Inhibition of hepatic energy metabolizing enzymes in murine model exposed to diisononyl phthalate


Background and objectives: Diisononyl phthalate (DINP) is a class of phthalates and phthalates are known to be metabolism disrupting chemicals (MDCs). Numerous MDCs, to which humans are exposed, have an effect on every aspect of energy transduction. They affect the liver by impairing insulin secretion in pancreatic cells and altering the liver’s insulin-dependent glucose metabolism. Methods: For this study, eighteen male albino rats weighing 200±20g were randomly assigned to three groups (of six rats each) and followed for a 14-days period. The groups were: group A or control which was given Tween-80 orally, group B or DINP1 group which was given 20 mg/kg b.wt. DINP, and Group C or DINP2 group which received 200 mg/kg b.wt. DINP. The rats were then sacrificed, their livers were removed, and the glycolytic and oxidative phosphorylation enzyme activities were evaluated. Results: Activities of the glycolytic, tricarboxylic acid cycle and electron transport chain enzymes under investigation were significantly down-regulated with severity observed in decreased activities of hepatic oxidative phosphorylation enzymes when compared with control (P<0.05). Hepatic tissue sections of 20 and 200mg/kg DiNP group revealed distorted cytoarchitecture of hepatocytes ranging from histocellular disarrangement to vaocular changes suggestive of loss of liver integrity or fibrosis. Conclusions: Finally, DINP exposure impairs hepatic energy transduction enzymes as evident in down-regulation of the various enzymes of energy metabolism under investigation and this may invariably be a good tool for diagnosis for hepatic energy impairment as seen in some disease conditions.