We previously showed that plants from the genus Sinningia are a source of antiinflammatory and analgesic compounds with different mechanisms of action. The present study evaluated the antiinflammatory, antinociceptive, and antipyretic effects of a crude extract (CE) from Sinningia canescens, its fractions, and 6-methoxy-7-hydroxy-α-dunnione (MHD) in mice. These effects were evaluated using carrageenan (Cg)-induced paw edema, acetic acid- and formalin-induced nociception, mechanical hyperalgesia, lipopolysaccharide (LPS)-induced fever, and plasma cytokine levels. The CE and dichloromethane and hexane fractions reduced Cg-induced paw edema and hyperalgesia, LPS-induced fever, and plasma tumor necrosis factor-α (TNF-α) levels. The CE also reduced acetic acid-induced writhing and the second phase of formalin-induced nociception but did not alter thermal nociception or motor performance. Partition with solvents showed that the antiinflammatory, antihyperalgesic, and antipyretic activities were present in dichoromethane and hexane fractions, and the major compound isolated from these fractions was MHD. Oral and intraplantar MHD administration reduced paw edema. Oral MHD administration also reduced prostaglandin E-induced hyperalgesia but did not alter hyperalgesia that was induced by dopamine and dibutyryl cyclic adenosine monophosphate. Treatment with glibenclamide, a K channel blocker, did not alter the analgesic effect of MHD. Lipopolysaccharide-induced fever and TNF-α, interleukin-1β, and interleukin-6 levels were inhibited by MHD. Altogether, these data suggest that the CE has antiinflammatory, analgesic, and antipyretic activity, and these actions are at least partially related to MHD. These results also suggest that MHD acts by blocking cytokine synthesis and/or blocking prostaglandin activity.
The present study evaluated the effects of acute treatment with silymarin, an extract that is obtained from Silybum marianum, on angiogenesis, oxidative stress, and inflammation in normoglycemic and diabetic mice. Diabetes was induced by streptozotocin (80 mg/kg, intraperitoneal) in male Swiss mice, 6 weeks of age. A polyether-polyurethane sponge was surgically implanted in the back of the mice as a model of healing in both diabetic and normoglycemic animals that were treated with oral silymarin or water for 10 days. The pancreas, liver, kidneys, blood, and sponges were collected and analyzed. Diabetes led to impairments of antioxidant defenses, reflected by a reduction of pancreatic superoxide dismutase and hepatic and renal catalase and an increase in pancreatic lipoperoxidation. An inflammatory process was observed in diabetic mice, reflected by an increase in pancreatic tumor necrosis factor α (TNF-α) and the infiltration of inflammatory cells in islets. The number of vessels was lower in the implanted sponges in diabetic mice. Silymarin treatment attenuated this damage, restoring antioxidant enzymes and reducing pancreatic TNF-α and inflammatory infiltration. However, silymarin treatment did not restore angiogenesis or glycemia. In conclusion, treatment with silymarin red uced oxidative stress and inflammation that were induced in the model of streptozotocin-induced diabetes in several organs, without apparent toxicity. Silymarin may be a promising drug for controlling diabetic complications.
We previously reported that endothelin-1 (ET-1) reduced the frequency of spontaneous excitatory currents in vasopressinergic magnocellular cells through the activation of endothelin ETA receptors in rat brain slices. This effect was abolished by a cannabinoid CB1 receptor antagonist, suggesting the involvement of endocannabinoids. The present study investigated whether the blockade of ETA or CB1 receptors during the phase of increased levels of ET-1 after severe sepsis increases the survival rate of animals concomitantly with an increase in plasma arginine vasopressin (AVP) levels. Sepsis was induced in male Wistar rats by cecal ligation and puncture (CLP). Treatment with the CB1 receptor antagonist rimonabant (Rim; 10 and 20 mg/kg, orally) 4 h after CLP (three punctures) significantly increased the survival rate compared with the CLP per vehicle group. Intracerebroventricular treatment with the ETA receptor antagonist BQ123 (100 pmol) or with Rim (2 μg) 4 and 8 h after CLP but not the ETB receptor antagonist BQ788 (100 pmol), also significantly improved the survival rate. Sham-operated and CLP animals that were treated with Rim had significantly lower core temperature than CLP animals. However, oral treatment with Rim did not change bacterial count in the peritoneal exudate, neutrophil migration to the peritoneal cavity, leucopenia or increased plasma interleukin-6 levels induced by CLP. Both Rim and BQ123 also increased AVP levels 12 h after CLP. The blockade of central CB1 and ETA receptors in the late phase of sepsis increased the survival rate, reduced body temperature and increased the circulating AVP levels.
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