Disrupted NF- kappa B activation after partial hepatectomy does not impair hepatocyte proliferation in rats.

Aim: To analyze the effects of NF- kappa B inhibition by antioxidant pyrrolidine dithiocarbamate (PDTC) or TNF inhibitor pentoxifylline (PTX) on liver regeneration after partial hepatectomy (PH).

Methods: Saline, PDTC or PTX were injected 1 h before PH and rats were killed at 0.5 and 24 h after PH.

Molecular events associated with accelerated proliferative response in rat livers when partial hepatectomy is preceded by a sham operation.

Background: When a sham operation is performed 6 h before partial hepatectomy (PH), the regenerative response is accelerated suggesting that sham operation itself contributes to cellular events leading to proliferation.

Materials And Methods: In order to examine the mechanisms implicated in this acceleration, we compared the activation of several factors associated with the progression through the cell cycle at various times after PH and after PH preceded by sham operation (S6 h + PH). The effect of a single sham (S) and two combined sham operations (S6 h + S) was also examined.

Retrorsine: a kinetic study of its influence on rat liver regeneration in the portal branch ligation model.

Background: Retrorsine, a naturally occurring pyrrolizidine alkaloid, impairs liver regeneration after partial hepatectomy by mechanisms that are still unclear.

Aim: The aim of the study was to clarify the influence of retrorsine on cell cycle progression in the regenerating liver lobes of rats after portal branch ligation (PBL).

Methods: Liver weight, protein and DNA contents, DNA synthesis (5'-bromodeoxyuridine (BrdU) incorporation) and cellular levels of Cyclin E, CDK-2, CDK-4 and proliferating cell nuclear antigen (PCNA) were assessed before and 24, 48, 72 and 168 h after PBL.

Steatosis is not sufficient to cause an impaired regenerative response after partial hepatectomy in rats.

Background/aims: Fatty liver is known to be associated with increased mortality and morbidity after liver resection. The ability of fatty liver to regenerate after two-thirds partial hepatectomy was studied in three different models of steatosis in rats: obese Zucker rats, orotic acid-fed Wistar rats and Wistar rats fed a methionine-low, choline-deficient diet.

Methods: Liver regeneration was assessed 24 h after partial hepatectomy by bromodeoxyuridine incorporation (immunohistochemistry), proliferating cell nuclear antigen, cyclin E and cyclin-dependent kinase 2 protein expression (Western blot analysis) and cyclin-dependent kinase 2 activity (kinase assays using histone H1 as a substrate).

Expression of presumed specific early and late factors associated with liver regeneration in different rat surgical models.

Experiments performed on the portal branch ligation (PBL) model indicate that early changes observed after surgery are not related to the regenerative process because they also occur in atrophying lobes. To further confirm the lack of specificity of the early events and to exclude the influence of circulatory factors released by proliferating lobes on their occurrence, we investigated this response after sham operation (SO) and portacaval shunt (PCS), a model characterized by liver atrophy. We also attempted to determine expression of later events associated specifically with regeneration, ie, expression of p53 or c-Ha-ras, or inhibition of proliferation, ie, interleukin-1beta (IL-1beta) and transforming growth factor-beta1 (TGF-beta1) after partial (PH) and temporary partial (TPH) hepatectomy, SO and PCS.