Proteomic analysis of acute radiation-induced rectal injury in rats

Objective

To comprehensively elucidate overall protein alterations associated with acute radiation-induced rectal injury in rats.

Methods

A rat model of acute radiation-induced rectal injury was established by irradiating rectal segments with a single dose of 17.5 ​Gy X-rays. These segments were then collected at 7 d and 10 ​d post-irradiation. Tandem mass tag-based quantitative proteomic analysis was then performed.

Results

65,526 peptides were identified, corresponding to 8,088 proteins. Hematoxylin-eosin staining revealed characteristic epithelial cell degeneration and necrosis, intestinal gland atrophy and dilatation, and interstitial inflammatory cell infiltration. Inflammation was more pronounced in the 10 d irradiation group than in the 7 d irradiation group. Overall, 127 up- and 108 downregulated proteins were identified at 7 d post-irradiation, and 122 up- and 44 downregulated proteins were identified at 10 d post-irradiation. Notably, 17 up- and 6 downregulated proteins were consistently co-expressed at both time points. The expression of three of these proteins was validated via real-time quantitative PCR: polypeptide YY (Pyy), thymidylate synthase (Tyms), and tetraspanin (CD9). Tyms transcript levels were significantly higher in irradiated rectal tissues (P ​< ​0.05). Pyy transcript levels were significantly higher at both time points (P ​< ​0.05). Finally, CD9 mRNA expression was significantly lower in both the 7 d and 10 d irradiation groups (P ​< ​0.05).

Conclusions

The potential targets were found to prevent and treat acute radiation-induced rectal injury in clinical practice.