Objective: To investigate the biochemical metabolic changes detected by phosphorus-31 MR spectroscopy ((31)P MRS) with pathologic changes in the liver of fasting rabbits.
Methods: A total of 22 rabbits were under the starvation up to death to establish animal models. Hepatic (31)P MRS was performed in different period of 10 rabbits including normal condition, over-starvation, agonal condition and death after 30 min. Other 9 rabbits were divided into three type including over-starvation, agonal condition and death group with 3 rabbits in each group, and 3 healthy rabbits served as controls. All the 12 rabbits were sacrificed for the hepatic pathological examination. The MR examination was performed on a 1.5 T imager using a 1H/31P surface coil by the 2D chemical shift imaging technique. The relative quantities of phosphomonoesters (PME), phosphodiesters (PDE), inorganic phosphate (Pi) and adenosine triphosphate (ATP) were measured.
Results: All the relative quantification of phosphorus metabolites were changed significantly from starvation to death (X(2)=23.13-35.41, P<0.01). The relative quantifications of ATP of normal condition, over-starvation, agonal condition and death were 2.54 +/-0.53, 1.73 +/-0.14, 0.88 +/-0.23 and 0.05 +/-0.08, respectively (rs=1.0, P<0.01). The relative quantifications of PDE from normal to death were 1.25 +/-0.54, 2.76 +/-0.23, 3.33 +/-0.49 and 3.87 +/-0.43, respectively, and those of Pi were 0.42 +/-0.02, 0.65 +/-0.05, 0.89 +/-0.15 and 0.99 +/-0.08, respectively (rs=1.0, P <0.01). The relative quantifications of PME were also significantly changed (rs=0.4, P=0.6). The pathologic changes of normal condition, over-starvation, agonal condition and death: decreased size of hepatocytes, loss of cell number, cellular swelling, degeneration and cell necrosis or hepatic hemorrhage became more and more pronounced.
Conclusion: (31)P MRS can monitor dynamic changes of relative quantification of phosphorus metabolites, which are correlated with the pathological severity of acute hepatic injury by fasting.