The micronucleus (MN) assay is widely used to assess the genotoxicity and cytotoxicity of various agents in different species. One of the key factors that can affect the accuracy of micronuclei (MNi) scoring is the staining protocol. Thus, this study aimed to investigate the effect of different staining protocols on the scoring accuracy of micronuclei induced by gamma irradiation in male rats. Male rats were exposed to a single dose of 6Gy were γ-irradiation and euthanized 24 hours later. Bone marrow cells collected and an MN assay was prepared using different staining protocols, including Giemsa (G), Feulgen (F), Hematoxylin & Eosin (HE), and a combination of Feulgen and Hematoxylin & Eosin (F-HE). The results revealed significant differences between the scored MNi frequencies using different stains as compared with each other. In conclusion, there is an interaction between staining techniques and the scoring accuracy of MNi and aberrant cell frequencies. Therefore, standardization and choice of staining protocols are critical for reliable and consistent results in micronucleus assays.
