Effect of radiation on brain tissue endothelin-1 level and tumor development

Radiotherapy causes injury in the endothelial cells of blood vessels and the production of vasoactive amines such as endothelin-1 (ET-1). ET-1 is an important peptide in cancer development. In this study, the effects of radiation on brain tissue ET-1 level were evaluated. Is it possible to suggest a mechanism using ET-1 level in the production of this adverse effect? In this paper, the relationship between the development of brain tumors and the ET-1 level has been discussed.

Twenty-eight adult Sprague Dawley rats were used in the experiments. The rats were divided into four groups (n = 7) as follows: control group: radiation was not applied during the experiment; Group 1: Decapitated on the 1^st day following radiation; Group 2: Decapitated on the 7^th day following radiation; and Group 3: Decapitated on the 30^th day following radiation. ET-1 levels were measured with enzyme-linked immunosorbent assay (ELISA) method. The t-test, variance analysis, and Tukey honestly significant difference (HSD) tests were used in the statistical analysis. A value of P < 0.05 was accepted as significant.

No statistical differences were observed in the tissue ET-1 levels between the control group and other groups. According to the variance analysis and Tukey test, the differences between the groups were not significant.

We observed in this study that the effects of radiation on brain tumor development or malignant transformation are not mediated by ET-1 levels. In addition, these results support the hypothesis of the fact that medical treatment with ET-1 antagonists in clinical cases receiving radiotheraphy is unnecessary.