Radiation induces changes in toll-like receptors of the uterine cervix of the rat

Radiotherapy is an important therapeutic approach against cervical cancer but associated with adverse effects including vaginal fibrosis and dyspareunia. We here assessed the immunological and oxidative responses to cervical irradiation in an animal model for radiation-induced cervicitis. Rats were sedated and either exposed to 20 Gy of ionising radiation given by a linear accelerator or only sedated (controls) and euthanized 1-14 days later. The expressions of toll-like receptors (TLRs) and coupled intracellular pathways in the cervix were assessed with immunohistofluorescence and western blot. Expression of cytokines were analysed with the Bio-Plex Suspension Array System (Bio-Rad). We showed that TLRs 2-9 were expressed in the rat cervix and cervical irradiation induced up-regulation of TLR5, TRIF and NF-kappa B. In the irradiated cervical epithelium, TLR5 and TRIF were increased in concert with an up-regulation of oxidative stress (8-OHdG) and antioxidant enzymes (SOD-1 and catalase). G-CSF, M-CSF, IL-10, IL-17A, IL-18 and RANTES expressions in the cervix decreased two weeks after cervical irradiation. In conclusion, the rat uterine cervix expresses the TLRs 2-9. Cervical irradiation induces immunological changes and oxidative stress, which could have importance in the development of adverse effects to radiotherapy.