RESUMEN
Microcystins (MCYST) are the most frequently reported cyanotoxins in human poisoning incidents. Despite the well-described mechanism of acute and lethal injury, the sublethal effects of this toxin require further investigation. The aim of this study was to contribute to the knowledge of the variant MCYST-LR effects at sublethal doses by investigating biochemical changes and tissue damage in a murine model. For this purpose, mice were intraperitoneally injected with 45 µg of MCYST-LR/kg body weight. Their organs were collected at 2, 8, 24, 48 or 96 h after injection. Control animals received saline solution. We detected oxidative imbalance in the liver, particularly at 8 h after exposure. Furthermore, biomarkers of liver injury were detected in high concentration in the serum of the exposed animals. Stereological analyses of the liver indicated two different phases in the intoxication process: an initial phase characterized by an increase in steatosis was followed by a second, later phase characterized by increased inflammation and hepatocyte binucleation. Formation of areas of necrosis and increased blood vessel diameter were observed throughout the experimental period. The number of hepatocytes per area unit also decreased. However, these parameters recovered over the period of exposure. MCYST accumulated in liver and was detectable until the end of the monitoring period. These results confirm the necessity for further studies of processes involved in sublethal exposure to MCYST.
Asunto(s)
Hígado/efectos de los fármacos , Microcistinas/toxicidad , Animales , Hepatocitos/efectos de los fármacos , Hepatocitos/patología , Hígado/patología , Masculino , Toxinas Marinas , Ratones , Necrosis/inducido químicamente , Oxidación-Reducción , Pruebas de ToxicidadRESUMEN
Cylindrospermopsin is a cyanobacterial toxin of increasing environmental importance, as it can lead to disease if orally or intravenously absorbed. However, its in vivo lung impairment has not been documented. Thus, we aimed at verifying whether cylindrospermopsin can induce lung injury and establish its putative dependence on the time elapsed since exposure. BALB/c mice were intratracheally injected with either saline (NaCl 0.9%, 50 µL, SAL group, n = 12) or a sublethal dose (70 µg/kg) of semi-purified extract of cylindrospermopsin (CYN groups, n = 52). Lung mechanics, histological and biochemical analyses, and cylindrospermopsin presence in lungs and liver were determined in independent groups at 2, 8, 24, 48, and 96 h after cylindrospermopsin instillation. There was a significant increase in static elastance at 24 and 48 h after exposure to cylindrospermopsin, while viscoelastic component of elastance and viscoelastic pressure rose at 48 h. Alveolar collapse augmented in CYN groups at 8 h. A significant increase in polymorphonuclear influx into lung parenchyma, as well as a higher myeloperoxidase activity started off at 24 h. Exposure to cylindrospermopsin increased lipid peroxidation and superoxide dismutase activity and reduced catalase activity in CYN groups. The toxin was detected in lungs and liver of all CYN mice. In conclusion, cylindrospermopsin exposure impaired lung mechanics, which was preceded by lung parenchyma inflammation and oxidative stress.
Asunto(s)
Cianobacterias/química , Pulmón/efectos de los fármacos , Mecánica Respiratoria/efectos de los fármacos , Uracilo/análogos & derivados , Alcaloides , Análisis de Varianza , Animales , Toxinas Bacterianas , Catalasa/metabolismo , Toxinas de Cianobacterias , Peroxidación de Lípido/efectos de los fármacos , Hígado/metabolismo , Pulmón/metabolismo , Pulmón/patología , Ratones , Ratones Endogámicos BALB C , Pruebas de Función Respiratoria , Superóxido Dismutasa/metabolismo , Factores de Tiempo , Uracilo/administración & dosificación , Uracilo/toxicidadRESUMEN
Air pollution is associated with morbidity and mortality induced by respiratory diseases. However, the mechanisms therein involved are not yet fully clarified. Thus, we tested the hypothesis that a single acute exposure to low doses of fine particulate matter (PM2.5) may induce functional and histological lung changes and unchain inflammatory and oxidative stress processes. PM2.5 was collected from the urban area of São Paulo city during 24 h and underwent analysis for elements and polycyclic aromatic hydrocarbon contents. Forty-six male BALB/c mice received intranasal instillation of 30 µL of saline (CTRL) or PM2.5 at 5 or 15 µg in 30 µL of saline (P5 and P15, respectively). Twenty-four hours later, lung mechanics were determined. Lungs were then prepared for histological and biochemical analysis. P15 group showed significantly increased lung impedance and alveolar collapse, as well as lung tissue inflammation, oxidative stress and damage. P5 presented values between CTRL and P15: higher mechanical impedance and inflammation than CTRL, but lower inflammation and oxidative stress than P15. In conclusion, acute exposure to low doses of fine PM induced lung inflammation, oxidative stress and worsened lung impedance and histology in a dose-dependent pattern in mice.
Asunto(s)
Lesión Pulmonar/inducido químicamente , Pulmón/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Material Particulado/toxicidad , Animales , Ciudades , Relación Dosis-Respuesta a Droga , Disulfuro de Glutatión/metabolismo , Pulmón/metabolismo , Pulmón/patología , Lesión Pulmonar/metabolismo , Lesión Pulmonar/fisiopatología , Masculino , Ratones , Ratones Endogámicos BALB C , Oxidorreductasas/metabolismo , Tamaño de la Partícula , Material Particulado/química , Pruebas de Función RespiratoriaRESUMEN
The meniscotibial ligaments (LMT) of humans are capsular fibers with proximal origin in the lateral border of the menisci and distal insertion in the lateral border of the tibial condyle, also called coronary ligament of the knee. However, few studies describe the presence, course and anatomical variations of this ligament. Our objective was to evaluate the LMT through quantitative and descriptive methods. Eighty-five knees were examined(42 right knees [RK] and 43 left knees [LK]), dissected, evaluated, catalogued and photographed by four examiners. Twenty knees (23.53%) presented LMT, 6 (30%) in RK and 14 (70%) in LK. In two RKs, the LMT presented proximal insertion in the medial menisci and distal insertion in medial tibial condyle; in the other ones, the LMT presented proximal insertion in the lateral menisci and distal insertion in the lateral tibial condyle. In the LK, four LMT presented proximal insertion in the medial menisci and distal insertion in the medial tibial condyle, while the other ones presented proximal insertion in the lateral menisci and distal insertionin the lateral tibial condyle. One LMT in the LK presented proximal and distal insertion in both menisci and tibial condyle. The analysis of human corpses in our study suggests that the presence of the LMT is much more common in the LK than in the RK, with more frequent insertion in the proximal region of the lateral menisci and distal insertion in the lateral tibial condyle.