Molecular evaluation of the chemotherapeutic effect of thymoquinone loaded on gold nanoparticles through expression of DNA repair enzymes in induced oral squamous cell carcinoma

Different types of DNA damages occur during the induced oral carcinogenesis, which can be eliminated through several DNA repair pathways. XRCC1 and ERCC1 are the main repair enzymes involved in repair of oral squamous cell carcinoma. A combination of thymoquinone with gold nanoparticles as a novel chemotherapeutic modality is the aim of the present work against chemically induced SCC in the classic model of HBP/DMBA carcinogenesis. One hundred male Syrian golden hamsters were divided into: Group A: Ten animals (negative control), group B: Ten animals (positive control) painted with DMBA only 3times / week/ 12weeks. The rest of animals were painted with DMBA (3times / week/ 12weeks) then painted and injected intraperitoneal with TQ only, 0.01mg/kg TQ-GNps, 0.001mg/kg TQ-GNps or GNps only for 6- and 12- weeks, intervals. By end of the experiment, both pouches from all groups were surgically excised, fresh samples from each pouch were processed for RT-PCR technique. The rest of the pouches were fixed and processed for H&E evaluation. Loading of thymoquinone on gold nanoparticles was promising chemotherapeutic combination, through regression of well-differentiated SCC (positive control) to dysplasia and enhanced expression of the studied DNA repair enzymes compared to either thymoquinone or gold nanoparticles groups.