Aluminium (Al) is one of the most abundant elements present in the earth's crust. However, Al is highly neurotoxic and can result in the degeneration of nerve cells in the brains of humans and experimental animals. Exposure of experimental animals to Al during the gestation period leads to the impairment of neuromotor maturation and deficits in neurobehaviorial performance among their offspring. Persistent neurological disorders continued in the offspring at dose levels which do not produce any detectable signs of maternal toxicity. Recently, it has been reported that Al modulates the DNA topology (CCG repeats), indicating that the gene mutations induced by Al may be involved in the pathology of neurological disorders. In the present study, we injected 26Al into pregnant rats and measured 26Al incorporation into the fetal tissues by accelerator mass spectrometry to examine the possible involvement of Al in the pathogenesis of neurological disorders and in the mechanisms of mutations. From day 15 to day 19 of gestation, 26AlCl3 was subcutaneously injected into pregnant rats. Considerable amounts of 26Al were detected in the brain, liver, kidneys, and bones of fetuses on gestation day 20 and in newborn rats immediately after birth. In the brains of newborn rats, approximately 39% of the 26Al present in the brain was measured in the nuclear fraction (brain cell nuclei). In the nuclear fraction, about 90% of the total 26Al measured in the nuclear fraction was assayed in the chromatin fraction. The newborn rats were raised by 26Al-free surrogate mother rats after birth. The amounts of 26Al in the tissues of newborn rats decreased remarkably during postnatal development. However, 26Al in the brain could still be detected 730 days after birth. It is concluded that 26Al administered to pregnant rats was transferred to their fetuses through the transplacental passage. High concentrations of 26Al were demonstrated in the fetal brain and considerable amounts of 26Al were bound to the chromatin structure in the brain cell nuclei.
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See more of The 10th International Conference on Accelerator Mass Spectrometry (September 5-10, 2005)