Abstract
The purpose of this study was to identify the mechanism(s) whereby acute ethanol exposure inhibits hepatic regenerative activity in the rat. Adult, male, Sprague-Dawley rats (200-250 g) were randomized to receive either ethanol (1 g/kg I.P. q 4 h) or an equal volume of saline (controls) for 24 h beginning 1 h prior to a 70% partial hepatectomy (PHx). At 0, 3, 6, 12 and 24 h post-PHx, rats were sacrificed (N = 4-6/group), and the expression of the following genes associated with inhibition of hepatocyte proliferation were documented; p53, p21, transforming growth factor-β1 (TGF-β1) and gamma aminobutyric acid transport protein (GABA-TP). Inhibition of hepatic regenerative activity was confirmed by 3H-thymidine incorporation into hepatic DNA at 24 h post-PHx. The results of the study revealed that in ethanol-treated rats, DNA synthesis was inhibited by 37% when compared to saline-treated controls (p < 0.01). Regarding suppressor gene expression, both p21 and TGF-β1 mRNA expression in ethanol-treated rats were similar to those obtained in saline-treated controls. Although p53 mRNA expression differed in the two groups, in the ethanol-treated group, p53 mRNA expression was decreased rather than increased (relative to controls) at 24 h post-PHx which would not be in keeping with inhibition of DNA synthesis. GABA-TP mRNA was strongly expressed prior to PHx in both ethanol- and saline-treated rats. Following PHx, GABA-TP mRNA expression decreased in both groups but remained low in the saline-treated group while returning to pre-PHx values in ethanol-treated rats. In summary, the results of this study indicate that the inhibitory effects of ethanol on hepatic regeneration are not associated with significant or the appropriate changes in mRNA expression of the p53, p21 or TGF-β1 suppressor genes. On the other hand, transcriptional changes in GABA-TP gene expression post-PHx are in keeping with an inhibitory effect of GABA on hepatic regeneration.
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References
Cox LS, Lane DP: Tumour suppressors, kinases and clamps: How p53 regulates the cell cycle in response to DNA damage. BioEssays 17: 501–508, 1995
Donehower LA, Bradley A: The tumor suppressor p53. Biochim Biophys Acta 1155: 181–205, 1993
Lin D, Shields MT, Ullrich SJ, Appella E, Mercer WE: Growth arrest induced by wild-type p53 protein block cells prior to or near the restriction point in late G1-phase. Proc Natl Acad Sci USA 89: 9210–9214, 1992
Vogelstein B, Kinzler KW: p53 function and dysfunction. Cell 70: 523–526, 1992
Hollstein M, Sidransky D, Vogelstein B, Harris CC: p53 mutations in human cancers. Science 253: 49–53, 1991
Albrecht JH, Meyer AH, Hu MY: Regulation of cyclin-dependent kinase inhibitor p21 gene expression in hepatic regeneration. Hepatology 25: 557–563, 1997
Hui A-M, Kanai Y, Sakamoto M, Tsuda H, Hirohashi S: Reduced p21WAF1/CIP1 expression and p53 mutation in hepatocellular carcinomas. Hepatology 25: 575–579, 1997
Ehrenfried JA, Ko TC, Thompson EA, Evers BM: Cell cyclemediated regulation of hepatic regeneration. Surgery 122: 927–935, 1997
Harper JW, Adami GR, Wei N, Keuomarsi K, Elledge SJ: The p21 Cdk-interaction protein CIP1 is a potent inhibitor of G1 cyclindependent kinases. Cell 75: 805–816, 1993
Serfas MS, Goufman E, Feuerman MH, Gartel AL, Tyner AL: p53-independent induction of p21WAF1/CIP1 expression in pericentral hepatocytes following carbon tetrachloride intoxication. Cell Growth Diff 8: 951–961, 1997
Barnard JA, Bascom CC, Lyons RM, Sipes NJ, Moses HL: Transforming growth factor β in the control of epidermal proliferation. Am J Med Sci 296: 159–163, 1998
Roberts AB, Flanders KC, Kondaiah P et al.: Transforming growth factor β: Biochemistry and roles in embryogenesis, tissue repair and remodeling, and carcinogensis. Recent Prog Horm Res 44: 157–197, 1988
