Speckle tracking imaging in evaluation of early myocardial injury of sepsis rats and effect of naringin pretreatment / 中国医学影像技术

ABSTRACT

Objective: To investigate the value of speckle tracking imaging (STI) technique in evaluating lipopolysaccharide (LPS) induced early myocardial injury in sepsis rats and naringin (Nar) pretreatment in reversing myocardial injury. Methods: Thirty-six SD rats were randomly divided into LPS+Nar50 group (n=9), LPS+Nar100 group (n=9), LPS group (n=10) and control group (n=8). Rats in LPS+Nar50 group and LPS+Nar100 group were given Nar suspension by gavage with 50, 100 mg/kg, respectively, while in other two groups were given the same amount of normal saline. Continuous gavage was performed for 7 days, then rats in LPS +Nar50 group, LPS+Nar100 group and LPS group were intraperitoneally injected with 5 mg/kg LPS 1 hour after the last gavage, while in control group were given the same amount of normal saline. Six hours after LPS injection, all rats were tested for left ventricular ejection fraction (LVEF) and Tei index, peak circumferential strain (SC) at each segment of the left ventricle (LV), LV global subendocardial, middle and subepicardial SC (respectively for GSCendo, GSCmid, GSCepi), systolic peak rate of SC (SrC S), peak early diastolic SC rate (SrC E), late diastolic peak rate of SC (SrC A). Serum levels of creatine kinase (CK) and lactate dehydrogenase (LDH) were detected, and pathological changes of myocardial tissue were observed by HE. Results: The peaks of SC at each segment of LV in LPS group were lower than those in control group and LPS+Nar100 group (all P<0.05). In LPS+Nar50 group, SC peaks of anterior septum, anterior wall, inferior wall and posterior septum were higher than those in LPS group but lower than those in LPS+Nar100 group SC peak of lateral wall in LPS+Nar50 group was lower than that in LPS+Nar100 group (all P<0.05). LVEF, GSCendo, GSCmid, SrC S, SrC E and SrC A in LPS group were significantly lower than the other three groups, and Tei index, CK and LDH were all higher than in the other three groups (all P<0.05). LVEF, GSCmid, SrC S, SrC E and SrC A in LPS+Nar50 group were lower than those in LPS+Nar100 group, while Tei index, CK and LDH were all higher than those in LPS+Nar100 group (all P<0.05). Pathological results showed that some of the cells in LPS group were pyknotic and hyperemic, and the inflammatory cells increased. The above pathological changes significantly reduced in LPS+Nar50 group and LPS+Nar100 group compared with LPS group, and the reduction was more significant in LPS+Nar100 group. Conclusion: STI can be used to evaluate early myocardial injury and Nar pretreatment on reducing myocardial injury in sepsis rats.