Enhanced Radiosensitivity with Hypericum Perforatum in Radiation-induced Radiodermatitis Rat Model

OBJECTIVE Radiation dermatitis is one of the most common radiotherapy-related side effects. There is no gold standard treatment for this side effect, which drastically affects patients’ quality of life. Nevertheless, patients often use over-the-counter products. Hypericum perforatum (St. John’s wort) is one of the most commonly used homemade remedies. In this work, we investigated whether Hypericum perforatum oil augments radiation sensitivity in a rat radiodermatitis model. METHODS Radiation dermatitis was induced in 16 male Sprague-Dawley rats by administration of single fraction 30 Gy external radiotherapy. Rats were randomly assigned to control and Hypericum perforatum oil-treated arms. Starting on the third day before and up to 14 days after radiotherapy, the Hypericum perforatum oil arm was treated with 100 µl of Hypericum perforatum oil 3 times a day. Rats were observed for two weeks to assess acute skin changes, and irradiated rat skin samples were examined histomorphologically by scoring the presence of scarring, the severity of inflammation, and the extent of inflammation. RESULTS More skin reactions were observed in the Hypericum perforatum-treated arm. In the histomorphological examination, the Hypericum perforatum oil-treated arm had higher scores than the control arm in terms of the presence of scarring, the severity of inflammation, and the extent of inflammation. CONCLUSION Our results showed that Hypericum perforatum oil exacerbated radiation dermatitis, and caution should be exercised while recommending it.