Although safe doses of radiation have been determined, concerns about the harmful effects of low-dose radiation persist. In particular, to date, few studies have investigated the correlation between low-dose radiation and disease development. Asthma is a common chronic inflammatory airway disease that is recognized as a major public health problem. In this study, we evaluated the effects of low-dose-rate chronic irradiation on allergic asthma in a murine model. Mice were sensitized and airway-challenged with ovalbumin (OVA) and were exposed to continuous low-dose-rate irradiation (0.554 or 1.818 mGy/h) for 24 days after initial sensitization. The effects of chronic radiation on proinflammatory cytokines and the activity of matrix metalloproteinase-9 (MMP-9) were investigated. Exposure to low-dose-rate chronic irradiation significantly decreased the number of inflammatory cells, methylcholine responsiveness (PenH value), and the levels of OVA-specific immunoglobulin E, interleukin (IL)-4, and IL-5. Furthermore, airway inflammation and the mucus production in lung tissue were attenuated and elevated MMP-9 expression and activity induced by OVA challenge were significantly suppressed. These results indicate that low-dose-rate chronic irradiation suppresses allergic asthma induced by OVA challenge and does not exert any adverse effects on asthma development. Our findings can potentially provide toxicological guidance for the safe use of radiation and relieve the general anxiety about exposure to low-dose radiation.

Curcumin protects the skin against radiation-induced epidermal damage and prevents morphological changes induced by irradiation skin, thereby maintaining the epidermal thickness and cell density of basal layers. In this study, the effects of topical curcumin treatment on radiation burns were evaluated in a mini-pig model. Histological and clinical changes were observed five weeks after radiation exposure to the back (60Co gamma-radiation, 50 Gy). Curcumin was applied topically to irradiated skin (200 mg/cm2) twice a day for 35 days. Curcumin application decreased the epithelial desquamation after irradiation. Additionally, when compared to the vehicle-treated group, the curcumin-treated group showed reduced expression of cyclooxygenase-2 and nuclear factor-kappaB. Furthermore, irradiation prolonged healing of biopsy wounds in the exposed area, whereas curcumin treatment stimulated wound healing. These results suggest that curcumin can improve epithelial cell survival and recovery in the skin and therefore be used to treat radiation burns.

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BackgroundRecent studies report that inflammatory diseases of the large intestine are associated with colorectal cancer. Geijigajakyak Decoction (GJD) has antispasmodic and anti-inflammatory effects on the gastrointestinal tract. Thus, in light of the connection between chronic bowel inflammation and colorectal cancer (CRC), we asked whether GJD inhibits colorectal tumorigenesis.MethodsThe effects of GJD on the viability and proliferation of CRC cells were evaluated using MTT and BrdU assays, respectively. The motility of CRC cells was examined by a Transwell migration/invasion assay and immunoblot analysis was used to examine the signaling pathways associated with migration. A syngeneic Balb/c mice allograft model, in which CT26 cells were injected into the dorsum, was used to evaluate the anti-tumor effects of GJD in vivo.ResultsGJD had no cytotoxic effects against HCT116 CRC cells, although it did inhibit their proliferation. GJD inhibited the migration of HCT116 cells, and suppressed the invasion of HCT116, Caco2, and CSC221 CRC cells. In addition, GJD downregulated the expression of p-JNK and p-p38 MAPK, which are downstream signaling molecules associated with invasiveness. Furthermore, oral administration of GJD (333 mg/kg, twice a day) inhibited tumor growth in a mouse xenograft model.ConclusionsGJD inhibited the motility of human CRC cells and suppressed tumorigenesis in a mouse model. These results suggest that GJD warrants further study as a potential adjuvant anti-cancer therapy.Electronic supplementary materialThe online version of this article (doi:10.1186/s12906-016-1281-z) contains supplementary material, which is available to authorized users.