protective effect of black seed [Nigella sativa] against carbon tetrachloride-induced chromosomal aberrations and ultrastructural changes of bone marrow cells

The effect of the oral administration of aqueous suspension of Nigella sativa [50 mg/kg b.wt.] against chromosomal aberrations and ultrastructural changes of the bone marrow cells in mice treated with carbon tetrachloride CCl[4] was studied. CCl[4] was administered in two dose levels equivalent to[1/4] [1.9 ml/kg b.wt.] and [1/2] [3.8 ml/kg b.wt.] of the oral LD[50] in mice. The data indicated a significant dose-dependent decrease in the mitotic activity of bone marrow cells in animals treated with CCl[4]. Also a significant dose-dependent increase in the number of bone marrow cells with different types of chromosomal aberrations was recorded in these animals. Ultrastructural changes were also dose-dependent including both nucleus and cytoplasm of erythroid and myeloid elements of the bone marrow cells. Treatment of the animals with N. sativa improved both genotoxicity and ultrastructural changes induced by the two dose levels of CCl[4]

Induction of leukaemia in chloramphenicol-treated toads

Chloramphenicol has been associated with the development of aplastic anaemia. As it is still widely used in Egypt, we studied its effect on 100 Egyptian toads [Bufo regularis] given a dose of chloramphenicol of 5 mg/40 g body weight for 12 weeks. We found it induced numerous, severe ultrastructural changes in almost all types of leukocytes. These changes were similar to those induced by the chemical carcinogen 7,12-dimethylbenz[a]anthracene in 100 toads used as the carcinogen control group, and similar to those in leukocytes reported in humans with leukaemia. We recommend regulations be applied on the use of this antibiotic in countries where it is still widely used