In vivo effect of aluminium upon the physical properties of the erythrocyte membrane

Aluminium (Al (III)) is a metal with no biological function. Its organic accumulation can lead to toxic effects. To elucidate the in vivo effect of Al (III) upon the rheological properties of the erythrocyte membrane, male adult Wistar rats have been submitted to periodical injections of Al(OH)3 during three months. Significant decreases in haematocrit (34 ± 0.37% versus 36 ± 0.20%, p < 0.0001) and blood haemoglobin concentration (10.7 ± 0.15 g/dl versus 12.3 ± 0.49 g/dl, p < 0.005) have been found. Haemolysis curves shifted towards the left, indicating that erythrocytes became more resistant to hypotonic haemolysis. Significant increments in rigidity index (29.6 ± 1.59 versus 9.2 ± 0.40, p < 0.0001), relative viscosity at native haematocrit (3.6 ± 0.03 versus 3.5 ± 0.03, p < 0.04), and relative viscosity at standard haematocrit (4.5 ± 0.06 versus 3.9 ± 0.05, p < 0.0001) have been observed. The decrease in the erythrocyte aggregate size (1.6 ± 0.01 versus 1.7 ± 0.01, p < 0.002) and the aggregation rate (0.5 ± 0.02 versus 0.6 ± 0.03, p < 0.002) indicated a significantly dropped aggregability process. In conclusion, Al (III) disorganised the erythrocyte membrane by altering its mechanical properties, suggesting a reduction of the middle life of circulating erythrocytes, which could play a major role in the anaemia of these animals.