RESUMEN
BACKGROUND: Rheumatoid arthritis (RA) is associated with a high concentration of extracellular DNA (ecDNA). This could be a consequence of the inflammation, but the ecDNA could also be involved in the unknown etiopathogenesis of RA. Clearance of ecDNA is hypothesized to prevent the development of RA. This study aimed to analyze the effects of exogenous deoxyribonuclease I (DNase I) administration in an animal model of RA. METHODS: The collagen antibody-induced arthritis (CAIA) model of RA was induced in adult female DBA/1J mice. CAIA mice were treated with saline or DNase I (10 mg/kg) every 12 h for the whole duration of the experiment. Arthritic scores were assessed. Paw volume and temperature were assessed using a plethysmometer and a thermal camera, respectively. Plasma ecDNA and its subcellular origin were analyzed using fluorometry and real-time PCR. DNase activity was quantified with single radial enzyme diffusion method. RESULTS: The CAIA model was successfully induced as proved by a higher volume, temperature and the overall arthritis score in comparison to controls. The administration of DNase I resulted in a nearly two-fold increase in serum DNase activity. Still, it did affect neither plasma ecDNA, nor the arthritis score or other measures of joint inflammation. CONCLUSION: Our results suggest that exogenous DNase I does not prevent the development of CAIA in mice. Whether this is true for other animal models of arthritis or clinical RA requires further research. EcDNA does not seem to be involved in the pathogenesis of CAIA. Additional studies are also needed to elucidate the role of ecDNA in the development of RA, focusing especially on its origin and inhibition of ecDNA release.
RESUMEN
INTRODUCTION: The most common suicide methods vary slightly from country to country, partly related to the availability of effective means. Societal development over the years and especially the advent of the Internet has enabled the sudden spread of new suicide methods. Recently, especially since 2019, intentional sodium nitrite poisoning has appeared on many social networks as an increasingly popular method of suicide. MATERIAL AND METHODS: There was performed a retrospective-prospective study of the autopsy protocols of the Medico-Legal Departments of the Healthcare Surveillance Authority in Slovakia, in a period of 15 years (2008-2022). We performed the analysis of cases of death due to nitrite poisoning, focusing on cases of intentional self-harm. In all selected cases, we present complete information, including photo documentation from the place of death, as well as the results of the performed autopsy and the results of additional laboratory examinations. RESULTS: We did not record any fatal cases of unintentional, accidental consumption of sodium nitrite in Slovakia, nor any fatal cases of homicidal poisoning by this substance. However, there were three cases of intentional self-harm (completed suicide) by sodium nitrite poisoning (in 2019, 2020 and 2022). CONCLUSIONS: The correct diagnosis of the cases of sodium nitrite poisoning deaths is possible only based on evaluating all the information obtained, a thorough examination of the body and the crime scene, and the correct interpretation of the findings found during a subsequent autopsy and the results of the toxicological analysis.