Estudo dos efeitos renais do veneno da serpente Lachesis muta muta

Abstract

The accident caused by the snake Lachesis muta muta is serious and its venom is responsible for many systemic changes, such as hypotension. In this work, the renal effects of the total venom of this snake in the renal perfusion system and in cultured renal tubular cells of the type MDCK (Madin-Darby Canine Kidney) are investigated. Isolated kidneys from Wistar rats, weighing 250 to 300g, were perfused with previously dialysed, Krebs-Henseleit solution containing 6% w/v bovine albumin. The effects of the venom (10 mg / mL, n = 6) on the perfusion pressure (PP), renal vascular resistance (RVR), urinary flow (UF), glomerular filtration rate (GFR), sodium tubular transport (%TNa+), potassium tubular transport (%TK+) and chloride tubular transport (%TCl-) were submitted to analysis. Lachesis muta muta venom was added to the system after 30 minutes of internal control. MDCK cells were cultured in RPMI 1640 medium supplemented with 10% v/v fetal bovine serum and then assessed in the presence of the total venom of the snake Lachesis muta muta in the concentrations of 1μg/mL, 10μg/mL and 100μg/mL 24 hours afterwards, tests concerning viability and cellular cytotoxicity were brought about. The total venom (10μg/mL) promoted a transient reduction in perfusion pressure (C60= 108.27 ± 4.88; VT L. m. muta60= 88.17 ± 5.27#; C90= 108.69 ± 5.08; VT L. m. muta90= 78.71 ± 6.94#*) and renal vascular resistance (C60= 5.57 ± 0.49; VT L. m. muta60= 3.50 ± 0.22#; C90= 5.32 ± 0.57; VT L. m. muta90= 3.11 ± 0.26#*); increase in urinary flow (C60= 0.158 ± 0.015; VT L. m. muta60= 0.100 ± 0.012#; C120= 0.160 ± 0.020; VT L. m. muta120= 0.777± 0.157#*) and in glomerular filtration rate (C60= 0.707 ± 0.051; VT L. m. muta60= 0.232 ± 0.042#; C120= 0.697 ± 0.084; VT L. m. muta120= 1.478 ± 0.278#*). Such a concentration also reduced significantly sodium tubular transport (%TNa+), potassium tubular transport (%TK+) and chloride tubular transport (%TCl-) in the three periods analyzed (30, 60 and 90 minutes), with a consequent increase in the osmotic clearance (Cosm) (C90= 0.141 ± 0.011; VT L. m. muta90= 0.309 ± 0.090; C120= 0.125 ± 0.016; VT L. m. muta120= 0.839 ± 0,.184#*). Histological analysis of the kidneys perfused with the poison revealed focal areas of renal tubular cells with nuclear pyknosis. The venom also promoted a cytotoxic effect on MDCK cells at concentrations 10μg/mL and 100μg/mL, thus reducing the viability of these cells to 38.60 ± 17.9% and 10.62 ± 2.9%, respectively. These results demonstrate that the venom of Lachesis muta muta altered all the renal parameters assessed in renal perfusion, inducing transient hypotension and intense diuresis. The venom also exhibits cytotoxic activity on MDCK cells after 24 hours of incubation.