Complementary and alternative medicine in reducing radiation-induced skin toxicity

Radiation therapy-induced acute and late effects, particularly skin toxicities, have significant impact on cancer patients' quality of life and long-term survival. To date, no effective topical agents have been routinely used in the clinical setting to prevent skin toxicity. Using SKH-hr1 hairless mice, we investigated two complementary and alternative medicine in their effects on inflammation and ionizing radiation (IR)-induced skin toxicity: Calendula officinalis (CO) and Ching Wan Hung (CWH). They were applied immediately following each IR dosing of 10 Gy/day for 4 days. Skin toxicity and inflammatory factors were evaluated at multiple time points up to 15 days post-radiation. Serum interleukin (IL)-1α, monocyte chemotactic protein-1 (MCP1), keratinocyte-derived chemokine (KC), and granulocyte colony-stimulating factor (G-CSF) were significantly induced by radiation. Both CO and CWH significantly inhibited IR-induced MCP1 (p < 0.01), KC (p < 0.05), and G-CSF (p < 0.001). IR-induced erythema and blood vessel dilation were significantly reduced by CWH (p < 0.001) but not by CO at day 10 post-IR. Both agents inhibited IR-induced IL-1α (p < 0.01), MCP1 (p < 0.05), and vascular endothelial growth factor (p < 0.05). There were continuous inhibitory effects of CWH on IR-induced skin toxicities and inflammation. In contrast, CO treatment resulted in skin reactions compared to IR alone. Our results suggest that both CO and CWH reduce IR-induced inflammation and CWH reduced IR-induced erythema. In summary, CWH showed promising effects in reducing IR-related inflammation and skin toxicities, and future proof-of-principal testing in humans will be critical in evaluating its potential application in preventing IR-induced skin toxicities.