Micronucleus Test (MNT)

Micronucleus test was performed to evaluate the IONPs induced clastogenic effect and its amelioration by thymoquinone in rat bone marrow cells. The MN test was done as per the protocol of Schmidt²⁹ and modified by Ahmad et al.³⁰. Briefly, after completion of the duration of treatment, the femur bones of the rats were dissected out. The bone marrow was flushed out with fetal bovine serum (FBS) and was centrifuged at 300 g for 10 min and the supernatant was discarded. The pellets were resuspended in a little amount of FBS. The smears were drawn on the pre-coded clean slides and left to air dry. Differential staining was done in May-Gruenwald stain followed by Giemsa stain (5%). The slides were then mounted in DPX and analyzed under a light microscope (Nikon, Japan). The frequencies of micronucleated polychromatic erythrocytes (MNPCEs) were calculated by scoring 2000 polychromatic erythrocytes (PCEs) per animal.