Inflammatory effect of aluminium phosphate on rat paws.

The aim of this experiment was to determine the inflammatory effect of aluminium phosphate on the rat paw and to compare it with those of carrageenan, calcium hydrogen phosphate dihydrate and natural diamond powder. At the probability threshold of the various tests used there was a significant increase in volume of the treated paw relative to the control paw for all the substances at all times, except for the two concentrations of diamond (effect no longer significant from 30 min on), of calcium phosphate (not significant from 2 h), and of aluminium phosphate (not significant from 24 h). The effects were not significantly different between diamond and calcium phosphate (both concentrations). The effects of aluminium phosphate were significantly different from those of the two until at least 2 h after the injection ; there was no significant difference between the two doses of this substance. The kinetics of the effects produced by carrageenan differed from the kinetics of the other materials, its effects were not significantly different from those produced by aluminium phosphate until 2 h and later. The inflammatory effect that we have demonstrated in this study is added information suggesting that in addition to apatite, calcium pyrophosphate dihydrate, and sodium monourate, aluminium compounds can play a role in the unexpected appearance of inflammatory manifestations in haemodialysed patients with chronic renal insufficiency treated with aluminium gels.