The influence of sleep restriction on expression of apoptosis regulatory proteins p53, Bcl‐2 and Bax following rat tongue carcinogenesis induced by 4‐nitroquinoline 1‐oxide

PURPOSE: The aim of this study was to evaluate whether sleep restriction (SR) could affect the mechanisms and pathways' essentials for cancer cells in tongue cancer induced by 4-nitroquinoline 1-oxide in Wistar rats. METHODS: The animals were distributed into 4 groups of 5 animals each treated with 50 ppm 4 NQO solution through their drinking water for 4 and 12 weeks. The animals were submitted to sleep restriction for 21 days using the modified multiple platform method, which consisted of placing 5 rats in a cage (41 × 34 × 16 cm) containing 10 circular platforms (3.5 cm in diameter) with water 1 cm below the upper surface. The investigations were conducted using immunohistochemistry of p53, Bax and Bcl-2 proteins related to apoptosis and its pathways. RESULTS: Although no histopathologic abnormalities were induced in the epithelium after 4 weeks of carcinogen exposure in all groups, in 12 weeks were observed pre-neoplastic lesions. Data analysis revealed statistically significant differences (P < 0.05) in 4 weeks group for p53, and for bcl-2. Following 12 weeks of 4NQO administration, we found significant differences between SR and control groups in p53, bax, and bcl-2 immunoexpression. CONCLUSION: Our results reveal that sleep restriction exerted alterations in proteins associated with proliferation and apoptosis in carcinogenesis.