Russell WE, Coffey RJ Jr, Ouellette AJ, Moses HL: Type β transforming growth factor reversibly inhibits the early proliferative response to partial hepatectomy in the rat. Proc Natl Acad Sci USA 85: 5126–5130, 1988
Fausto N, Mead JE, Gruppusp PA, Castilla A, Jakowlew SB: Effects of TGF β1 in the liver: Cell proliferation and fibrogenesis. Ciba Found Symp 157: 165–174, 1991
Sugiyama A, Nagaki M, Shidoji Y, Moriwaki H, Muto Y: Regulation of cell cycle-related genes in rat hepatocytes by transforming growth factor β1. Biochem Biophys Res Commun 238: 539–543, 1997
Minuk GY, Gauthier T: The effect of gamma aminobutyric acid (GABA) on hepatic regenerative activity following partial hepatectomy in rats. Gastroenterology 104: 217–221, 1993
Zhang M, Gong YW, Minuk GY: The effects of ethanol and gamma aminobutryic acid alone and in combination on hepatic regenerative activity in the rat. J Hepatol (in press)
Zhang XK, Gauthier T, Burczynski FJ, Wang GQ, Gong Y, Minuk GY: Changes in liver membrane potentials after partial hepatectomy in rats. Hepatology 23: 549–551, 1996
Minuk GY, Gauthier T, Zhang XK, Wang GQ, Pettigrew NM, Burczynski FJ: Ciprofloxacin prevents the inhibitory effects of acute ethanol exposure on hepatic regeneration in the rat. Hepatology 22: 1797–1800, 1995
Nelson MT, Blaustein MP. GABA efflux from synaptosomes: Effects of membrane potential, and external GABA and cations. J Membr Biol 69: 213–223, 1982
Herbison AE: Estrogen regulation of GABA transmission in rat preoptic area. Brain Res Bull 44: 321–326, 1997
Higgins GM, Anderson RM: Experimental pathology of the liver. I: Restoration of the liver of the white rat following partial surgical removal. Arch Pathol 12: 186–202, 1931
Braun L, Mead JE, Panzica M, Mikumo R, Bell GI, Fausto N: Transforming growth factor b mRNA increases during liver regeneration: a possible paracrine mechanism of growth regulation. Proc Natl Acad Sci USA 85: 1539–1543, 1988
Mead JE, Braun L, Martin DA, Fausto N: Induction of replicative competence ('priming') in normal liver. Cancer Res 50: 7023–7030, 1990.
Luk GD: Essential role of polyamine metabolism in hepatic regeneration: Inhibition of deoxyribonucleic acid and protein synthesis and tissue regeneration by difluoromethylornithine in the rat. Gastroenterology 90: 1261–1267, 1986
Minuk GY, Bear CE, Sarjeant EJ: Sodium-independent, bicucullinesensitive [3H]GABA binding to isolated rat hepatocytes. Am J Physiol 252: 642–647, 1987
Minuk GY, Vergalla J, Ferenci P, Jones EA: Identification of an acceptor system for γ-aminobutyric acid on isolated rat hepatocytes. Hepatology 4: 180–185, 1984
Lester BR, Peck EJ Jr: Kinetic and pharmacologic characterization of gamma-aminobutyric acid receptive sites from mammalian brain. Brain Res 161: 79–97, 1979
Allan AM, Harris RA: Acute and chronic ethanol treatments alter GABA receptor-operated chloride channels. Pharmacol Biochem Behav 27: 665–670, 1987
Suzdak PD, Schwartz RD, Paul SM: Ethanol stimulates gammaaminobutyric acid receptor-mediated chloride transport in rat brain synaptoneurosomes. Proc Natl Acad Sci USA 83: 4071–4075, 1986
Ticku MK, Lowrimore P, Lehoullier P: Ethanol enhances GABAinduced 36C1-influx in primary spinal cord cultured neurons. Brain Res Bull 17: 123–126, 1986
el-Deiry WS, Harper JW, O'Conner PM, Velculescu VE, Canman CE, Jackman J, Pietenpol JA et al.: WAF1, a potential mediator of p53 tumor suppression. Cell 75: 817–825, 1993
el-Deiry WS, Harper JW, O'Conner PM, Velculescu VE, Canman CE, Jackman J, Pietenpol JA et al.: Waf1/Cip1 is induced in p53-mediated GI arrest and apoptosis. Cancer Res 54: 1169–1174, 1994
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Zhang, M., Gong, Y. & Minuk, G. The effects of acute ethanol exposure on inhibitors of hepatic regenerative activity in the rat. Mol Cell Biochem 207, 109–114 (2000). https://doi.org/10.1023/A:1007014919003
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DOI: https://doi.org/10.1023/A:1007014919003