIA (1.5 mg) increased the oxidative stress markers and reduced the antioxidant reactions, both in the focus of the lesion and in distant sites. MIA also induced the inflammatory process, characterized by pain, edema, increase in neutrophil count and articular damage.ConclusionThis model provides a basis for the exploration of underlying mechanisms in OA and the identification of mechanisms that may guide therapy and the discovery of OA signals and symptoms.

The clavicle is a bone whose development is related to the versatility of the thoracic limbs in mammals. Studies with vestigial structures are scarce and controversial, especially in the order Carnivora. The objective of this study was to verify the presence and to investigate the shape and constitution of the clavicle in neotropical carnivores. In order to do this, 108 cadavers of 19 different species were collected dead on highways and were analyzed. The clavicles were submitted to dissections, longitudinal length measurements, radiographs, histological sections and, in some cases, diaphanization. Sixteen of the 19 species had clavicles in both sides, being significantly larger (P < 0.05) and distinctly more radiopaque in the felids than in the other families. There were no macro or microscopic evidence of clavicle in the specimens of Nasua nasua (n = 6), Conepatus semistriatus (n = 2), and Conepatus chinga (n = 1). The clavicle of the males of Lycalopex gymnocercus, Galictis cuja, and Leopardus geoffroyi was significantly larger (P < 0.05). The predominating contour of the clavicles was a thin stick with cranial convexity. The histological sections demonstrated compact bone consisting of trabecula and lamellae filled by bone marrow and different levels of occupation by chondroid matrix. It can be proposed the clavicles of the order Carnivora, although vestigial and rarely absent, have their presence, constitution and shape more associated with the phylogenetic proximity and evolutionary history of the species than to the variety of movements the thoracic limbs perform in free‐living conditions. Anat Rec, 2019. © 2019 American Association for Anatomy Anat Rec, 303:1831–1841, 2020. © 2019 American Association for Anatomy