Quantitative evaluation of very early cartilage damage in experimental osteoarthritis using scanning electron microscopy.

OBJECTIVE: To describe parametric changes observed using scanning electron microscopy (SEM) in very early stages in posttraumatic osteoarthritis (OA) models in mice. METHODS: Mice (5/group) had their knees subjected to anterior cruciate ligament transection (ACLT), ACLT plus meniscectomy (MNCT) or sham surgery, sacrificed after 3, 7 or 14 days, had the articular cartilage evaluated under optical microscopy using Osteoarthritis Research Society International (OARSI) parameters as well as cartilage thickness, roughness, and a damage index using SEM. RESULTS: Alterations of the cartilage under optical microscopy were not significantly relevant among groups. SEM analysis revealed reduction of femoral and tibial cartilage thickness in ACLT and MNCT groups at 7 and 14 days, with increased cartilage roughness in MNCT group as early as 3 days postsurgery, being sustained up to 14 days. Articular damage index was significantly higher at 14 days post surgery in ACLT and MNCT vs control groups. CONCLUSION: This is the first demonstration of very early quantitative changes in the cartilage of mice subjected to posttraumatic experimental OA using SEM, revealing increased roughness and thickness as early as 3 days post surgery. These changes may be used as early surrogates for later joint damage in experimental OA.

Translation, cultural adaptation and reproducibility of a Portuguese version of the Functional Index for Hand OsteoArthritis (FIHOA).

BACKGROUND: The Functional Index for Hand Osteoarthritis (FIHOA) is a simple, reliable, and reproducible specific instrument to evaluate hand OA that can be applied both in clinical practice and research protocols. In order to be used in Brazil, FIHOA has to be translated into Portuguese, culturally adapted and have the reliability of the translated FIHOA version tested, which is the purpose of this study. METHODS: The FIHOA was translated into Brazilian Portuguese and administered to 68 patients with hand OA recruited between May 2019 and February 2020. The test-retest was applied to 32 patients and the reliability was assessed using Spearman's correlation coefficient and intraclass correlation coefficient (ICC). The internal consistency reliability was evaluated using Cronbach's alpha. External construction validity was assessed using the Spearman's correlation test between FIHOA and pain, assessed with a Visual Analogue Scale (VAS), the Cochin Hand Functional Scale (CHFS) and Health Assessment Questionnaire (HAQ). RESULTS: The 30 participants that initially answered the translated version of the FiHOA did not report difficulties in understanding or interpreting the translated version. The test-retest reliability for the total score was strong (r = 0.86; ICC = 0.89). Mean differences (1.37 ± 0.68) using Bland Altman's analysis did not significantly differ from zero and no systematic bias was observed. Cronbach's alpha was also high (0.89) suggesting a strong internal coherence in the test items. There were also correlations between FIHOA and the CHFS (r = 0.88), HAQ (r = 0.64) and pain in the hands both at rest (r = 0.55) and in motion (r = 0.44). CONCLUSION: The translation of the FIHOA into Brazilian Portuguese proved a valid instrument for measuring the functional capacity of patients with hand OA who understand Brazilian Portuguese.

Osteoarticular involvement in sickle cell disease.

The osteoarticular involvement in sickle cell disease has been poorly studied and it is mainly characterized by osteonecrosis, osteomyelitis and arthritis. The most frequent complications and those that require hospital care in sickle cell disease patients are painful vaso-occlusive crises and osteomyelitis. The deoxygenation and polymerization of hemoglobin S, which results in sickling and vascular occlusion, occur more often in tissues with low blood flow, such as in the bones. Bone microcirculation is a common place for erythrocyte sickling, which leads to thrombosis, infarct and necrosis. The pathogenesis of microvascular occlusion, the key event in painful crises, is complex and involves activation of leukocytes, platelets and endothelial cells, as well as hemoglobin S-containing red blood cells. Osteonecrosis is a frequent complication in sickle cell disease, with a painful and debilitating pattern. It is generally insidious and progressive, affecting mainly the hips (femur head) and shoulders (humeral head). Dactylitis, also known as hand-foot syndrome, is an acute vaso-occlusive complication characterized by pain and edema in both hands and feet, frequently with increased local temperature and erythema. Osteomyelitis is the most common form of joint infection in sickle cell disease. The occurrence of connective tissue diseases, including rheumatoid arthritis and systemic lupus erythematosus, has rarely been reported in patients with sickle cell disease. The treatment of these complications is mainly symptomatic, and more detailed studies are required to understand the pathophysiological mechanisms involved in the complications and propose more adequate and specific therapies.

Analgesic activity of a polysaccharide in experimental osteoarthritis in rats.

Viscosupplementation efficacy has been related to the high molecular weight of hyaluronic acid-like compounds, as well as to gel formulation. We evaluated the effect of a galactomannan polysaccharide derived from Guar gum (GG) in joint pain in an osteoarthritis (OA) model. Wistar rats (six animals/group) were subjected to anterior cruciate ligament transection (ACLT-OA group). The OA group was compared to a false-operated group (sham). Joint pain was recorded daily, using the articular incapacitation test, until 7 days after ACLT. Solutions or gel preparations of GG (100 microg) or Hylan G-F 20 (100 microg), used as a comparator, were given intraarticularly (i.a.) at day 4 after ACLT. Controls received saline i.a. The OA group had significantly increased joint pain as compared to sham (P<0.001). GG, either as a gel or solution, significantly inhibited joint pain similar to the inhibition achieved with Hylan G-F20. This is the first demonstration that a galactomannan derived from GG reduces joint pain in experimental OA. This analgesia is independent of the colloidal state. We propose that the analgesic benefit of viscosupplementation may be due to an intrinsic carbohydrate-mediated mechanism rather than to the rheologic properties of the material.

