Nucleolar organizer regions in a chronic stress and oral cancer model

This study aimed to examine the role of chronic restraint stress (RS) on oral squamous cell carcinomas induced by 4-nitroquinoline-1-oxide (4-NQO) in CF-1 mouse tongues, measured by the expression of argyrophilic staining of nucleolar organizer regions (AgNOR). Thirty one samples of lingual epithelial tissue of CF-1 mice with a diagnosis of oral squamous cell carcinoma (OSSC) were assigned to two experimental groups: the RS/4-NQO group, where animals received RS and induction of oral chemical carcinogenesis (n=17); and the 4-NQO group, where animals received induction of chemical carcinogenesis without restraint stress (n=14). The mean number and distribution pattern of AgNOR were recorded. The mean AgNOR number per cell was found to be slightly higher in the 4-NQO group. AgNOR in the RS/4-NQO group revealed a higher tendency to be arranged in a clumped distribution compared to the 4-NQO group. No statistically significant difference was found between the groups. In conclusion, the induction of chronic restraint stress in CF-1 mice does not increase the number or affect the distribution pattern of AgNORs in OSSC induced by 4-NQO.