The effects of silymarin plus glutathione on the prevention of liver ischemia-reperfusion injury

Abstract Liver ischemia-reperfusion (IR) injury is a major clinical trouble encountered in clinical practice. This study aimed to examine the therapeutic effects of silymarin (SM) plus glutathione (GSH) on hepatic IR injury using a rat model of liver IR. Fifty male rats were randomly divided into five groups, each consisting of 10 rats as follows: Sham, IR, SM-IR, GSH-IR and SM plus GSH-IR. All groups except sham were subjected to 30-min ischemia and 24-h reperfusion. The treated groups received 100 mg/kg of SM, GSH and a mixture of SM plus GSH, 60 min prior to the IR. After a period of 24 h, blood and liver samples were collected for biochemical and histopathological evaluations. Pretreatment with SM, GSH and SM plus GSH before hepatic IR significantly decreased IR-induced elevations of aminotransferases, and significantly reduced the histopathological damage scores of the liver in the late phase of IR injury. Moreover, SM plus GSH treatment prior to liver IR significantly suppressed inflammatory process and oxidative stress as demonstrated by attenuations in tumor necrosis factor-α, myeloperoxidase and the thiobarbituric acid-reactive substances. These findings suggest that administration of SM plus GSH prior to liver IR may protect the liver parenchyma from the effects of an IR injury

Detecção de Espécies Reativas de Oxigênio no sangue periférico de pacientes com leptospirose grave / Detection of Reactive Oxygen Species in peripheral blood patients with severe leptospirosis

Leptospirose é uma zoonose que pode levar a graves complicações, como a síndrome de Weil e a síndrome pulmonar hemorrágica, porém os mecanismos patogênicos que levam ao desenvolvimento das formas graves da doença ainda são desconhecidos. Após a penetração no indivíduo, as leptospiras invadem a corrente sanguínea e se disseminam para os órgãos. Dessa forma, a leptospirose apresenta características semelhantes as da sepse, doença que tem o estresse oxidativo como um dos principais responsáveis pelo seu agravamento. Entretanto, pouco se sabe sobre o envolvimento do estresse oxidativo na leptospirose. O presente estudo teve como objetivo avaliar se a produção de espécies reativas de oxigênio (ROS) e os níveis do antioxidante glutationa (GSH) estão relacionados com as manifestações clínicas mais graves de pacientes hospitalizados com leptospirose. A produção de ROS e os níveis de GSH foram avaliados nas amostras de sangue de doze pacientes e nove indivíduos saudáveis através dos ensaios de quimioluminescência e de absorbância, respectivamente. Nós observamos que os níveis de ROS estavam aumentados (p=0.0012) e os de GSH diminuídos (p=0.0002) nos pacientes quando comparados com os indivíduos saudáveis. Dentre os pacientes, a diminuição de GSH estava correlacionada com a trombocitopenia (r=0.63) e com elevados níveis de creatinina (r= -0.64), enquanto que a produção de ROS estava fortemente correlacionada com os níveis elevados de potássio sérico (r=0.8). A compreensão da importância biológica de ROS e do GSH na leptospirose faz-se necessária, pois uma investigação mais detalhada pode levar ao desenvolvimento de terapias adjuvantes focadas no estresse oxidativo.

Leptospirosis is a zoonotic disease that causes severe manifestations such as Weil’s disease and pulmonary hemorrhage syndrome, however the underlying mechanisms that lead to the development of severe forms are not clear. Leptospires penetrate through skin, reach the bloodstream and disseminate to the organs. Thus, leptospirosis and sepsis have similar characteristics. Although there is vast literature demonstrating that oxidative stress play an important role in the severity of sepsis, none is known about it in leptospirosis. The aim of this study was to evaluate whether reactive oxygen species (ROS) production and antioxidant reduced glutathione (GSH) levels are related to complications in patients hospitalized with leptospirosis. ROS production and GSH levels were measured in blood samples of twelve patients and nine healthy controls using chemiluminescence and absorbance assays. We found that ROS production was higher (p=0.0012) and GSH levels were lower (p=0.0002) in leptospirosis patients compared with healthy individuals. Among patients, GSH depletion was correlated with thrombocytopenia (r=0.63) and elevated serum creatinine (r= -0.64), while a strong positive correlation was observed between ROS production and elevated serum potassium (r=0.8). Additional investigation of the biological significance of ROS production and GSH levels is warranted as they may guide the development of novel adjuvant therapies for leptospirosis targeting oxidative stress.

Influence of diabetes mellitus on the glutathione redox system of human red blood cells

Several components of the erythrocyte-dependent glutathione redox system (reduced glutathione, GSH; oxidized glutathione, GSSG; glutathione peroxidase, GSH-Px; glutathione reductase, GSH-Red) were determined in patients with types I and II diabetes mellitus (DM). All groups studied were male subjects: G1, 200 young healthy individuals (aged 23.7 ñ 4.2 years); G2, 15 young insulin-treated type I DM patients; G3, 20 older older insulin-treated type II DM patiens; G4, 21 older oral hypoglycemic agent-treated type II DM patients; G5, 28 aged healthy individuals (aged 68.9 ñ 11.5 years). There were no differences between G1 and G3 or G4 regarding erythrocyte GSH, GSSG, and GSH-Red (without FAD) levels. GSH-Px activity was significantly lower in G2 when compared to G1 (15.2 ñ 4.9 vs 20.6 ñ 6.6 IU/g Hb). The GSH-Red and GSH-Px activities and GSH levels were significantly higher in G3 (4.6 ñ 1.7 IU/g Hb, 20.2 ñ 8.7 IU/g Hb and 3.5 ñ 1.3 uM/g Hb) and G4 (5.0 ñ 2.2 IU/g Hb, 16.9 ñ 6.1 IU/g Hb and 5.0 ñ 2.3 uM/g Hb) when compared to G5 (3.4 ñ 0.9 IU/g Hb, 12.0 ñ 3.6 IU/g Hb and 2.3 ñ 0.9 uM/g Hb). The findings suggest that treatment of DM can stimulate the redox activity of red blood cells in aged subjects