Effects of Crotalus durissus collilineatus venom in the isolated rat kidney

Ophidian accidents caused by the subspecies Crotalus durissus are responsible for high morbity and mortality rates. Acute renal failure is a common complication observed in these accidents. The aim of the present study was to investigate the renal effects promoted by the venom of C. d. collilineatus and its fractions, crotoxin and phospholipase A, C. d. collilineatus (Cdc; 30 mu g mL(-1)), crotoxin (CTX; 10 mu g mL(-1)) and phospholipase A(2) (PLA(2); 10 mu g mL(-1)) were tested in isolated rat kidney. The first 30 min of each experiment were used as an internal control and Cdc or its fractions, CTX and PLA(2) were added to the system after this period. All experiments lasted 120 min. The venom of Cdc decreased perfusion pressure (PP; control(120) = 110.3 +/- 3.69 mmHg; Cdc(120) = 96.7 +/- 8.1 mmHg), renal vascular resistance (RVR; control(120) = 6.42 +/- 0.78 mmHg mL g(-1) min(-1); Cdc(120) = 4.8 +/- 0.56 mmHg/mL g(-1) min(-1)), urinary flow (UF; control(120) = 0.19 +/- 0.03 mL g(-1) min(-1); Cdc(120) = 0.12 +/- 0.01 mL g(-1) min(-1)), and glomerular filtration rate (GFR; control(120) = 0.79 +/- 0.07 mL g(-1) min(-1); Cdc(120) = 0.53 +/- 0.09 mL g(-1) min(-1)), but had no effect on the percent of sodium tubular transport (%TNa+), percent of chloride tubular transport (%TK+) and percent of potassium tubular transport (%TCl-). CTX and PLA(2) reduced the GFR, while UF, PP and RVR remained stable during the full 120 min of perfusion. Crotoxin administration also diminished the %TK+ (control(120) = 69.94 +/- 6.49; CTX120 = 33.28 +/- 4.78) and %TCl- (control(120) = 79.53 +/- 2.67; CTX120 = 64.62 +/- 6.93). PLA(2) reduced the %TK+, but exerted no effect on the %TNa+ or on that of TCl-. In conclusion, the C. d. collilineatus venom altered the renal functional parameters evaluated. We suggest that crotoxin and phospholipase A(2) were involved in this process, since the renal effects observed would be due to the synergistic action of the components of the venom. (c) 2005 Elsevier Ltd. All rights reserved.47326026

Purification and biological effects of C-type lectin isolated from Bothrops insularis venom

Bothrops insularis is a snake from Queimada Grande Island, which is an island located about 20 miles away from the southeastern coast of Brazil. Compared to other Brazilian species of Bothrops, the toxinology of B. insularis is still poorly understood. Its C-type lectin is involved in several biological processes including anticoagulant and platelet-modulating activities. We purified the C-type lectin (BiLec) from Bothrops insularis venom and investigated its effect in the isolated kidney. BiLec was purified after two chromatographic steps; firstly, the whole venom was submitted to an HPLC molecular exclusion chromatography followed by a second purification through affinity chromatography. B. insularis lectin (BiLec) was studied as to its effect on the renal function of isolated perfused rat kidneys with the use of six Wistar rats. The concentration of 10 mu g/mL increased perfusion pressure (PP; control(60) = 108.27 +/- 4.9; BiLec(60) = 112.9 +/- 5.4 mmHg; *p < 0.05) and renal vascular resistance (RVR; control(60)=5.38 +/- 0.51; BiLec(60)=6.01 +/- 0.57 mmHg; *p < 0.05). The urinary flow reduced significantly at 90 and 120min of perfusion (UF; control(120)= 0.160 +/- 0.020; BiLec(120) =0.082 +/- 0.008mL g(-1) min(-1); *p < 0.05). Glomerular filtration rate (GFR; control(120)=0.697 +/- 0.084; BiLec(120)=0.394 +/- 0.063 mL g(-1) min(-1); *p < 0.05) diminished only at 120 min. BiLec did not change the percentage of sodium (TNa+), potassium (TK+) and chloride tubular transport (TCl-). The histological alterations probably reflected direct injury on glomerular and tubular renal cells, as demonstrated by the rise in permeability of glomerular endothelial cells, revealed by the presence of a proteinaccous material in the Bowman space. We postulate that the C-type lectin B. insularis promoted its effects probably through interactions with endothelial cells or through the release of other mediators by tubular, mesangial and endothelial cells. (c) 2006 Elsevier Ltd. All rights reserved.47885986

Purification and biological effects of L-amino acid oxidase isolated from Bothrops insularis venom

Bothrops insularis is a snake from Ilha da Queimada Grande, an island located about 20 miles away from the Southeastern coast of Brazil. Compared with other Brazilian species of Bothrops, the toxinology of R insularis is still poorly understood, and so far, no fraction from this venom with amino acid oxidase activity had been isolated or its biological activity tested. We investigated the biochemical and biological effects of one L-amino acid oxidase enzyme isolated from R insularis snake venom (BiLAO), which was purified using HPLC and sequence grade. We also evaluated the renal effects induced by BiLAO. Chromatographic profile of B. insularis whole venom disclosed seven main fractions (I, II, III, IV, V, VI and VII) and the main LAO enzymatic activity was detected in fraction II. The group treated with BiLAO showed a decrease in perfusion pressure (C-120 = 110.28 +/- 3.69; BiLAO(120) = 82.2 +/- 5.6 mmHg*); renal vascular resistance (C-120 = 5.48 +/- 0.53; BiLAO(120) = 4.12 +/- 0.42 mmHg/mL/g/min), urinary flow (C-120 = 0.160 +/- 0.020; BiLAO(120) = 0.064 +/- 0.012 mL/g/min*), glomerular filtration rate (C-120 = 0.697 +/- 0.084; BiLAO(120) = 0.176 +/- 0.017 mL/g/min*), sodium (C-120 = 79.76 +/- 0.56; BiLAO(120) = 65.39 +/- 6.19%*), potassium (C-120 = 69.94 +/- 6.86; BiLAO(120) = 60.26 +/- 2.24%*) and chloride tubular reabsortion (C-120 = 78.53 +/- 2.33; BiLAO(120) = 64.58 +/- 6.68%*). Acute tubular necrosis foci were observed in the group treated with the LAO fraction of the B. insularis snake venom. Some findings have the same morphological aspect of apoptosis, more evident cortically; otherwise, reversible degenerative phenomena represented by hydropic ballooning with extensive cytoplasmic vacuolization and discontinuity of the cell brush borders in the proximal tubular epithelium were observed; furthermore, necrotic detachment of these cells into the tubular lumina, and increased amount of protein deposits in the distal and proximal tubules were observed. In conclusion, the slowness of blood flow and of glomerular filtration resulted in more time for filtration and tubular reabsorption, with elevation of the total percentage of sodium and chlorine reabsorption. The maintenance of the decrease in glomerular filtration rate would determine the subsequent decreases, which were noticed in these parameters. The necrosis observed was the result of damage cell induced by L-amino acid oxidase isolated from B. insularis venom. (c) 2007 Elsevier Ltd. All rights reserved.51219920