Quantitative image cytometry of hepatocytes expressing gamma-glutamyl transpeptidase and glutathione S-transferase in diethylnitrosamine-initiated rats treated with phenobarbital and/or phthalate esters.

Abstract

Image cytometry was used to quantify the volume of liver expressing two histochemical markers associated with neoplasia, gamma-glutamyl transpeptidase (GGT) and the placental isozyme of glutathione S-transferase (GST-P). Rats were treated with diethylnitrosamine (DENA) followed by phenobarbital (PB), di(2-ethylhexy1)phthate (DEHP), or di-n-octylphthalate (DOP) for 26 weeks. In one series, PBtreated rats were given 2.0%, 0.5%, or 0.1% DEHP in the feed. GGT expression was detected diffusely throughout the liver parenchyma in several treatment groups so that any enhanced expression in altered foci (AF) and nodules (N) was not apparent. GST-P was detected only in AF and N. GST-P may represent a second genetic alteration, as GST-P' AF and N also expressed GGT but not the reverse. The peroxisome

Cytokeratin 8/18 is a Useful Immunohistochemical Marker for Hepatocellular Proliferative Lesions in Mice

“…These findings on hepatocellular carcinomas indicate that some of the carcinomas were negative for GGT. As described above, the result of our study also confirmed the disadvantage pointed out by the previous workers that hepatocellular proliferative lesions observed in HEstained sections could not be always detected in GGT histochemistry [6,7].…”

“…Furthermore, GGT-negative adenomas were noted in 5 of 6 mice (83%). These findings indicate that hepatocellular adenomas observed in HEstained sections could not be always detected in GGT histochemistry, as demonstrated by the previous histochemical study in rats [6]. Regarding hepatocellular carcinomas stained with HE, 3 of 6 mice (50%) had hepatocellular carcinomas, while 1 of 6 mice (17%) and 3 of 6 mice (50%) had GGT-positive carcinomas and GGT-negative carcinomas, respectively.…”

“…Whereas, it has been suggested that GST-P may be a superior marker for biochemically altered hepatocellular foci in rats, since GST-P expression appears to be limited to hepatocellular foci and tumors in rats, with very little expression occurring in normal liver parenchyma [26,28,30]. On the other hand, it is generally recognized that GST-P is not immunohistochemically reactive for liver preneoplastic and neoplastic lesions of mice and there is a disadvantage that almost all the proliferative lesions are not always stained with GGT [6]. In the present study, all treated mice had GGT-positive foci, but the number of GGT-positive foci was lower than that of hepatocellular foci observed in HE-stained sections in Experiment I.…”

Automated Double Labeling of Proliferation and Apoptosis in Glutathione S-transferase-positive Hepatocytes in Rats

“…Automating the quantitation of BrdU-or TUNEL-labeled cells in normal hepatocytes from rat and mouse liver is described, as well as image analysis of hepatocytes expressing GSTP (Carter et al 1992;Soames et al 1994;Ringer 1995,1996), but automated quantitation of these phenomena within rat hepatic foci has not. Use of automated double labeling techniques described here will permit rapid and accurate assessments of proliferation and apoptosis and may aid efforts aimed at automating the quantitation of the net growth potential of preneoplastic and neoplastic lesions.…”

Peroxisome proliferator-activated receptor γ ligands suppress liver carcinogenesis induced by diethylnitrosamine in rats

“…Immunohistochemical staining was performed on sections by the peroxidaseantiperoxidase method, using the antibody against the rGST P. Sections were counterstained with haematoxylin. The number of rGST P-positive foci (consisting of single to several GST P positive cells, indicating preneoplastic lesions) was expressed as per cm 2 of liver sections [16] .…”