[Zymosan induced arthritis in rats--mechanisms involved in hypernociception and cartilage lyses]. / Artrite induzida por zymosan em ratos--mecanismos envolvidos na hipernocicepçao e na lise da cartilagem articular.

The authors present the experience of the group in the study of the mechanisms of hypernociception (pain) and articular cartilage lesion in the zymosan-induced arthritis model in rats.

Blockade of leukotriene B4 prevents articular incapacitation in rat zymosan-induced arthritis.

We investigated whether leukotrienes mediate cell influx and articular incapacitation in zymosan-induced arthritis. Rats received 1 mg zymosan intra-articularly (i.a.). The hyperalgesia was measured using the rat articular incapacitation test. Cell influx, leukotriene B(4) and prostaglandin E(2) levels were assessed in the joint exudate, at 6 h. Groups received either the leukotriene B(4) synthesis inhibitor MK 886 (3-[1-(4-chlorobenzyl)-3-t-butyl-thio-5-isopropylindol-2-yl)]-2,2-dimethylpropanoic acid 30 min before or 2 h after the zymosan; 0.3-3 mg kg(-1) i.p.), the leukotrienes synthesis inhibitor BWA(4)C (N-(3-phenoxycinnamyl)-acetohydroxamic acid--2 h after the zymosan; 10 microg i.a.) or the peptido-leukotrienes antagonist sodium montelukast (30 min before and 2 h after the zymosan; 10 mg kg(-1) per os). MK 886 inhibited the articular incapacitation and cell influx, while reducing leukotriene B(4), but not prostaglandin E(2) levels. BWA(4)C inhibited the articular incapacitation. Sodium montelukast did not affect either of the parameters. The data suggest that leukotriene B(4) is involved in cell influx and articular incapacitation in zymosan arthritis.

Reactive nitrogen species scavenging, rather than nitric oxide inhibition, protects from articular cartilage damage in rat zymosan-induced arthritis.

1. The contribution of nitric oxide (NO) and peroxynitrite (PN) to inflammation in a zymosan-induced (1 mg, intra-articular, i.art.) rat model of arthritis was assessed by histopathology and by measuring the glycosaminoglycan (GAG) content of the articular cartilage. 2. Progression of the chronic synovitis in zymosan-induced arthritis (ZYA) was associated with increased nitrite and nitrotyrosine (3-NT) levels in the joint exudates that paralleled a progressive loss of the GAG content. An increase in 3-NT was also observed after i.art. PN. 3. The nonselective nitric oxide synthase (NOS) inhibitor l-N(G)-nitroarginine methyl ester (25-75 mg x kg(-1)day(-1)) or the selective inducible NOS inhibitor aminoguanidine (50-100 mg x kg(-1)day(-1)) given 1 h before (prophylactic) or 3 days after (therapeutic) injection of the zymosan ameliorated the synovitis, but worsened the GAG loss, as measured at the end of the experiment (day 7). 4. The PN scavenger uric acid (100-250 mg x kg(-1) i.p. four times daily) given prophylactically until the end of the experiment (day 14), in a dose compatible with its PN scavenging activity, significantly decreased both the synovitis and the GAG loss. 5. In conclusion, PN formation is associated with cartilage damage in addition to proinflammatory activity in ZYA. NOS inhibitors and a PN scavenger were able to reduce the cellular infiltration, while displaying opposite effects on cartilage homeostasis either by enhancing or ameliorating the damage, respectively.

Evidence that peroxynitrite affects human osteoblast proliferation and differentiation.

Peroxynitrite (PN), a nitric oxide (NO*)-derived anion, has been associated with NO* damage in various cell types. We examined the effects of adding PN to cultured human osteoblast-like (hOB) cells obtained after hip arthroplasty. Exposure to PN (0.1-0.4 mM) decreased both hOB proliferation and differentiation, measured by [3H]thymidine uptake and alkaline phosphatase production, respectively. Incubation with 3-morpholinosydnonimine (SIN-1; 0.25-1 mM), an NO* and O2- donor that leads to PN release, also reduced both hOB proliferation and differentiation. Coincubation with both superoxide dismutase (SOD; 100 U/ml) and catalase (CAT; 50 U/ml), rendering SIN-1 a pure NO* donor, reversed its effects on hOB proliferation and differentiation. However, SIN-1-induced NO* production, measured by nitrite release to the hOB medium, was not altered by cotreatment with SOD and CAT. Expression of nitrotyrosine by hOB, a marker of PN action, was significantly increased after SIN-1 addition, as compared with untreated cells, as revealed by Western blot analysis. Interleukin-1alpha (IL-1alpha) and interferon gamma (IFN-gamma) but not tumor necrosis factor alpha (TNF-alpha) also significantly increased nitrotyrosine expression in these cells. These data show that PN is at least partially responsible for osteoblast derangement by NO* and that cytokines released during inflammatory arthropathies can induce PN production in hOB cells.