Aim The aim of this study was to examine the protective effects of vitamin C (VC) and vitamin E (VE) against hysterosalpingography (HSG)-induced epithelial degeneration and proliferation in rat endometrium. total dose of 15C20 mrad. Three hours after exposure, abdominal cavities of all the rats were reopened and uterine horns were removed. The right uterine horns were embedded into paraffin blocks after fixing in 10% formaldehyde for histopathological 62996-74-1 and immunohistochemical examination. Uterine horns on the other side were rapidly excised and stored at ?80C for the examination of expression of microRNAs (miRNAs) and oxidant, antioxidant, apoptotic and antiapoptotic gene expression using real-time polymerase chain reaction (RT-PCR) method. Results No differences were observed in terms of expression of miRNAs and oxidant, antioxidant, apoptotic and anti-apoptotic gene expression between the study groups. Congestion, epithelial degeneration and malondialdehyde immunoreactivity were significantly lower in G3 and G4 groups than in G2 group; no differences were observed between G1, G3 and G4 groups. Ki-67 immunoreactivity score was significantly higher in G2 group when compared with G1, G3 and G4 groups. Caspase-3 immunoreactivity was not statistically different between the groups. Conclusion VC and VE may confer cellular protection against radiation injury induced by HSG in endometrial epithelium. strong class=”kwd-title” Keywords: vitamin C, vitamin E, radiation, endometrium, rat, miRNA Introduction Hysterosalpingography (HSG) is usually a screening and diagnostic tool used in the radiographic examination of ovarian tubes and uterine cavity with injection of a contrast medium. However, HSG is also associated with certain disadvantages since it can be painful and bothersome for the patient 62996-74-1 and also involves exposure to ionizing radiation, although in low doses.1,2 62996-74-1 Ionizing radiation can be defined as an electromagnetic wave or particle that can trigger certain chemical alterations through freeing ions on surfaces with which it interacts. Radiation damage is caused by either a direct interaction with target molecules or indirectly through the effect of chemically or pharmacologically active elements derived mainly from water molecules. After being assimilated, radiation affects the electrons of atoms and molecules in tissue. This process prospects to the formation of positive ions. However, from a biological viewpoint, the most significant alteration at the cellular level is the generation of molecules that carry an unpaired electron in one of the orbitals known as free radicals. Free radicals are compounds IB2 that exist only for several seconds. Radioprotective mechanisms involve the inactivation of free radicals, hydrogen atom binding to target molecules, formation of mixed sulfide compounds and delay in cellular division and induction of hypoxia in tissues. 3 Even though toxicity of exogenous materials has been extensively examined in numerous previous studies,4,5 studies on these chemicals are relatively scarce in number. Therefore, we designed the present study on the basis of the assumption that antioxidant defense mechanisms, apoptotic and anti-apoptotic genes and certain microRNAs (miRNAs) could be activated in response to immune system activity and that the free radicals are released into the organism through the effect of radiation. Thus, from this viewpoint, determination of the expression of antioxidant genes bears significance, which include glutathione reductase (GSR); glutathione peroxidase 3 (GPX3); superoxide dismutase 1 (SOD1); nitric oxide synthase 2 (RAI-NOS); the apoptoticCanti-apoptotic genes warmth shock 70 kDa protein4 (HSP7), Bcl2-associated X protein (BAX), B-cell lymphoma gene-2 (Bcl-2), caspase-3 (CASP3) and malate dehydrogenase 1 (MDH1) and miR-15b, miR-21, miR-34 and miR-98 in the endometrial tissues. Antioxidant response in mammalian cells occurs through the enzymatic and nonenzymatic pathways.4 Although various enzymes play key functions in the enzymatic pathways, the primary function of these enzymes is the maintenance of the redox sense of balance.5 Antioxidant nutrients such as vitamin C (VC) and vitamin E (VE) have also been reported to exhibit protective effects against ionizing radiation damage. In experimental animal studies,.