title: Biphasic activation of liver regeneration-associated signals in an early stage after portal vein branch ligation.
abstract: At an early stage in liver regeneration, a variety of factors including transcriptional factors, proinflammatory cytokines, and proto-oncogenes are activated or expressed. However, these responses are affected by surgical stress in the conventional portal vein branch ligation model (PVL). We sought to determine the net activation of early regeneration-associated signals after PVL using a newly developed non-surgical stress PVL model. Male Wistar rats were assigned into two groups, a stress-PVL (sPVL) model with laparotomy and portal vein branch ligation, and a non-stress-PVL (nsPVL) one subjected to portal vein branch ligation 1 week after laparotomy in which the effects of surgical stress were subsided. The activation of transcriptional factors and expression of immediate early genes were analyzed at an early time point (within 24 h) by Western blotting and RT-PCR, respectively. A monophasic upregulation of nuclear factor-kappaB (NF-kappaB) and phosphorylated-signal transducer and activator of transcription 3 (p-STAT3) peaked at 3h after sPVL was observed. In contrast, the expression pattern of these factors was biphasic (first peak at 0.5-1 h, second peak at 3-6 h) in nsPVL group. The expression pattern of immediate early genes showed a similar trend between sPVL and nsPVL. cDNA array analysis for the non-ligated lobe at 2 h after PVL revealed a much higher gene activation in sPVL than in nsPVL. These results indicate that previously observed activation pattern of regeneration-associated signals after PVL is significantly affected by the effect of laparotomy and our results using nsPVL model may more accurately represent liver regeneration-associated signal pattern.
authors.affiliation: Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Yokoyama
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Yokoyama
authors.forename: Toru
authors.initials: T
authors.lastname: Kawai
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Masato
authors.initials: M
authors.lastname: Nagino
authors.forename: Koji
authors.initials: K
authors.lastname: Oda
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nimura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sokabe
mesh_terms: D000818:Animals; D008099:Liver / Q000473:pathology; D008115:Liver Regeneration / Q000502:physiology*; D008297:Male; D016328:NF-kappa B / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010766:Phosphorylation; D011169:Portal Vein / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D012038:Regeneration; D050796:STAT3 Transcription Factor / Q000378:metabolism; D013696:Temperature; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D016328:NF-kappa B; D050796:STAT3 Transcription Factor