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

Abstract

In an in vivo 5-week initiation assay model, chemical hepatectomy by hepato-toxicant administration was utilized as a cell proliferation stimulus as an alternative to the two-thirds partial hepatectomy. The study investigated the effect of an intraperitoneal (i.p.) injection of D-galactosamine (D-gal) for this purpose in a medium-term liver bioassay, with a further focus on cell proliferation kinetics and cytochrome P450 (CYP) expression. In experiment I, cell proliferation in rat liver after a single administration of D-gal (700 mg kg(-1), i.p.) was analysed by the bromodeoxyuridine (BrdU) labeling method, and CYP isozymes were quantified by immunoblotting. In experiment II, the induction of glutathione S-transferase placental form (GST-P) positive foci by 1,2-dimethylhydrazine (DMH) was evaluated in a modified in vivo 5-week initiation assay model. At 84 hours after single administration of d-gal (i.p.) the BrdU index was markedly elevated (27.5% +/- 9.5%). Although CYP 2E1 and 1A2 apoprotein contents decreased transiently to less than 20% of the control level, subsequently they recovered to 60% and 40% of the control level, respectively, at 84 hours. Induction of GST-P positive foci in the group given DMH at 84 hours after a single administration of d-gal was significantly greater than in the control group, correlating with the kinetics of cell proliferation. In conclusion, the sensitivity of the present initiation assay using D-gal i.p. is high, so that D-gal i.p. can be considered an effective cell proliferation stimulus.

Combination of Selenium and Three Naturally Occurring Antioxidants Administration Protects d-Galactosamine-Induced Liver Injury in Rats

“…Chemical hepatotoxicant administration can alternatively be utilized as a cell proliferation stimulus in the partial hepatectomy. Dgalactosamine could be considered an effective cell proliferation stimulus [37]. In our study, the decrease of hepatocyte proliferation in the group treated with D-GaIN and antioxidant combination may be related to the delay in the initiation of triggering of the regeneration process because of the antioxidants.…”

Deficiency of p38α in macrophage ameliorates d‐galactosamine/TNF‐α‐induced acute liver injury in mice

“…A high dose of GalN is known to induce apoptosis of hepatocytes in rat and mouse, which is evidenced by histochemical observations, DNA laddering, and caspase 3 activation [2][3][4]. Upon GalN injury, progenitor cells proliferate and differentiate into mature hepatocytes [6], while hepatocytes proliferate to restore the liver mass after GalN treatment [6][7][8]. Liver regeneration is known to be important for survival after GalN Abbreviations ALI, acute liver injury; ALT, alanine aminotransferase; AST, aspartate aminotransferase; BMDM, bone marrow-derived macrophage; CCL5, chemokine (C-C motif) ligand 5; CDK, cyclin-dependent kinase; CXCL, C-X-C motif chemokine ligand; ERK, extracellular signal-regulated kinase; GalN, D-galactosamine; H&E, hematoxylin and eosin; IFN-γ, interferon-γ; IL, interleukin; JNK, c-Jun N-terminal kinase; KC, Kupffer cell; KO, knockout; LPS, lipopolysaccharide; MAPK, mitogen-activated protein kinase; MCP-1, monocyte chemoattractant protein-1; MDM, monocyte-derived macrophage; NPC, nonparenchymal cell; PM, peritoneal macrophage; TNF-α, tumor necrosis factor-a; TUNEL, terminal deoxynucleotidyl transferase dUTP nick end labeling.…”

“…Liver regeneration is known to be important for survival after GalN overdose, which involves proliferation of both progenitor cells and hepatocytes. Upon GalN injury, progenitor cells proliferate and differentiate into mature hepatocytes [6], while hepatocytes proliferate to restore the liver mass after GalN treatment [6][7][8]. Liver has the largest population (80-90%) of macrophages, which play important roles in the proper regulation of immune responses.…”

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

“…Human exposure to environmental carcinogens is usually limited to low concentrations and human are generally exposed to such carcinogens over a long-term period [1,7,49]; therefore, multiple low-dose administration would be expected to be superior to single high-dose administration for extrapolation to carcinogenesis in humans. Generally, previous assay models using a cell proliferation stimulus tested only single or multiple doses over 1-day administration of test chemicals because the induction of hepatocyte proliferation could be maintained only for approximately 1 day [2,39]. In the current study, hepatocyte proliferation activity in 4-weekold rats was significantly higher than that in 8-week-old rats and continued at high levels until 4.5 weeks of age in experiment I, and the induction of GST-P-positive foci by 4-day divided doses of DMH was approximately equal to that with the same total single dose of DMH in experiment II.…”

“…The reaction mixture comprising 5 l of 20-mM testosterone, 50 l of 10-mM NADPH, and phosphate buffer (0.1 M, pH 7.4) was prepared to a total volume of 450 l. Immunohistochemistry: The avidin-biotin complex method has been used to demonstrate BrdU-labeled hepatocytes, in the S-phase of the cell cycle, and GST-P-positive foci [2,20]. The sections were incubated with peroxidaseblocking solution (DAKO Cytomation Inc., Carpinteria, CA, U.S.A.) for 5 min to block any endogenous peroxidase activity, and incubated with Protein block serum-Free (DAKO Cytomation Inc.) for 10 min for nonspecific binding.…”