ESTRO 2024 - Abstract Book

S5239

Radiobiology - Normal tissue radiobiology

ESTRO 2024

545

Digital Poster

Structural & functional change of blood-spinal cord barrier after spinal cord irradiation in mice

Haiyan Zeng 1,2,3 , Ligang Xing 4 , Jinming Yu 2 , Yang Li 2 , Xingguo Song 2 , Li Xie 2 , Xingwu Wang 2 , Jie Liu 2 , Bingwen Zou 1 , Shuyu Zhang 1 , Wei Gao 5 , Min Mu 6 , Yi Zhang 1 , Binbin Hu 1 , Lizza Hendriks 7 , Dirk De Ruysscher 3 1 Cancer Center, West China Hospital, Sichuan University,, Department of Radiation Oncology, Division of Thoracic Oncology, Chengdu, China. 2 Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Department of Radiation Oncology and Shandong Provincial Key Laboratory of Radiation Oncology, Jinan, China. 3 GROW School for Oncology and Reproduction, Maastricht University Medical Centre+, Department of Radiation Oncology (Maastro), Maastricht, Netherlands. 4 handong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Department of Radiation Oncology and Shandong Provincial Key Laboratory of Radiation Oncology, Jinan, China. 5 Affiliated Hospital & Clinical Medical College of Chengdu University, Clinical Genetics Laboratory, Chengdu, China. 6 West China Hospital, Sichuan University, Department of Head and Neck Oncology, Cancer Center and State Key Laboratory of Biotherapy,, Chengdu, China. 7 GROW School for Oncology and Reproduction, Maastricht University Medical Centre+, Department of Pulmonary Diseases, Maastricht, Netherlands

Purpose/Objective:

The blood-spinal cord barrier (BSCB) and blood-brain-barrier limit the penetration of systemic therapies to these compartments. We investigated the safety of different irradiation schedules to cervical spines in BALB/C mice and compared the blood-spinal cord barrier (BSCB) injury of once-daily radiotherapy (ODRT) versus twice-daily radiotherapy (TDRT) to evaluate treatment strategies to safely make the BSCB more permeable.

Material/Methods:

Female BALB/C mice of 7-8 weeks old were randomized to two groups for cervical irradiation: ODRT and TDRT. Each groups has two subgroups, normal radiotherapy group (normal- ) and hypofractionated radiotherapy group (hypo-), along with a control group without irradiation. The irradiation dose for the normal-ODRT arm was 60 Gy in 30 fractions (60Gy/30F), once-daily (qd), 5 days per week, 6 weeks in total; and the hypo-ODRT arm was 60 Gy in 3 fractions (60Gy/3F), qd. The irradiation dose for the normal-TDRT arm was 45Gy in 30 fractions (45Gy/30F), twice-daily (bid, interval between fractions > 6 hours), 5 days per week, 3 weeks in total; and the hypo-TDRT arm was 45 Gy in 3 fractions (45Gy/3F), bid. The mice were irradiated using X-ray 225 (Precision X-ray Inc). The irradiation dose rate was 1.985Gy/min. The irradiated mice were deeply anesthetized and perfused, the cervical spines were rapidly removed and fixed to observe the structure of BSCB using transmission electron microscopy (TEM) on 1d, 3d, 7d, 14d, 21d, 28d, 42d, 56d, 77d after irradiation, 3 mice in each group at each time point. The cranial amount of evens blue (EB) was also compared between arms on 1d, 7d, and 14d after irradiation, 6 mice in each group at each time point, to investigate the functional change after irradiation.

Results: