Radioprotective effect of melatonin against flattening filter-free irradiation-induced rat parotid gland damage

Abstract

The purpose of the present study is to investigate the protective effect of melatonin against early period parotid gland damage, caused by low- and high-dose rate beams in different dose plans, by using experimental rat models. Eighty Sprague Dawley rats were divided into ten randomized groups, each group being different in terms of dose plan and dose rate. Subjects in the control group were given only sodium chloride. Subjects in the melatonin-only group received 10 mg/kg melatonin. The head and neck region of each rat in radiotherapy only and radiotherapy plus melatonin group was irradiated with single dose (SD) and fractional dose (FD) Flattening Filter (FF) and Flattening Filter-Free (FFF) beams. Radiotherapy plus melatonin group subjects were administered 10 mg/kg melatonin 15 min before radiotherapy, radiotherapy only group did not receive melatonin treatment. Ten days after radiotherapy, the parotid gland of rats was examined for histopathological changes and blood samples were collected for biochemical analysis. When radiotherapy only groups and the control group are compared, for both FF, FFF beam modes and single, fractional dose plans, we observed statistically significant difference in histopathology and biochemical parameters due to irradiation. Melatonin administration in radiotherapy plus melatonin groups contributed to conserving these parameters (p < 0.05). In conclusion, melatonin acts as a significant protective agent against early rat parotid gland damage in varying dose plans for both FF and FFF beams. A difference in radiation-induced damage was not observed between FF and FFF beams using in vivo rat model.

KEYWORDS:

• Radiotherapy
• flattening filter free
• parotid gland
• histopathology
• biochemistry
• melatonin

Acknowledgements

Authors are thankful to Medical Physicist Süleyman Çelebi and Radiotherapy Technician Ümmü Alatlı from the Department of Radiation Oncology, Haydarpasa Numune Training and Research Hospital for their support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by the Scientific Research Projects (BAP) Grants Unit, University of Health Sciences, Istanbul, Turkey [grant number: 2019/055].

Notes on contributors

Serhat Aras

Serhat Aras, PhD is an Assistant Professor of Medical Imaging Techniques and a Senior Researcher in University of Health Sciences in Istanbul, Turkey.

Ihsan Oguz Tanzer

Ihsan Oguz Tanzer, PhD is an Assistant Professor of Biomedical Engineering and a Senior Researcher in University of Health Sciences in Istanbul, Turkey.

Seyhan Karacavus

Seyhan Karacavus, MD is an Associate professor of Department of Nuclear Medicine, Kayseri City Training and Research Hospital and a Senior Researcher in University of Health Sciences, in Istanbul Turkey.

Neslihan Sayir

Neslihan Sayir, MD is an Assistant professor of Pathology Laboratory Techniques and a Senior Researcher in University of Health Sciences in Istanbul, Turkey.

Esra Erdem

Esra Erdem, MSc is an Instructor of Pathology Laboratory Techniques and a Senior Researcher in University of Health Sciences in Istanbul, Turkey.

Fatih Hacimustafaoglu

Fatih Hacimustafaoglu, MSc is an Instructor of Medical Laboratory Techniques and a Senior Researcher in University of Health Sciences in Istanbul, Turkey.

Ceren Ezgi Erdogan

Ceren Ezgi Erdogan, MSc is an Medical Physicist of Department of Radiation Oncology and a Haydarpasa Numune Training and Research Hospital, University of Health Sciences Turkey, Turkey.

Tansel Sapmaz

Tansel Sapmaz, MD is an Assistant professor of Department of Histology and Embryology and a Senior Researcher in University of Health Sciences in Istanbul, Turkey.

Turkan Ikizceli

Turkan Ikizceli, MD is an Assistant professor of Department of Radiology, Haseki Training and Research Hospital and a Senior Researcher in University of Health Sciences in Istanbul, Turkey.

Halime Hanim Pence

Halime Hanim Pence, MD is an Associate professor of Department of Biochemistry and a Senior Researcher in University of Health Sciences in Istanbul, Turkey.

Kursad Nuri Baydili

Kursad Nuri Baydili, MSc is an Instructor of Management and Organization and a Senior Researcher in University of Health Sciences in Istanbul, Turkey.

Tolga Katmer

Tolga Katmer, MD is an doctor of Department of General Surgery, Haydarpasa Numune Training and Research Hospital, University of Health Sciences Turkey, Turkey.