The Cytogenetic Effects of NPYR on Mice


Abstract: The effects of N-nitrosopyrrolidine (NPYR) on mice chromosomes and micronucleus induction were investigated in order to evaluate its genotoxic effects. Twenty 10-12 week old mice and 40 8- 10 week old male mice ( Mus musculus var. albinos) were used for chromosome analysis without sex discrimination and micronucleus tests respectively. Mice were intraperitoneally treated in single injections with three dose levels (100, 200 and 300 mg/kg) of NPYR with isotonic saline as the solvent vehicle. Bone marrow was sampled at 24 and 48 h postinjection. Examination of the mice bone marrow chromosomes at the metaphase (24 h) showed that in terms of break and gap, there was an important difference (P<0.05) between groups of the drug doses 100, 200, 300 mg/kg when compared with the controls. In terms of joined telomers, the 100 and 200 mg/kg dosages were not significant (P>0.005), whereas, 300 mg/kg dosage was significant (P<0.05) when compared with the controls. NPYR resulted in a significant dose-related increase in the number of micronucleated polychromatic erythrocytes (MPCE) at the 24 and 48 h sampling time for all doses tested. All dosages also induced statistically significant increases (P<0.05) in the number of MPCEs. Overall, our study showed that NPYR had genotoxic activity. On the other hand, the correlation between increased number of chromosomal breaks and MPCEs supported the presence of an important relationship between the two tests.

Keywords: N-nitrosopyrrolidine, Chromosomal aberrations, Micronuclei

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