This study focuses on the development and characterization of a modified 4NQO-induced tongue tumour model of oral squamous cell carcinoma (OSCC) in C57BL/6 mice. Unlike the conventional continuous 4NQO exposure for 16 weeks followed by a no-treatment phase, this protocol employs a thrice-weekly dosing schedule for 28 weeks. The strategic modification was designed to reduce 4NQO-associated toxicity and mortality while creating a therapeutic window for administering chemopreventive agents in an ad libitum setting.

Head and neck squamous cell carcinomas (HNSCCs) is a complex and heterogeneous disease regulated at multiple levels and associated with high mortality and morbidity. HNSCCs are related to environmental risk factors, especially excessive tobacco and alcohol consumption. Oral squamous cell carcinomas (OSCCs) are the prevalent forms of HNSCC, representing approximately 90% of all tumors in this region. The high mortality associated with OSCC is related mainly to the locoregional advancement of the disease.

Hydrogen has three naturally occurring isotopes, the stable forms; the Protium (1H), and Deuterium (2H), while the unstable radioactive form is Tritium (3H). Of the stable isotopes of hydrogen, Deuterium (D) and protium (H) have different chemical and physical properties. The ratio of Deuterium to hydrogen (D/H) in natural water is approximately 1:6600, and the natural fraction of Deuterium is approximately 0.0139–0.0151%. When the deuterium concentration is lower than 0.015% (150 ppm), the fraction is called ‘light water’ or deuterium-depleted water (DDW).