Renal effects of supernatant from macrophages activated by Crotalus durissus cascavella venom: the role of phospholipase A2 and cyclooxygenase.
ABSTRACT In Brazil, the genus Crotalus is responsible for approximately 1500 cases of snakebite annually. The most common complication in the lethal cases is acute renal failure, although the mechanisms of the damaging effects are not totally understood. In this work, we have examined the renal effects caused by a supernatant of macrophages stimulated by Crotalus durissus cascavella venom as well the potential role of phospholipase A2 and cyclo-oxygenase. Rat peritoneal macrophages were collected and placed in a RPMI medium and stimulated by crude Crotalus durissus cascavella venom (1, 3 or 10 microg/ml) for 1 hr. They were then washed and kept in a culture for 2 hr. The supernatant (1 ml) was tested in an isolated perfused rat kidney. The first 30 min. of each experiment were used as an internal control, and the supernatant was added to the system after this period. All experiments lasted 120 min. A study of toxic effect on perfusion pressure, glomerular filtration rate, urinary flow percent of sodium tubular transport and percent of proximal tubular sodium transport was made. The lowest concentration of venom (1 microg/ml) was not statistically different from the control values. The most intense effects were seen at 10 microg/ml for all renal parameters. The infusion of the supernatant of macrophages stimulated with crude venom (3 or 10 microg/ml) increased the perfusion pressure, glomerular filtration rate and urinary flow, decreased the percent of sodium tubular transport and percent of proximal tubular sodium transport. Dexamethasone (10 microM) and quinacrine (10 microM) provided protection against the effect of the venom on glomerular filtration rate, urinary flow, percent of sodium tubular transport, percent of proximal tubular sodium transport and perfusion pressure. Indomethacin (10 microM) and nordiidroguaretic acid (1 microM) reversed almost all functional changes, except those of the perfusion pressure. These results suggest that macrophages stimulated with Crotalus durissus cascavella venom release mediators capable of promoting nephrotoxicity in vitro. Moreover, phospholipase A2 and cyclooxygenase products are involved in these biologic effects.
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ABSTRACT: Karla PO Luna1,2, Cristiane ML Melo1, Vanessa P Magalhães3, Olindo A Martins-Filho3, Valéria RA Pereira11Departamento de Imunologia, Instituto Aggeu Magalhães – FIOCRUZ, Pernambuco, Brazil; 2Universidade Estadual da Paraíba, Campina Grande, Brazil; 3Centro de Pesquisas René Rachou – FIOCRUZ, Minas Gerais, BrazilAbstract: Snake venom is a complex biological mixture used for immobilization and killing of prey for alimentation. Many effects are inflicted by this venom, such as coagulation, necrosis, bleeding, inflammation, and shock. This study aimed to evaluate the inflammatory activity promoted by Bothrops erythromelas and Crotalus durissus cascavella snake venom. It was observed that both B. erythromelas and C. d. cascavella venom induced higher interferon-gamma and interleukin-6 production. Nitric oxide (NO) was significantly produced only by B. erythromelas venom, which also showed a higher rate of cell death induction when compared with C. d. cascavella. Results showed that B. erythromelas and C. d. cascavella venom induced distinct response in vitro through cytokines and NO production. However, B. erythromelas induces a proinflammatory response and a higher rate of cell death in relation to C. d. cascavella venom.Keywords: snake venom, Bothrops, nitric oxide, necrosis, CrotalusInternational Journal of Interferon, Cytokine and Mediator Research. 01/2011;
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ABSTRACT: In this study, we investigated in groups of female BALB/c mice injected with Crotalus durissus terrificus venom (Cdt) the renal function based on creatinine clearance, percentage of fractional excretion cytokines and histological examination of renal tissue. Cdt caused renal alterations that induced proteinuria during the initial hours post-venom and reduced creatinine clearance 15 min. up to 2 hours post-venom administration. In urine from mice injected with Cdt induced a decrease in IL-4 levels. More pronounced increments of IL-5, IL-6 and IFN-γ were observed after 15 and 30 min, respectively. The highest levels of TNF and IL-10 were observed at 1 and 4 hs, respectively. The ratios of pro- and anti-inflammatory cytokines in animals injected with Cdt, which may be manifested in the inflammatory status during the envenoming. In groups of animals treated with Cdt were observed a decreasing in creatinine clearance and its effect on glomerular filtration rate was accompanied by decreased fractional excretion of cytokines and morphologic disturbances. This loss of change selectively in envenomation could thus explain why the relatively excretion of cytokines is reduced while of total proteins increases. In conclusion the fractional excretion of cytokines is significantly reduced in mice injected with Cdt, despite proteinuria.Mediators of Inflammation 01/2011; 2011:103193. · 3.88 Impact Factor
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ABSTRACT: Crotalus durissus cascavella is a snake that is usually found in the scrublands of northeast Brazil. The components of its venom may have effects on the vascular and renal systems. Recently, a new bradykinin inhibitory peptide has been identified in the venom of the Crotalinae family. The aim of the present study was to investigate the renal and vascular effects of the natriuretic peptide isolated from the venom of Crotalus durissus cascavella (NP2_Casca). The chromatographic profile showed the fractionation of substances identified as convulxin, gyroxin, crotoxin and crotamine, as well as fractions V and VI. The electrophoretic profile of fraction V consisted of several bands ranging from approximately 6 kDa to 13 kDa, while fraction VI showed only two main electrophoretic bands with molecular weights of approximately 6 and 14 kDa. Reverse-phase chromatography showed that NP2_Casca corresponds to about 18% of fraction VI and that this fraction is the main natriuretic peptide. NP2_Casca was compared to other natriuretic peptides from other sources of snake venom. All amino acid sequences that were compared showed a consensus region of XGCFGX, XLDRIX and XSGLGCX. The group treated with NP2_Casca showed an increase in perfusion pressure, renal vascular resistance, urinary flow and glomerular filtration rate. The percent of total and proximal tubular transport of sodium was reduced significantly after administration of the peptide. The mean arterial pressure showed a dose-dependent decrease after infusion of NP2_Casca, and an increase in nitrite production. In the aortic ring assay, NP2_Casca caused a relaxant effect in endothelium-intact thoracic aortic rings precontracted with phenylephrine in the presence and absence of isatin. NP2_Casca failed to relax the aortic rings precontracted with an isosmotic potassium Krebs–Henseleit solution. In conclusion, the natriuretic peptide isolated from Crotalus durissus cascavella venom produced renal and vascular effects. NP2_Casca reduced total and proximal sodium tubular transport, leading to an increase in sodium excretion, thereby demonstrating a diuretic action. A hypotensive effect was displayed in an arterial pressure assay, with an increase in nitrite production, suggesting a possible vasoactive action.Toxicon 10/2008; · 2.92 Impact Factor