Effectiveness of a new rutin Cu(II) complex in the prevention of lipid peroxidation and hepatotoxicity in hypercholesterolemic rats.

A new rutin copper(II) complex (R-Cu2) was prepared and characterized by spectroscopic methods and elemental analysis. The effects of rutin and R-Cu2 were evaluated on the prevention of hypercholesterolemia in animals feed with high-cholesterol diet (HCD) for 8 weeks. The animals (n = 5) were neither fed with HCD nor treated (control group), or were treated with vehicle, 10 mg/kg simvastatin, rutin (16 and 160 µmol/kg), and R-Cu2 (16 and 160 µmol/kg) administered orally. Total cholesterol (TC) levels were significantly increased (p < .01) in all HCD groups. In rutin and R-Cu2 groups, it was observed a discrete, but not significant, TC and LDL-induced increase inhibition compared with vehicle-treated group. R-Cu2 treatment significantly decreased (p < .05) plasma triglycerides compared with the vehicle-treated group. All groups receiving treatments maintained the malondialdehyde at normal levels. Serum NO levels were reduced in animals treated with rutin and R-Cu2 compared with the vehicle-treated group. In addition, the results also showed that the groups treated with rutin and R-Cu2 reduced significantly (p < .01), the number of neutrophils and prevented histological changes in all evaluated liver zones. R-Cu2 group maintained the ALT, AST, and ALP enzymes at normal levels. Thus, the effects of R-Cu2 in modulating inflammation and protecting liver damage were confirmed. PRACTICAL APPLICATIONS: Rutin, a plant-derived flavonoid, is one of phenolic compounds well known as a nutraceutical due to its antioxidant and anti-inflammatory properties. Findings of this study demonstrate the effects of both rutin and R-Cu2 in modulating inflammation and protecting liver damage in hypercholesterolemic rats. However, some effects analyzed became more evident in R-Cu2. Thereby, it was shown that the synthesis of a new flavonoid compound (R-Cu2) could be applied as a nutraceutical benefit option to prevent hypercholesterolemia condition.

The soluble guanylyl cyclase activator BAY 60-2770 inhibits murine allergic airways inflammation and human eosinophil chemotaxis.

OBJECTIVES: Activators of soluble guanylyl cyclase (sGC) act preferentially in conditions of enzyme oxidation or haem group removal. This study was designed to investigate the effects of the sGC activator BAY 60-2770 in murine airways inflammation and human eosinophil chemotaxis. METHODS: C57Bl/6 mice treated or not with BAY 60-2770 (1 mg/kg/day, 14 days) were intranasally challenged with ovalbumin (OVA). At 48 h, bronchoalveolar lavage fluid (BALF) was performed, and circulating blood, bone marrow and lungs were obtained. Human eosinophils purified from peripheral blood were used to evaluate the cell chemotaxis. RESULTS: OVA-challenge promoted marked increases in eosinophil number in BAL, lung tissue, circulating blood and bone marrow, all of which were significantly reduced by BAY 60-2770. The IL-4 and IL-5 levels in BALF were significantly reduced by BAY 60-2770. Increased protein expression of iNOS, along with decreases of expression of sGC (α1 and ß1 subunits) and cGMP levels were detected in lung tissue of OVA-challenged mice. BAY 60-2770 fully restored to baseline the iNOS and sGC subunit expressions, and cGMP levels. In human isolated eosinophils, BAY 60-2770 (1-5 µM) had no effects on the cGMP levels and eotaxin-induced chemotaxis; however, prior incubation with ODQ (10 µM) markedly elevated the BAY 60-2770-induced cyclic GMP production, further inhibiting the eosinophil chemotaxis. CONCLUSIONS: BAY 60-2770 reduces airway eosinophilic inflammation and rescue the sGC levels. In human eosinophils under oxidized conditions, BAY 60-2770 elevates the cGMP levels causing cell chemotaxis inhibition. BAY 60-2770 may reveal a novel therapeutic target for asthma treatment.

Pharmacological analysis of hemodynamic responses to Lachesis muta (South American bushmaster) snake venom in anesthetized rats.

