Protective effects of boron on radiation-induced intestinal injury and associated microRNA changes

Radiation-induced intestinal injury (RIII) remains a significant dose-limiting toxicity despite advances in radiotherapy techniques. Boron has been suggested to exert beneficial effects on intestinal structure and oxidative stress; however, its potential radioprotective effects have not been fully characterized. This study investigated the effects of boron on histological, immunohistochemical, and circulating miRNA changes in an experimental model of RIII.

A single fraction of 8 Gy whole-body irradiation was delivered, and animals were evaluated on days 2 and 6 post-irradiation. Intestinal injury was assessed by histopathological scoring, villus height (VH), crypt-depth (CD), and VH/CD ratio. Immuno-histochemical expression of transforming growth factor beta 1 (TGF-β1) and matrix metalloproteinase-1 (MMP-1) was evaluated using H-score analysis. Circulating miRNA expression profiles were analyzed by quantitative real-time PCR using the 2^-ΔΔCt method.

Irradiation caused marked intestinal damage, particularly in the acute phase, characterized by villus shortening, crypt injury, and increased histopathological scores. Boron administration partially preserved intestinal architecture, with significant protection of VH and CD, especially at day 2. TGF-β1 and MMP-1 expression was reduced following irradiation but was partially preserved in boron-treated irradiated groups, particularly within the crypt compartment. Irradiation induced significant, time-dependent alterations in circulating miR-150-5p, miR-320a-5p, miR-30a-5p, and miR-200b-5p, while boron administration modulated these radiation-associated miRNA changes.

Boron mitigates RIII and is associated with partial preservation of epithelial structure, modulation of TGF-β1 and MMP-1 expression, and regulation of radiation-responsive circulating miRNAs. These findings support further investigation of boron-based approaches in intestinal radioprotection.