Evaluation of the Radioprotective Effect of Silver Nanoparticles on Irradiated Submandibular Gland of Adult Albino Rats. A Histological and Sialochemical Study

Head and neck cancers commonly require radiation as part of treatment. Irradiated patients suffer from severe salivary gland impairment. In this study, we investigated the role of silver nanoparticles (AgNPs) in preventing radiation-induced changes in Albino rats’ submandibular glands (SMG). Thirty adult male Albino rats were divided into three groups ten rats each; group I (control) and group II (irradiated group (IR)) received a single dose of 15 Gray (Gy), and group III (AgNPs + IR) received 150 µg/kg of AgNPs and a single dose of 15 Gy. Sialochemical analysis of salivary function has been evaluated. Salivary levels of 8 hydroxydeoxyguanosine (8-OHdG), nitric oxide (NO), and total antioxidant capacity (TAC) have been measured. Histological and ultrastructural examinations of the salivary gland have been assessed. Immunohistochemical expression of malondialdehyde (MDA), superoxide dismutase (SOD), and inducible nitric oxide synthetase (iNOS) were detected. The results showed a significant decrease in salivary gland function and total protein levels in the IR group, contrary to group III. The 8-OHdG and NO levels and the immunohistochemical expression of MDA and iNOS were significantly increased in the IR group. However, the levels of TAC and SOD were significantly decreased. IR group showed atrophy of acinar cells with signs of degeneration, wide intercellular spaces, and cytoplasmic vacuolizations in addition to apoptotic cells. The results of group III showed protection of the submandibular salivary gland from radiation. We concluded that silver nanoparticles could have a protective role against radiotherapy through their antioxidant activity and scavenging of reactive oxygen species (ROS).