Evaluation of lithium genotoxicity

ABSTRACT

This study was conducted on twenty patients having manic-depressive psychosis and treated by lithium for a period from 1-5 years. Determination of serum lithium level was done to all patients [n=20] using flame photometer. Heparinized venous blood [5ml] was withdrawn from every patient. The following genotoxic assays were performed; assay of sister chromatid exchanges [SCEs] frequencies in cultured human leucocytes and in vivo -in vitro analysis of human karyotype. The genotoxic assays performed on mice included micronucleus test [MNT] and analysis of chromosomal aberrations in mice bone-marrow cells. The present study showed that serum lithium level ranged from 0.37 to 1.07 mEq/L with a mean of 0.77 +/- 0.18 mEq/L. The study revealed a statistically insignificant increase in the frequencies of SCEs in cultured human leucocytes, while a significant in crease of structural chromosomal aberrations was observed in the form of sticky chromosomes, eroded chromosomes, acentric and deletions. In mice, lithium carbonate has a weak clastogenic effect upon mice chromosomes when used in a therapeutic dose, but it has a definite clastogenic effect when administered in a dose more than the therapeutic dose as demonstrated by the significant increase in micronucleated polychromatic erythrocytes and structural chromosomal aberrations. The present study proved the clastogenic potentiality of lithium carbonate