Description of dog buccal epithelial cells to approximate their use as a biomarker of induced damage in the Buccal Micronucleus Cytome assay

Abstract

The Buccal Micronucleus Cytome assay (BMCyt) is effectively employed to quantify genetic damage in humansexposed to various xenobiotics. Dogs are proposed as valuable animal models for assessing the effects of thesexenobiotics, potentially predicting adverse outcomes in humans. This study first provides a foundational understandingby describing the oral epithelium histology in two healthy canines, characterizing the tissue sourcefor cytological analysis. Subsequently, the BMCyt was conducted on samples from the same buccal area of 36purebred dogs comprising equal numbers of puppies and adults. The potential impact of piperazine, a commondeworming xenobiotic, was also assessed by comparing samples taken before and 19 days after the firstdeworming. Histological analysis revealed the epithelium to be stratified parakeratinized, with some areasexhibiting keratinization. BMCyt results indicated that the frequency of micronuclei and cells with condensedchromatin was significantly higher (six-fold and two-fold, respectively; p < 0.05) in adult dogs compared topuppies, aligning with the expected age-related accumulation of genomic lesions. In piperazine-administeredpuppies, karyolytic cells were twice as frequent post-treatment (p < 0.05), suggesting the BMCyt assay candetect exogenous effects. Additionally, a BMCyt protocol using Feulgen staining followed by sequential Giemsastaining was evaluated in six adult German Shepherds; Giemsa noted for its simplicity and cost-effectiveness. Thiscomprehensive approach, combining detailed histological characterization with the BMCyt assay, establishes arobust basis for assessing genomic integrity in canines. These findings support the potential application of thecanine BMCyt assay as a biomarker in both environmental and clinical studies.