Segmental cholangitis impairs hepatic regeneration capacity after partial hepatectomy in rats

Abstract

Background: Patients with hilar cholangiocarcinoma or hepatolithiasis often develop segmental cholangitis (SC), but it is unclear whether hepatectomy for patients with SC can be performed safely.

Methods: Rats were subjected to segmental bile duct ligation (SBDL) with LPS (SC group) or a saline (Sham group) infusion into the bile duct of the ligated lobes. The rats were sacrificed at 3, 24 and 48 h after the SBDL. For another experiment, the rats were subjected to partial hepatectomy (PHx) for the ligated lobes. Hepatic regeneration rates and the expression of regeneration-associated genes were evaluated.

Results: In the SC group, severe parenchymal damage was observed in the acute phase (3 h). Altered gene expression in the liver in response to biliary infection occurred not only in the infected lobes but also in the non-infected lobes. In the rats of the SC group, both the hepatic regeneration rate and serum HGF levels were significantly lower than in the Sham group.

Conclusion: These results clearly demonstrate that SC impairs the regeneration capacity of the contralateral remnant liver. Therefore, hepatectomy should be avoided for patients with SC even if it occurs in the part of the liver to be resected.

Figure 1

(a) Schema showing the segmental bile duct ligation (SBDL) procedure and the injection of saline or lipopolysaccharide (LPS) (concentration; 1 mg/ml) into the bile duct. (b) Schedules of experiment 1 (SC-Induction) and 2 (Hepatectomy after SC-Induction)

Figure 2

Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels at 3, 24 and 48 h after the segmental bile duct ligation (SBDL). Blood samples were obtained from the abdominal aorta. Data are means ± SE of eight animals in each group. *P < 0.05 vs. Sham by t-test

Figure 3

The gene expression of inflammation-associated factors (IL-6, TNF-α, iNOS, and NF-κB) in the livers from both the segmental bile duct ligation (SBDL) lobes and the non-SBDL lobes at 3, 24, and 48 h after the SBDL. Liver samples were harvested at each time point (3, 24 and 48 h) from both the non-SBDL lobes and the SBDL lobes. The average expression level of the non-SBDL lobes in the Sham group at each time point was set to 1.0, and other data were adjusted to this baseline. Data are means ± SE of eight animals in each group. *P < 0.05 vs. Sham by t-test. IL-6, interleukin-6; TNF-α, tumour necrosis factor-α; iNOS, inducible nitric oxide synthase; NF-κB, nuclear factor-κB

Figure 4

Serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels on day 1 after partial hepatectomy (PHx) which was performed at 3, 24 and 48 h after the segmental bile duct ligation (SBDL). Data are means ± SE of eight animals in each group. *P < 0.05 vs. Sham by t-test

Figure 5

(a) Percentage of the newly regenerated liver weight (hepatic regeneration rate) on day 1 after the partial hepatectomy (PHx), which was performed at 3, 24 and 48 h after the segmental bile duct ligation (SBDL). Data are means ± SE of eight animals in each group. *P < 0.05 vs. Sham by t-test. (b) Survival rate of rats after the PHx, which was performed at 3 h after the SBDL. Statistical difference between the groups was determined by Kaplan–Meier survival analysis. *P < 0.05 vs. Sham

Figure 6

(a) Mitotic index evaluated by histological examination on day 1 after the partial hepatectomy (PHx), which was performed at 3, 24 and 48 h after the segmental bile duct ligation (SBDL). Data are means ± SE of eight animals in each group. *P < 0.05 vs. Sham by t-test. (b) Representative micrographs of the remnant liver on day 1 after the PHx, which was performed at 3 h after the SBDL (haematoxylin and eosin staining). Arrows indicate the hepatocytes with mitosis (original magnification × 200). (c) The gene expression of hepatic regeneration-associated factors (hepatic regeneration promoters, HGF and EGF; hepatic regeneration inhibitors, TGF-β and IL-1β) in the liver of the remnant lobes on day 1 after the PHx, which was performed at 3 h after the SBDL. The average expression level of the Sham group's data at each time point was set to 1.0, and other data were adjusted to this baseline. Data are means ± SE of eight animals in each group. *P < 0.05 vs. Sham by t-test. HGF, hepatocyte growth factor; EGF, epidermal growth factor; TGF-β, transforming growth factor-β; IL-1β, interleukin-1β

Figure 7

Serum hepatocyte growth factor (HGF) and interleukin-1β (IL-1β) levels at 3 h after the segmental bile duct ligation (SBDL) (before PHx) and on day 1 after the partial hepatectomy (PHx) which was performed at 3 h after the SBDL. Blood samples were obtained from the abdominal aorta. Serum levels of HGF and IL-1β were determined using an enzyme-linked immunosorbent assay (ELISA). Data are means ± SE of eight animals in each group. * P < 0.05 vs. Sham by t-test

Figure 8

(a) Immunohistochemistry forα-smooth muscle actin (α-SMA) protein in the liver at 3 h after the segmental bile duct ligation (SBDL) (original magnification × 400). (b) The gene expression of α-SMA in the livers from both the SBDL lobes and the non-SBDL lobes 3 h after the SBDL. The average expression level of the non-SBDL lobes in the Sham group at each time point was set to 1.0, and other data were adjusted to this baseline. Data are means ± SE of eight animals in each group. *P < 0.05 vs. Sham by t-test