[Experimental study of the mechanism of aluminum-induced bone disease]

The mechanism of aluminum-induced bone disease was studied by experiments in vitro and in rats. After decalcification femur sections were treated with 0.1 M AlCl3 and implanted with control bone matrices into weanling male rats. After 4 or 8 weeks of implantation the tissue values of calcium(Ca), phosphorus(P) and aluminum(Al) were measured. The results showed that both Ca and P values in Al-treated bones were obviously lower than those of the controls (P less than 0.01), Al level in these bones remained considerably high. Histological examination indicated that aluminum deposited diffusely in Al-treated bones, the bone formation rate and mineralization rate markedly decreased, osteoclastic and osteoblastic activities were also inhibited. In collagenase incubation test the bone matrices pretreated with different concentrations of AlCl3 showed different degrees of resistance to digestion of collagenase. It is considered that aluminum forms tight complexes with bone collagen causing cross linkage and destroying the inductive effect in bone matrix, thus leading to aluminum-induced bone disease. Our study also suggests that the usage of chelating agents can remove aluminum from matrix and recover its abilities of bone formation and mineralization.