Histopathological investigation of the effects of FF and FFF beams on inflammation, stromal response, apoptosis, proliferation and DNA damage in lung cancer radiotherapy
Radiation Physics and Chemistry, cilt.247, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 247
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.radphyschem.2026.114046
- 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, FFF beam, Lung cancer, Apoptosis, Proliferation, DNA damage
- Sağlık Bilimleri Üniversitesi Adresli: Evet
Özet
This study aims to investigate the histopathological effects of Flattening Filter (FF) and Flattening Filter Free (FFF) beams on apoptosis, DNA damage response (p53), cell proliferation (Ki-67), anti-apoptotic activity (Bcl-2), early stromal response and inflammation in an in-vivo non-small cell lung cancer (NSCLC) model. Adult female outbred athymic nude mice were randomly assigned to five groups: a control group (G1), an NSCLC model without radiotherapy (G2), and three radiotherapy groups receiving a single 20 Gy dose at different dose rates: FF-400 MU/min (G3), FFF-1000 MU/min (G4), and FFF-1800 MU/min (G5). Tumour xenografts were created using A549 NSCLC cells. Animals received a single dose of 20 Gy radiotherapy delivered by a Varian Trilogy linear accelerator under general anaesthesia at varying dose rates of 400 MU/min in FF mode and 1000 MU/min and 1800 MU/min in FFF mode. After euthanasia (48 h post-radiotherapy), tumor tissues were collected and analyzed histopathologically. Apoptosis was assessed via TUNEL assay (IHC), while p53, Ki-67, and Bcl-2 expression (IF) were evaluated using immunofluorescence (IF) and immunohistochemistry (IHC). H&E and Masson's Trichrome staining were performed to assess inflammatory cell infiltration and early stromal response. Histopathological scoring was performed by two blinded histologists. Statistical significance was determined using independent samples t -test (p < 0.05). Radiotherapy significantly increased apoptosis in radiotherapy groups (G3, G4, G5), with the highest apoptotic index observed in the FFF-1800 MU/min group (p < 0.05). p53 expression increased in a dose-dependent manner, with FFF beams inducing stronger DNA damage responses. Ki-67 proliferation index decreased significantly post-radiotherapy, with the greatest reduction in FFF-1800 MU/min (p < 0.05). Bcl-2 expression was markedly lower in radiotherapy groups. Inflammatory cell density decreased significantly in a dose-dependent manner, with FFF-1800 MU/min showing superior suppression (p < 0.05). Early stromal response formation was the most pronounced in G5. FFF beams were associated with enhanced biological responses. These findings indicate that FFF regimens are associated with enhanced acute tumor biological responses in this experimental model; however, their long-term therapeutic implications require further investigation.