Assessing Genotoxic Risk: The InVivo Bone Marrow Chromosomal Aberration Assay

Genotoxicity, the potential of certain agents to cause damage to the genetic material within cells, is a critical concern in chemical safety evaluations due to its association with carcinogenesis and heritable genetic disorders. Pesticides, widely employed in agriculture, are among the major contributors to environmental genotoxins, necessitating rigorous toxicological assessment. The in vivo bone marrow chromosomal aberration assay is a well-established method endorsed by the OECD for evaluating the genotoxic potential of chemical substances. This assay utilizes rapidly dividing hematopoietic cells in rodent bone marrow to detect structural and numerical chromosomal abnormalities under physiological conditions, accounting for factors such as metabolism and DNA repair. Rodents are exposed to the test compound followed by colchicine treatment to arrest cells in metaphase. Bone marrow is then collected, processed, and stained for microscopic examination. Key endpoints include the mitotic index and frequency of aberrant metaphase cells. Despite its limitation in detecting damage in non-dividing tissues, this assay remains a cornerstone in genotoxicity testing due to its high sensitivity and biological relevance. When used in conjunction with in vitro methods, it contributes to a comprehensive assessment of genotoxic risk, thereby supporting regulatory frameworks and public health protection.