INvrvoHEPATOTOXICITY WITH IN WTRO STUDYOF RATS IN COMPARISON HEPATOTOXICITYSCREENING SYSTEM

For thc establishment of a high throughput screening system using primary cell cultures, investigation of elucidatcd toxicities to assess the correlation between in vitro and in vii,o hepatotoxicity is necessary in the safety eva]uation of thc compound. [n the prcvious study, we reported the usability of rat primary cultured hepatocytes for establishment of high throughput screening system. To confirm the reliability of rat primary hcpatocytes culture screening system, we conducted a singlc-dose in vivo study with relatively high dose of hcpatotoxicant in rats using 4 reference compounds (acetaminophen, amiodarone, tetracycline, carbon tetrachloride), and investigated histopathological changes and expression of oxidative stress-related proteins by immunohistochernistry, Wc also carried out a proteomics analysis for estimating the reliable and scnsitive biomarkers. Histopathologica]ly, cumpound-spccific hepatotoxicity was detected at 24 hr after administration in all compounds cxcept amiodarone, which is known to induce phospholipidosis. Immunohistochemically, oxidative strcss-related proteins were increased within 6 hr after administration in all treated groups. Proteomics analysis revealcd several protein biomarkcrs related to oxidative stress and mitochondrial mctabolism-regulation, which had been previoushy dctected by proteomics analysis in in vitro screening system. Oxidative stress-related protcins were considered ag uscful biomarkers of hepatotoxicity; since they were detected by immunohistoehemistry and proteomics analysis prior to appearancc of compound-specifie histopathologica] changes detected by light microscopy. Considering the relevance of in vitro system to in i,i],o system from the aspect of new biomarkers re]ated to the toxicogenomiesftoxicoproteomics, in vitro primary ce[[ culture system would be sut/ficient to detect hepatotoxicity in the ear[y gtage of drug diseover}r.