2022, Vol. 26 ›› Issue (20): 3158-3163

Laminaria japonica polysaccharide protects radiation-induced brain injury by regulating the blood-brain barrier in mice

Ao Pian1, Zhao Xin1, Yu Hongrong2, Zhang Siqin1, Zhang Xinyue2, Gu Weili2, Wei Li1, 2   

Abstract: BACKGROUND: Radiotherapy is one of the main methods for the treatment of brain tumors, which significantly improves the clinical efficacy. However, its side effects on normal brain tissue seriously affect the quality of life of patients. Therefore, it is particularly important to find a way to effectively prevent the damage of normal brain tissue and to study its mechanism.
OBJECTIVE: To explore the effect and mechanism of Laminaria japonica polysaccharide intervention on radiation-induced brain injury in mice.
METHODS: Ninety-six male Kunming mice, SPF grade, were randomly divided into four groups (n=24 per group): a control group, an irradiation group, a Laminaria japonica polysaccharide (LJP) group, and an irradiation+LJP group. All mice were given 7-day continuous administration before radiation, and then 60Go γ-rays (30 Gy) were used to establish a radiation brain injury model in mice. Immunofluorescence method was used to detect the expression of fibrinogen and activation and deposition of astrocytes in the brain tissue. The ultrastructural changes of the cerebrovascular system were investigated under transmission electron microscope. The motion trails of the mice in the Morris water maze were observed before and after treatment.
RESULTS AND CONCLUSION: After radiotherapy, the expression of fibrinogen in brain tissue was significantly increased, and astrocytes were obviously activated, while the radiation plus LJP intervention significantly relieved the deposition of fibrinogen in mice. Under the electron microscope, the brain vascular endothelial cells swelled, the basement membrane was broken and shed, and the blood-brain barrier structure changed after radiation. However, the ultrastructural morphology of the mouse blood-brain barrier in the radiation+LJP group was similar to that of the control group. After radiation, the number of times and activity time of the mice passing through the platform area was significantly reduced in the Morris water maze test (P < 0.05), while the activities of the radiation mice in the platform area showed an increasing trend after the LJP intervention. These results suggest that the protective effect of LJP on radiation-induced brain injury may be mainly achieved by maintaining the stability of the blood-brain barrier structure and regulating its permeability.
Key words: Laminaria japonica polysaccharide, fibrinogen, radiation-induced brain injury, astrocyte, blood-brain barrier, cognitive function, tight junction