Anxiety-like behavior and morphological changes in amygdala of rats exposed to chemically induced carcinogenesis

Abstract

Oral cancer is the most common malignancy in the head and neck region. Studies have shown that oral cancer patients have high stress and anxiety levels of, which may influence the disease's treatment and prognosis. However, the brain mechanisms involved in anxiety-induced tumor onset and progression are poorly understood. In this study we will evaluate the effects of oral carcinogenesis induced by 4-nitroquinoline-1-oxide (4NQO) on the anxiety behavior and amygdala morphology in rats. The study will be composed by two groups: Group 1 (experimental): 8 male Wistar rats treated with the carcinogen 4NQO mixed in drinking water; Group 2 (control): 8 male Wistar rats treated with drinking water. When the rats from experimental group reach 90 days they will be treated with 4NQO for 120 days, while control rats are maintained with only drinking water. Before the beginning and after 120 days of oral cancer induction, the animal from the both experimental groups will be submitted to specific behavioral tests to assess anxiety levels. Histological analysis will be performed to assess of oral squamous cell carcinoma (OSCC) occurrence in the experimental group. Stereological analysis will be used to evaluate the number and volume of neurons in the amygdala from both groups. Statistical tests will be used to evaluate the carcinogen influence on the anxiety-like behavior and amygdala morphology. This study will allow us to understand new neurobehavioral parameters involved in the induction of chemically induced carcinogenesis. (AU)