In this work, we examined some mechanisms involved in the hypotension caused by Lachesis muta (South American bushmaster) venom in anesthetized rats. Venom (1.5 mg/kg, i.v.) caused immediate hypotension that was maximal after 5 min and gradually returned to baseline over 60 min. Pretreatment of rats with the non-selective nitric oxide synthase (NOS) inhibitor Nω-nitro-L-arginine methyl ester (L-NAME) did not attenuate the early phase of venom-induced hypotension, but abolished the recovery phase and resulted in rapid death; a similar effect was observed with the soluble guanylate cyclase (sGC) inhibitor ODQ. In contrast, the hemodynamic responses to venom were not attenuated by the non-selective NOS inhibitor NG-monomethyl-L-arginine, the inducible NOS inhibitor aminoguanidine, the phosphodiesterase 5 inhibitor sildenafil, the adenylate cyclase (AC) inhibitor SQ-22.536, the non-selective muscarinic receptor antagonist atropine, the bradykinin B2 receptor antagonist HOE-140 and the non-selective cyclooxygenase inhibitor indomethacin. Preincubation of venom with the PLA2 inhibitor pBPB had no effect on the immediate hypotension but tended to improve the recovery phase. Neither AEBSF (a serine proteinase inhibitor) nor EDTA (a metalloproteinase inhibitor) prevented the venom-induced hypotension, but AEBSF and not EDTA protected against the lethality of a high dose (3.0 mg/kg, i.v.). There were no marked changes in the ECG parameters with the various treatments, except with L-NAME and ODQ that increased the RR interval. Pulmonary thrombus formation was markedly enhanced by L-NAME and ODQ, and to a lesser extent by pBPB, especially in small vessels, whereas AEBSF and EDTA inhibited thrombus formation. Venom relaxed phenylephrine-precontracted thoracic aorta and pulmonary artery in vitro, with the latter being more sensitive. The relaxation was endothelium-dependent and was inhibited by ODQ but not by H-89, a protein kinase A (PKA) inhibitor. Together, these findings indicate involvement of the NO/sGC/cGMP, but not the AC/cAMP/PKA signaling pathway, in the hemodynamic responses to L. muta venom in rats. Muscarinic mechanisms, kinins and arachidonic acid metabolites are apparently not involved.

Hemodynamic responses to Lachesis muta (South American bushmaster) snake venom in anesthetized rats.

In this work, we examined the hemodynamic responses to Lachesis muta (South American bushmaster) venom in anesthetized male Wistar rats. Venom (1.5 mg/kg, i.v.) caused immediate hypotension that was followed by a gradual return towards baseline over 60 min; there were no significant changes in heart rate, ECG parameters and respiratory rate. A higher dose (3 mg/kg, i.v.) caused sustained hypotension, variable bradycardia, respiratory depression and fluctuations in ECG; death occurred within 10-60 min. Venom injected intramuscularly (15 mg/kg) produced a smaller decrease in blood pressure that was more persistent than with 1.5 mg/kg (i.v.). Pre-treatment with atenolol (selective ß1-adrenergic receptor antagonist) potentiated the response to venom (1.5 mg/kg, i.v.) and resulted in a hemodynamic profile similar to that seen with 3 mg/kg (i.v.). Macroscopically, systemic hemorrhage was seen only in the ileum, whereas histological analysis revealed extensive pulmonary hemorrhage; the heart, liver and kidney were generally unaffected. Intravascular pulmonary thrombosis occurred with venom given i.v. and i.m., but was less marked with the latter route. In rat isolated perfused hearts, venom caused a persistent decrease in left ventricular developed pressure but no change in heart rate, coronary flow or ECG; there was tissue necrosis and release of CK-MB that were abolished by pre-treating venom with the PLA2 inhibitor p-bromophenacyl bromide. These results show that in rats L. muta venom causes hypotension, bradycardia and respiratory depression, depending on the dose and route of administration. The hemodynamic responses apparently do not involve direct cardiotoxicity and are modulated by the adrenergic system.

Rat atrial responses to Bothrops jararacussu (jararacuçu) snake venom.

Envenoming by the pitviper Bothrops jararacussu produces cardiovascular alterations, including coagulopathy, systemic hemorrhage, hypotension, circulatory shock and renal failure. In this work, we examined the activity of this venom in rat isolated right atria. Incubation with venom (0.025, 0.05, 0.1 and 0.2mg/ml) caused concentration-dependent muscle contracture that was not reversed by washing. Muscle damage was seen histologically and confirmed by quantification of creatine kinase-MB (CK-MB) release. Heating and preincubation of venom with p-bromophenacyl bromide (a phospholipase A2 inhibitor) abolished the venom-induced contracture and muscle damage. In contrast, indomethacin, a non-selective inhibitor of cyclooxygenase, and verapamil, a voltage-gated Ca(2+) channel blocker, did not affect the responses to venom. Preincubation of venom with Bothrops or Bothrops/Crotalus antivenom or the addition of antivenom soon after venom attenuated the venom-induced changes in atrial function and tissue damage. These results indicate that B. jararacussu venom adversely affected rat atrial contractile activity and muscle organization through the action of venom PLA2; these venom-induced alterations were attenuated by antivenom.

