In-vitro Aluminium Uptake by the Bone and its Effect on Bone Mineral

In-vitro aluminium uptake by the bone and its effect on bone mineral has been studied at different Al3+ concentrations viz., 500, 1000, 1500, 2000, 2500 and 3000 ppm and for different time periods viz., 30 and 60 days. Leg bone of goat was used for the study. Results revealed that Al uptake by the bone is concentration dependent as well as time dependent. In 30 days, the aluminium uptake varied from 0.66 to 3.25 mg/g, and in 60 days, it varied from 1.19 to 5.48 mg/g, depending on Al3+ concentration (500 to 3000ppm) of the milieu. X-ray diffraction studies of experimental (Al exposed) and control (without Al exposure) samples of bone powders reveal a change in position (2Ï´) and d-spacings of the peaks of calcium hydroxylapatite mineral of the bone by Al exposure. X-ray diffraction pattern of synthetic calcium hydroxylapatite, prepared in the absence and presence of Al3+ also revealed similar changes brought about by aluminium. The infrared (FTIR) spectra of experimental and control bone powders revealed a change in the position of symmetric and asymmetric P-O stretching vibrations of phosphate bands by Al exposure. Similar changes in P-O bands were also observed on comparing the infrared spectra of synthetic calcium hydroxylapatite prepared in the absence and presence of aluminium. Thus, it seems aluminium, uptaken by the bone, disturbs the mode of phosphate bonding in the calcium hydroxylapatite mineral of the bone and thus, distorts its usual crystal structure. This might be the chemical mechanism behind aluminium osteotoxicity.

Author(s): TVRK Rao and Arjun Kumar

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