Spontaneous alveolar bone loss after 4NQO exposure in Wistar rats.

OBJECTIVE: This study evaluated the effect of an experimental carcinogenic, 4-Nitroquinoline 1-oxide (4NQO), in the spontaneous alveolar bone loss (ABL) in an animal model. DESIGN: Twenty-two male Wistar rats were included in this study. They were randomly divided into two groups: the control group (n = 10) received food and water ad libitum, and the test group (n = 12) receive the same food; however, 25 ppm of 4NQO was diluted in the drinking water. All animals were euthanized after 20 weeks, and the tongues were removed and analyzed macroscopically to determine the presence of oral mucosal lesions. All specimens were paraffin-embedded and histological sections were obtained. The microscopic analysis was based on routine procedure (haematoxylin and eosin stain). The analysis of spontaneous ABL was performed by a calibrated examiner using standardized photographs and imaging software. Differences in spontaneous ABL were assessed among the three resulting groups: control, 4NQO with oral squamous cell carcinoma (OSCC), and 4NQO without OSCC. RESULTS: In the 4NQO-treated group, nine animals developed OSCC. The animals in the 4NQO with OSCC group presented significantly more spontaneous ABL (0.65 ±â€¯0.21 mm) than the control group (0.34 ±â€¯0.05) (p < 0.001). The animals in the 4NQO without OSCC group showed a mean spontaneous ABL of 0.47 ±â€¯0.13 mm, which was not statistically significant different when compared to the control group (p = 0.096). CONCLUSIONS: It was concluded that the presence of OSCC enhanced spontaneous ABL in Wistar rats when compared to control animals. Additionally, it was shown that, solely, administration of 4NQO may not be considered responsible for alveolar bone destruction.