Expression data of liver tissues from rats with and without methapyrilene treatment

We investigated a drug-induced liver injury (DILI) model in rats induced by methapyrilene (MPy) administration. MPy, a former antihistamine and anticholinergic drug, was withdrawn in the 1970ties due to its ability to initiate hepatocarcinogenesis and is now used to induce hepatobiliary injury and biliary epithelial cell hyperplasia. Male Wistar rats (810 weeks old, weighing 170200 g) were randomly assigned to three dosing groups (n=6 per group and time-point) and dosed with MPy at 0, 30 and 80 mg/kg/day by oral gavage. After 4, 8 or 15 days, or after 14 days followed by a recovery period of 10 days (day 24) rats were sacrificed. Increased levels of ALAT, ASAT, AP and -GT as well as bili-t and total bile acids indicated liver damage (AP and GT indicating biliary effects). They were detectable on day 7 at the high dose of 80 mg/kg MPy and persisted until day 15 at end of treatment. Histopathologically, vacuolation and necrosis of the hepatocytes (predominantly in the periportal region) were seen starting on day 3 - especially in animals treated with 80 mg/kg MPy. These findings were accompanied by periportal mononuclear inflammatory cell filtration. Bile duct proliferation, bile duct hyperplasia and increased numbers of mitoses of hepatocytes were evident at all treatment time points. The frequency and severity of these findings increased with dose and duration of the treatment. Gene expression analysis in liver tissues revealed highly significant transcriptional changes in the high dose group, detectable on day 4 and intensifying over time. Besides genes associated with apoptosis (CASP4, CASP12), detoxification (CYB4B) and proliferation (p21, CCNG1) several were related to bile acid metabolism or transport. For example, bile acid exporters OATP1, NTCP, OATP4 and MOAT1/ OATPB as well as the putative bile acid metabolizing enzymes AMACR, BAAT and ACOX2 were found down regulated in response to MPy treatment. In contrast, mRNAs encoding putative bile acid importers MRP2 and ABCC4 / MRP4 were found up regulated. Most of the deregulated levels returned to control values during the recovery phase except OATP1, MOAT1/ OATPB, which remained slightly elevated. Interestingly, OATP4 followed an inverse trend of deregulation after 10 days of recovery, presumably due to overcompensation. Overall, the expression changes found associated with bile acid metabolism or transport could be linked to detected bile acid level alterations in liver and plasma.

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Slopianka M, Herrmann A, Pavkovic M, Ellinger-Ziegelbauer H, Ernst R, Mally A, Keck M, Riefke B