Long-term disruption of maternal glucose homeostasis induced by prenatal glucocorticoid treatment correlates with miR-29 upregulation.

Excess of glucocorticoids (GCs) during pregnancy is strongly associated with the programming of glucose intolerance in the offspring. However, the impact of high GC levels on maternal metabolism is not clearly documented. This study aimed to test the hypothesis that mothers exposed to elevated levels of GCs might also display long-term disturbances in glucose homeostasis. Dexamethasone (DEX) was administered noninvasively to the mothers via drinking water between the 14th and the 19th days of pregnancy. Mothers were subjected to glucose and insulin tolerance tests at 1, 2, 3, 6, and 12 mo postweaning. Pregnant rats not treated with DEX and age-matched virgin rats were used as controls. Pancreatic islets were isolated at the 20th day of pregnancy and 12 mo postweaning in order to evaluate glucose-stimulated insulin secretion. The expression of the miR-29 family was also studied due to its responsiveness to GCs and its well-documented role in the regulation of pancreatic ß-cell function. Rats treated with DEX during pregnancy presented long-term glucose intolerance and impaired insulin secretion. These changes correlated with 1) increased expression of miR-29 and its regulator p53, 2) reduced expression of syntaxin-1a, a direct target of miR-29, and 3) altered expression of genes related to cellular senescence. Our data demonstrate that the use of DEX during pregnancy results in deleterious outcomes to the maternal metabolism, hallmarked by reduced insulin secretion and glucose intolerance. This maternal metabolic programming might be a consequence of time-sustained upregulation of miR-29s in maternal pancreatic islets.

Cardiovascular responses to Bothrops alternatus (Urutu) snake venom in anesthetized dogs.

The cardiovascular responses to Bothrops alternatus snake venom in anesthetized dogs were investigated. Venom (0.3 mg/kg, i.v.) markedly decreased arterial blood pressure, coronary perfusion pressure, and cardiac output (CO) after 5 min, with progressive recovery of the first two parameters to pre-venom levels after 3 h; CO showed little recovery. There was an abrupt, sustained decrease in left and right ventricular systolic work and stroke volume but no significant changes in heart rate, electrocardiogram, and pulmonary hemodynamics; systemic vascular resistance increased from 1 h onwards. A venom dose of 1 mg/kg produced more pronounced cardiovascular alterations, with a progressive decrease to death. There were no significant changes in blood gas (pO(2), pCO(2), HCO(3), SBC, and SBE) and metabolic (pH, lactate, glucose, creatine kinase activity, Na(+), and K(+)) parameters, although there was a transitory increase in plasma lactate dehydrogenase 2 min after the lower venom dose. There were no cardiac histological alterations, but microaneurysms and epithelial desquamation were seen in renal tubules. Circulating venom concentrations (determined by ELISA) decreased rapidly after administration, but venom was still detectable after 4 h. These results show that in dogs, B. alternatus venom produces marked hypotension and a direct cardiac action, with few metabolic alterations.

Renal kinetics of Bothrops alternatus (Urutu) snake venom in rats.

The renal kinetics of Bothrops alternatus venom (0.8 mg/kg, i.v.) was studied in conscious male Wistar rats. Blood, urine and renal tissue samples were collected at various intervals after envenoming. Venom was quantified by ELISA in serum, renal tissue and urine. Urine volume was measured and the urine assayed for urobilinogen, glucose, bilirubin, ketones, urine specific gravity, occult blood, pH, protein, nitrite and leucocytes. Circulating venom showed biexponential kinetics, with no venom being detected after 7 days post-venom. Venom was detected in renal tissue 30 min post-venom but decreased progressively thereafter, in parallel with serum venom concentrations. Immunohistochemistry detected venom in glomeruli, proximal and distal tubules, and vascular and perivascular tissue. Venom was detected in urine 3, 6 and 24 h post-venom. Oliguria occurred 3 h to 7 days post-venom, urine acidification occurred 3-6 h post-venom, urine specific gravity increased in the first 3 h and proteinuria was also greatest in this period. Creatinine clearance decreased progressively until 24-48 h post-venom, then returned to normal. Glucose, ketones, leucocytes and occult blood were detected mainly during the first 6 h post-venom. These results indicate reversible alterations in renal function, with renal elimination of the venom.