Pre-irradiation effects of ectoine on radiation-induced cardiotoxicity in female Swiss albino mice model

Ectoine is a compatible solute that acts as a natural protectant. In the mice model, a single post-irradiation ectoine dose showed protective effects by modulating both inflammatory and oxidative stress pathways. The effect of ectoine has never been tested on mice cardiac tissue, thus the current study aimed to explore the pre-irradiation effect(s) of ectoine on radiation-induced cardiotoxicity. Forty female Swiss albino mice (17.6-23.1 g); controls (injected intraperitoneally for ten days with 0.2 mL saline), ectoine groups injected with 20 mg/kg of ectoine for ten days), irradiated groups (injected intraperitoneally for ten days with 0.2 mL saline then received six Gy whole body x-irradiation single dose), ectoine irradiated groups (injected with ectoine for ten days then irradiated). Animals were sacrificed on days seven, and 14 (five animals each). Hearts were examined for histological changes and immune-stained for Bax. Ectoine concentration in hearts was measured by HPLC. Serum cardiac troponin T, Total antioxidant capacity, and apoptosis-inducing factor were evaluated by mice with ready-to-use ELISA kits. Heart histological changes were documented in 40% of the 7- & 14-days post-irradiation. Ectoine concentrations (0.63 x 10 -4 mg/mg of heart weight) were higher in ectoine groups than ectoine irradiated groups (0.011 x 10 -4 mg/mg) 14-days post-treatment. Serum troponin T significantly differed between the 14 days groups ( p = 0.032). Apoptosis inducible factor significantly increased in ectoine irradiated group (at 14 days) than those of control ( p = 0.014), irradiated ( p = 0.020), and ectoine ( p = 0.033) groups. Bax showed strong to moderate immunostaining in ectoine and irradiated groups. In conclusion, Ectoine has pre-irradiation partial protective effects on heart cytotoxicity.