Emu Oil and Saireito in combination reduce tumour development and clinical indicators of disease in a mouse model of colitis-associated colorectal cancer

Abstract

BACKGROUND: Emu Oil (EO) previously demonstrated therapeutic potential in a mouse model of colitis-associated CRC (CA-CRC). Saireito, a traditional Japanese medicine, has not been investigated in CA-CRC. AIM: To determine whether EO and Saireito could be therapeutic in an azoxymethane (AOM)/dextran sulphate sodium (DSS) model of CA-CRC. METHODS: Female C57BL/6 mice were assigned to groups (n = 10/group); 1) saline control, 2) saline+Saireito, 3) saline+EO, 4) saline+EO/Saireito, 5) AOM/DSS control, 6) AOM/DSS+Saireito, 7) AOM/DSS+EO and 8) AOM/DSS+EO/Saireito. Mice were intraperitoneally injected with saline or AOM (7.4 mg/kg) on day 0 and underwent three DSS/water cycles (2%w/v DSS for 7 days, 14 days water). Mice were orally-gavaged with either water (80 µL), Saireito (80 µL), EO (80 µL) or EO/Saireito (160 µL; 80 µL EO + 80 µL Saireito) thrice weekly. Daily bodyweight and disease activity index (DAI) were recorded and colonoscopies performed on days 20, 41 and 62. Mice were euthanized on day 63. p < 0.05 was considered statistically significant. RESULTS: AOM/DSS induced significant bodyweight loss throughout the trial (max -36%), which was attenuated by Saireito (max +7%), EO (max +5%) and EO/Saireito (max +14%; p < 0.05). AOM/DSS increased DAI compared to saline controls (p < 0.05), which was reduced by Saireito, EO and EO/Saireito (p < 0.05). All treatments reduced colonoscopically-assessed colitis severity (days 20 and 41; p < 0.05). EO/Saireito further decreased colitis severity compared to Saireito and EO alone (day 20; p < 0.05). Finally, EO and EO/Saireito resulted in fewer colonic tumours compared to AOM/DSS controls (p < 0.05). CONCLUSION: Combined EO and Saireito reduced disease and tumour development in AOM/DSS mice, suggesting therapeutic potential in CA-CRC.