Effects of local heart irradiation with ?-rays on cardiac function ex vivo in rats / 解放军医学杂志

ABSTRACT

Objective To investigate the pathophysiological changes in irradiation-induced heart injury in rats in order to provide preventive and therapeutic strategies for irradiation-induced heart disease(RIHD).Methods Experiments were performed using female Wistar rats with body weight of approximately 220g.12 female Wistar rats were randomly assigned to two groups(sham-irradiated group and irradiated group).Heart of rats was locally irradiated with 60Co ?-ray at a dosage of 20 Gy.During the post-radiation period,the intake of food and activities of the animals were observed daily and the body weight was recorded monthly.On the 120th day after irradiation,myocardial perfusion was tested using real time myocardial contrast echocardiography(RTMCE).On the 180th day after irradiation,the hearts were isolated from the rats of the both groups,and they were perfused with a Langendorff apparatus.Hemodynamic measurements,including peak systolic LV pressure(LVSP),maximal rate of LV pressure rise(LV dp/dtmax)and fall(LV dp/dtmin)were studied.Then the hearts were examined pathologically with HE staining.Results Animals irradiated with single dose of 20Gy locally were apparently in a good condition during the observation period of 180 days.No differences in food intake,physical activities and body weight were observed between irradiated and control animals.However,myocardial blood velocity(beta)of irradiated rats was significantly lower than that of sham irradiated group(P