7.0 T magnetic resonance imaging evaluation of left ventricular function improvement in rats with pulmonary arterial hypertension in the Qinghai-Tibet Plateau environment following sodium selenite administration:A preliminary study
Objective:To assess the improvement of sodium selenite(SE)on left ventricular function after pulmonary arterial hypertension(PAH)in a high-altitude hypoxic environment using cardiac magnetic resonance tissue tracking(CMR-TT).At the same time,the potential mechanism of SE improving left ventricular function after PAH was preliminarily explored.Materials and Methods:Forty-six male SD rats were relocated overland from Chengdu(altitude 500 m)to the Plateau Animal Laboratory in Yushu Tibetan Autonomous Prefecture,Qinghai Province(altitude 4250 m)the day following their acquisition.Subsequently,they were randomly assigned to one of three groups:a control group(n=10),a model group treated with monocrotaline(MCT)(MCT group,n=20),and a treatment group(SE group,n=16).After being raised in a hypoxic environment for 28 weeks,both the MCT and SE groups of rats were administered a one-time intraperitoneal injection of 60 mg/kg MCT to establish the PAH model,whereas the control group received an equivalent volume of saline injection.One week later,rats in the SE group were treated with 0.7 mg/kg of SE via oral gavage for a continuous period of one month,while the control group and MCT group were kept on routine feeding.Upon completion of the intervention,the rats were transported back to Chengdu where 8 rats from each of the three groups were randomly selected for CMR imaging to assess left ventricular function,strain,and T2 relaxation time.After completing the CMR scan,heart tissue and blood samples are collected from the rat for respective pathological and biochemical analysis.Results:Compared with control group,MCT group of left ventricular ejection fraction(LVEF)(61.36%±4.50%)and left ventricular global circumferential strain(LVGCS)(-19.81%±0.84%)were significantly decreased(all P<0.05).However,LVEF(75.29%±5.67%),left ventricular global radial strain(LVGRS)(42.90%±5.94%),and LVGCS(-21.43%±1.33%)were significantly higher in the SE group compared with the MCT group(all P<0.05).The results showed that SE treatment improved left ventricular function after PAH.The levels of serum glutathione peroxidase(GSH-Px)in the control and MCT groups were statistically significant[control group vs.MCT group:(16 544.38±3 734.02)U/mL vs.(9 974.00±900.80)U/mL,P<0.05],serum malondialdehyde(MDA)increased in MCT group compared to control group[MCT group vs.control group:9.00(7.60,13.20)μmol/L vs.3.86(3.60,6.20)μmol/L,P<0.01],suggesting that the antioxidant capacity of rats in MCT group decreased.After SE intervention,rats in the SE group exhibited increased serum levels of superoxide dismutase(SOD)(292.60±44.38)U/mL and GSH-Px(17 843.26±3 585.44)U/mL as well as decreased MDA levels[5.37(5.10,6.20)μmol/L](all P<0.05).The apoptosis staining showed that the relative fluorescence intensity of the left ventricle of MCT was significantly higher compared with that of control group(P<0.001),whereas SE treatment resulted in a significant decrease in the relative fluorescence intensity of apoptosis staining in the SE group compared with that of the MCT group(P<0.001).Conclusions:The CMR-TT technique enables the quantitative evaluation of left ventricular functional abnormalities following pulmonary arterial hypertension.SE can improve left ventricular function after PAH in hypoxic environment,which may be related to increasing antioxidant capacity and alleviating left ventricular cardiomyocyte apoptosis.
国家科技期刊平台
NSTL
万方数据
维普
