Abstract

To explore the radiobiological effects and related mechanisms of brain tissue after craniocerebral irradiation in young rats. Twenty-seven young male rats were randomly divided into high dose group (group C) (n=9), low dose group (group B) (n=9) and control group (group A) (n=9). The brains of rats in the group C were irradiated with 20Gy, while those in the group B were irradiated with 3Gy. The changes of body weight and organ index of rats in the three groups after craniocerebral irradiation were recorded. 1 w later, the rats were killed, the brain tissue was taken out, and the brain tissue sections were stained with hematoxylin and eosin. The migration ability was detected by cell scratch test, the levels of oxidative stress, inflammatory factors and apoptosis factors in brain tissue were observed, and the radiobiological effects and possible mechanism of brain injury were analyzed. At 3 d and 7 d after craniocerebral irradiation, the body weight of rats in the group B and group C was lower than that in the group A, and that in the group C was lower than that in the group B. Compared with the group A, the thymus and spleen organ index of the group B and the group C decreased and the decrease degree of the group C was greater than that of the group B. The normal nerve cells in the hippocampus of rats have large and round nucleoli, clear nucleoli and intact cell membrane. The pathological sections of the group B showed nerve cell injury, swelling, deformation, pale cytoplasm and tissue edema. The results of scratch test showed that the cell migration distance between the group B and the group C was larger than that in the group A at 24 h and 48 h, and the migration distance in the group C was larger than that in the group B. Compared with the group A, the serum superoxide dismutase activity decreased and the malondialdehyde content increased in the group B, while the superoxide dismutase activity and malondialdehyde content in the group C increased compared with the group B. Compared with the group A, the concentrations of tumour necrosis factor-alpha and interleukin-6 in the serum of the group B were increased, and these in the group C were higher than those of the group B. Compared with the group A, the apoptotic factors Bcl-2-associated X-protein and caspase-3 in the group B increased, while the content of B-cell lymphoma 2 decreased. Compared with the group B, the apoptotic factors Bcl-2-associated X-protein and caspase-3 increased and the content of B-cell lymphoma 2 decreased in the group C. Brain irradiation caused radiation-induced pathological damage to the brain tissue of young rats, resulting in weight loss and damage to immune organs in a dose-dependent manner. Its mechanism can be mediated by promoting inflammation, oxidative stress and apoptosis.