Red Blood Cell Osmotic Fragility in Bufo arenarum Exposed to Lead

Abstract

The effects on red blood cells of a single sublethal dose of Pb of 100 mg kg-1 administrated to adult Bufo arenarum were studied. The blood d-aminolevulinic acid dehydratase (d-ALAD) activity, the red blood cell (RBC) osmotic fragility (OF), and the hematocrit (Hct) were measured in control and lead poisoned toad. The enzyme d-ALAD is considered as a specific biomarker for human and animals lead exposure. In Bufo, lead also provoked a significant decrease in the d-ALAD activity without changes in the Hct. OF test was used to compare the impact of Pb on the extent of the RBC hemolysis produced by osmotic stress. Experimental data (absorbance of solubilized hemoglobin and [NaCl]) were fitted to the Orcutt et al. equation (1995) that allows a precise characterization of the parameters involved in OF. In blood from injected toads, the OF resulted significantly reduced. These changes were interpreted as a consequence of alterations in the composition and conformation of the RBC membrane due to Pb, as it was described for human erythrocytes.

Assessment of Lead Ecotoxicity in Water using the Amphibian Larvae (Xenopus laevis) and Preliminary Study of its Immobilization in Meat and Bone Meal Combustion Residues

“…Similar observations were reported in tadpoles where the number of red cells diminished after exposure to the metal (Barret 1947). Lead is well known to act on hematopoiesis in amphibians Arrieta et al 2000;Rosenberg et al 1998Rosenberg et al , 2002 and elevated blood lead concentrations may be reflected in alterations of the morphology and the physiological properties of the circulating cells (Rosenberg et al 2003). Lead is also known to alter red blood cell membrane proteins in humans (Caspers & Siegel 1980) and to produce reactive oxygen species involved in the phagocytic process as a consequence of altered membrane integrity, permeability and lipid peroxidation mechanisms (Gurer & Ercal 2000).…”

Long-Term Toxicity Effects of Cadmium and Lead on Bufo raddei Tadpoles

“…Lefcort et al (1998) reported that heavy metals could alter the survival, growth, metamorphosis and antipredatory behavior of Rana luteiventris tadpoles. Rosenberg et al (1998) studied the sublethal effect of lead on erythrocyte osmotic fragility in Bufo arenarum. Naab et al (2001) reported that Zn could inhibit the pentose phosphate pathway in the ovaries of adult B. arenarum females, resulting in a decrease of the embryo survival ratio.…”

Alteraciones bioquímicas, hematológicas y de distribución y acumulación de plomo en un modelo animal y en humanos

“…La actividad de la ALAD se determinó por duplicado de acuerdo a la técnica desarrollada en nuestro laboratorio, basada en el método Europeo Estandarizado (Berlin y Schaller, 1974;Perí et al, 1998). Los principales cambios introducidos en el ensayo consisten en el volumen de sangre utilizada y el pH de la reacción.…”

“…En otra serie de estudios previos, se demostró que la administración del metal en un corto período de tiempo (dosis única de AcPb), no provocaba cambios significantes en el hematocrito (Arrieta et al 2000;Perí et al 1998b;Rosemberg et al, 1998). Ireland (1977) obtuvo resultados coincidentes con éstos en Xenopus leavis adultos, evaluando hemoglobina, hematocrito y reticulocitos, los cuales no presentaron cambios significativos, con excepción de la actividad de la δ-ALAD que tuvo cambios con significancia estadística.…”

“…La DL 50 fue inicialmente estudiada para Rhinella arenarum por Arrieta et al (1999) para las temperaturas 20 y 28, 5ºC. Se adaptó una técnica para ALAD en nuestro laboratorio, basada en el método europeo de Berlin y Schaller (Perí et al, 1998). Al igual que en humanos, en Rhinella arenarum se han encontrado correlaciones entre la plombemia y la disminución de la ALAD (Perí et al, 1998) y el aumento de la Protoporfirina (Arrieta et al, 2003) así como también la alteración de parámetros hematológicos (Perí et al, 1998).…”