The Effects of Allyl Alcohol-induced Cell Proliferation for Detection of Initiation Activities of Chemicals in Rat Liver.

Abstract

Abstract:The effect of allyl alcohol (AA) administration on the induction of glutathione S-transferase placental form (GST-P) positive foci in medium term liver bioassay was investigated for the detection of initiation activities. In experiment I, the cell kinetics of rat liver after AA administration (0.1 ml/kg, i.g.) was analyzed by the 5-bromo-2'-deoxyuridine (BrdU) labeling method. Cytochrome P450 (CYP) 2E1 protein, which is involved in the bioactivation of 1,2-dimethylhydrazine (DMH), was quantificated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the immunohistochemical localization of CYP2E1 was also examined. In experiment II, the induction of GST-P positive foci by DMH was evaluated in a modified in vivo five-weeks initiation assay model using AA treatment to induce cell proliferation. AA induced periportal necrosis and led to regenerative proliferation. High BrdU labeling indices were observed from 24 h to 48 h (5-6%). CYP2E1 protein contents decreased transiently to approximately 40% of control after AA administration, but subsequently recovered to the control level. Immunohistochemically, CYP2E1 was localized in the centrilobular area each time, and the staining pattern was constant. The numbers and areas of GST-P positive foci were highly induced in the animals given DMH at 12 h after AA administration, compared to before the high BrdU labeling term. There was a correlation between the kinetics of cell proliferation and the induction of GST-P positive foci. Although CYP2E1 decreased after AA treatment, it is likely that the enzyme remained enough to metabolize DMH. These results suggest that AA-induced cell proliferation is an effective proliferative stimulus in medium-term initiation assay. (J Toxicol Pathol 2002; 15: 95-102)

Intraperitoneal injection ofd-galactosamine provides a potent cell proliferation stimulus for the detection of initiation activities of chemicals in rat liver

“…In previous studies, hepatotoxic chemicals, including CCl 4 , AA and D-gal, were used to stimulate cell proliferation for the detection of initiation activity (Kobayashi et al, 1997;Sakai et al, 2000Sakai et al, , 2001Sakai et al, , 2002aOkamura et al, 2002). Although each hepatotoxic chemical induces necrosis of the hepatocytes by a different mechanism of liver injury, proliferation of hepatocytes is induced in all cases.…”

“…AA is converted by alcohol dehydrogenase into acrolein, which is a highly reactive aldehyde and principally causing periportal necrosis (Badr, 1991;Lee et al, 1996). However, BrdU labeling indices following necrosis after AA administration are relatively low (Okamura et al, 2002).…”

“…Although intragastric injection of carbon tetrachloride (CCl 4 ), allyl alcohol (AA) or high dose D-galactosamine (D-gal) were found to induce cell proliferation in previous studies, the level of induction was much lower than with PH. Accordingly, induction of GST-P positive foci was also markedly less (Kobayashi et al, 1997;Sakai et al, 2000Sakai et al, , 2001Sakai et al, , 2002aOkamura et al, 2002).…”

“…Therefore, in vivo 5-week initiation assay models using hepatotoxic chemicals to provide the proliferation stimulus have been developed (Kobayashi et al, 1997;Sakai et al, 2000Sakai et al, , 2001Sakai et al, , 2002aOkamura et al, 2002). Although intragastric injection of carbon tetrachloride (CCl 4 ), allyl alcohol (AA) or high dose D-galactosamine (D-gal) were found to induce cell proliferation in previous studies, the level of induction was much lower than with PH.…”

Detection of Initiation Activity of 1,2-Dimethylhydrazine in in vivo Medium-Term Liver Initiation Assay Ssytem using 4-Week-Old Rats without Hepatocellular Proliferative Stimuli during the Test Chemical Treatment Period

“…Chemical hepatectomy (CH) and the fasting/refeeding method are very simple as compared with PH, but these methods also entail certain problems. Hepatotoxicants such as carbon tetrachloride (CCl 4 ), allyl alcohol, and d-galactosamine have been used for CH; however, although they induced hepatocyte proliferation, the induction of GST-Ppositive foci in the medium-term liver initiation assay model with these cell proliferation stimuli was lower than that with PH in previous studies [27,33,[39][40][41]. The reason is possibly that the induction of hepatocyte proliferation after the administration of these hepatotoxicants was lower than that after PH; moreover, when hepatocyte proliferation activity was increased, the hepatic metabolic enzymes causing metabolic activation of procarcinogen were markedly decreased by hepatotoxicity of these hepatotoxicants.…”