Melatonin reduces radiotherapy-induced hepatocyte apoptosis delivered at different dose rates

Baki K. B., ERDEM E., SAPMAZ T., TOPKARAOĞLU S., ŞEVGİN K., ARAS S.

Radiation Physics and Chemistry, cilt.249, 2026 (SCI-Expanded, Scopus)

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 249
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1016/j.radphyschem.2026.114233
  • Dergi Adı: Radiation Physics and Chemistry
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, EMBASE, INSPEC, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
  • Anahtar Kelimeler: Radiotherapy, Liver damage, Flattening filter, Flattening filter-free, Melatonin, Apoptosis
  • Sağlık Bilimleri Üniversitesi Adresli: Evet

Özet

Background During radiotherapy for abdominal tumors, the liver is frequently exposed to incidental radiation, which can lead to structural and functional damage. Although flattening filter (FF-low dose rate (LDR)) and filter-free (FFF-high dose rate (HDR)) photon beams differ markedly in dose rate and properties, the impact on liver tissue and the protective potential of melatonin (MEL) have not been clearly defined. This study examines the effects of MEL on liver damage induced by these two radiotherapy modalities. Methods Forty adult male rats were divided into five groups: Control, FF-LDR, MEL + FF-LDR, FFF-HDR, and MEL + FFF-HDR. MEL (50 mg/kg) was administered intraperitoneally 15 min before a single abdominopelvic irradiation (8 Gy). Liver tissues were collected 48 h post-irradiation for histopathological and immunohistochemical analyses. Results Both irradiation modalities induced histopathological liver damage and increased apoptotic activity. MEL pretreatment was associated with lower histopathological scores; moreover, it significantly reduced Caspase-3 immunoreactivity. Conclusion The FF and FFF radiotherapy techniques induced similar liver damage despite different dose rates. MEL showed a more pronounced effect on apoptosis, as evidenced by reduced Caspase-3 expression, while its histopathological effects were limited.