中文摘要：

目的 通过建立辐射诱导急性肝损伤动物模型,探讨31P MRS检测所得的肝内三磷酸腺苷（ATP）含量变化与肝细胞病理损伤之间的关系.方法 将30只家兔按单纯随机抽样法分别接受1次性5、10、20 Gy不同剂量辐射,在辐射后24 h行31P MRS和肝功能检查,随后作病理检查.根据肝细胞病理损伤程度,将其分为轻、中、重度肝损伤3组.并与10只健康家兔检测结果作正常对照分析.以磷酸一脂（PME）、无机磷（Pi）、磷酸二脂（PDE）和β-ATP的信号强度作为研究代谢物（以β-ATP为主）,所有磷代谢物相对值均为校正相对值.不同程度急性肝病理损伤兔肝31P MRS检查结果行方差分析,差异有统计学意义后两两比较采用SNK法.结果 正常对照组（10只）及轻度（12只）、中度（11只）、重度（7只）肝损伤组肝内ATP相对量分别为1.83±0.33、1.58±0.25、1.32±0.07和1.02±0.18,各组间差异有统计学意义（F=22.878,P＜0.01）,组内两两比较,差异均有统计学意义（P值均＜0.05）;且随着肝病理损伤程度的加重,ATP相对量呈逐渐下降.PDE相对量值变化无规律性,而不能对放射性肝损伤作出正确评价.β-ATP峰随着肝损伤的加重而波峰下面积呈逐渐减少改变.结论 ATP相对量水平可准确反映家兔急性辐射性肝病理损伤及其严重程度,肝内ATP下降可作为急性肝损伤的生物标记.

英文摘要：

Objective To study the relationship between ATP level changes detected by hepatic 31P MRS with the pathologic changes of liver in rabbits and to investigate the diagnostic value of ATP level changes in acute hepatic radiation injury. Methods A total of 30 rabbits received different radiation doses （ ranging from 5,10,20 Gy） to establish acute hepatic injury models. Blood hepatic function tests, 31P MRS and pathological examinations were carried out 24 h after irradiation The degree of injury was evaluated according to hepatocyte pathology. Ten healthy rabbits served as controls. The MR examination was performed on a 1.5 T imager using a 1H-31P surface coil with 2D chemical shift imaging technique. The relative quantities of phosphomonoesters （PME）, phosphodiesters （PDE）, inorganic phosphate （Pi） and adenosine triphosphate （ATP） were measured. Analysis of variance was used to compare the results of 31P MRS and histopathology under various acute hepatic radiation injuries, and SNK was used further to conduct comparison between each other if there was significant difference. Results The ATP relative quantification in control（ n= 10）, mild （ n = 12）, moderate （ n = 11 ）, and severe （ n = 7 ） injury groups according to pathological grading were 1.83 ± 0. 33, 1.58 ± 0. 25, 1.32 ± 0. 07 and 1.02 ± 0. 18, with significant differences among them （F =22. 878 ,P 〈0. 01 ）, and it decreased progressively with the increased degree of injury. The PDE index showed no significant trend for the evaluation of hepatic radiation injury. The area under the peak of β-ATP decreased with the increased severity of radiation injury. Conclusions The relative quantification of hepatic ATP levels can reflect the pathological severity of acute hepatic radiation injury. The decreasing hepatic ATP levels may be used as biomarker of acute liver injury following radiation.