ESTRO 2025 - Abstract Book

S3911

Radiobiology - Normal tissue radiobiology

ESTRO 2025

453

Digital Poster The Role of Tenascin C as an Early Detection Marker for Radiation-Induced Cardiotoxicity and the Impact of Melatonin Dosage-in vivo rat study Ecem Demir 1 , Fazilet Hidayet Öner Dinçbaş 2 , Karolin Yanar 3 , Pınar Atukeren 3 , Serbay Özkan 4 , Gözde Erkanlı Şentürk 5 , Melike Güler Ülker 6 , Şefika Arzu Ergen 2 , Songül Karaçam 2 1 Radiation Oncology, Cam and Sakura Hospital, Istanbul, Turkey. 2 Radiation Oncology, IUC-Cerrahpasa Faculty of Medicine, Istanbul, Turkey. 3 Medical Biochemistry, IUC-Cerrahpasa Faculty of Medicine, Istanbul, Turkey. 4 Histology And Embryology, Izmir Katipcelebi University Faculty of Medicine, Izmir, Turkey. 5 Histology And Embryology, IUC Cerrahpasa Faculty of Medicine, Istanbul, Turkey. 6 Thoracic Surgery, Tekirdag Provincial Health Directorate Dr. Ismail Fehmi Cumalioglu City Hospital, Tekirdag, Turkey Purpose/Objective: To investigate the effectiveness of the Tenascin-C marker in the early detection of cardiac toxicity following thoracic radiotherapy (RT) in rats and to provide novel scientific information regarding the appropriate dosage of melatonin, potential an antioxidant and radioprotective agent. Material/Methods: A total of 45 adult male Sprague-Dawley rats were divided equally into five groups. The control group received 1 ml saline solution and sham irradiation. Group 2 had 1 ml saline followed by 12 Gy RT in 1 fraction. Groups 3, 4 and 5 were irradiated in the same way and instead of saline, melatonin was administered at a dose of 100 mg/kg, 50 mg/kg and 5 mg/kg. Eight weeks later, Tenascin C levels, oxidation markers and histological changes in the heart were examined.

Results:

Tenascin levels were significantly higher in the RT only group. In melatonin-treated groups, 5 mg/kg dose was found to be more effective in preventing protein oxidation and lipid peroxidation. The levels of advanced glycation end products were significantly lower in 5 mg/kg and 50 mg/kg melatonin groups compared to the RT only group. When antioxidant markers were evaluated, it was observed that 5 mg/kg melatonin caused a significant increase, while other doses caused an increase only in superoxide dismutase activity. Evaluation heart tissues showed that the damage was significantly improved in all melatonin-treated groups.