Two-dimensional database of mouse liver proteins: Changes in hepatic protein levels following treatment with acetaminophen or its nontoxic regioisomer 3-acetamidophenol

Overdose of acetaminophen (APAP) causes acute hepatotoxicity in rodents and man. The mechanism underlying APAP-induced liver injury remains unclear, b ut experimental evidence strongly suggests that activation of APAP and subs equent formation of protein adducts are involved in hepatotoxicity. Using p roteomics technologies, we constructed a two-dimensional protein database f or mouse liver, comprising 256 different gene products and investigated the proteins affected after APAP-induced hepatotoxicity. Adult male mice recei ved a single dose of APAP (100 or 300 mg/kg) or its nontoxic regioisomer 3- acetamidophenol (AMAP, 300 mg/kg). The extent of liver damage was assessed 8 h after administration by increased liver enzyme release and histopatholo gy. Changes in the protein level were studied by comparison of the intensit ies of the corresponding spots on two-dimensional (2-D) gets. The expressio n level of about 35 of the identified proteins was modified due to treatmen t with APAP or AMAP. The observed changes were usually in the order of 10-5 0% of the control value and were more marked in the high- than in the low-d ose of APAP-treated animals. Most of the changes caused by AMAP occurred in a subset of the proteins modified by APAP. Many of the proteins showing ch anged expression levels are either known targets for covalent modification by N-acetyl-p-benzoquinoneimine (NAPQI) or involved in the regulation of me chanisms that are believed to drive APAP-induced hepatotoxicity.