Endotoxin affects the expansion modes of liver macrophages after partial hepatectomy.
We studied the effect of increased endotoxin levels on the expansion modes of liver macrophages after two-thirds partial hepatectomy using anti-endotoxin polymyxin B. The expansion consists of dual modes: local proliferation and immigration. Local proliferation of mature cells was evaluated by the S-phase proportion measured by flow cytometric DNA analysis. This proportion (11.8 +/- 1.3% before hepatectomy) decreased to 6.0 +/- 1.1% at 12 h and reached a maximum of 21.9 +/- 2.7% on the 5th day after hepatectomy. In polymyxin B treated rats, the proportion reached a maximum of 21.1 +/- 1.6% at 48 h without any preceding decrease. Immigration of macrophage precursors was evaluated by the decreasing proportion of latex beads-containing cells that were marked as resident liver macrophages by injection of latex beads before hepatectomy. This proportion (98.7 +/- 0.2% before hepatectomy) was significantly decreased to 90.5 +/- 1.6% at 48 h. In polymyxin B treated rats, however, the proportion showed no significant decrease within 3 days. These results indicate that endogenous endotoxin, which suppresses the local proliferation and promotes extrahepatic recruitment, regulates the number of liver macrophages in regenerating rat liver.
Second Department of Internal Medicine, Nagoya University School of Medicine, Japan.
I
I
Nakano
M
M
Imoto
Y
Y
Fukuda
Y
Y
Koyama
T
T
Satake
D000818:Animals; D002455:Cell Division; D002465:Cell Movement / Q000502:physiology; D004247:DNA / Q000032:analysis; D004731:Endotoxins / Q000494:pharmacology*; D005434:Flow Cytometry; D006498:Hepatectomy / Q000379:methods; D007728:Kupffer Cells / Q000166:cytology*; D008115:Liver Regeneration / Q000502:physiology*; D008297:Male; D011112:Polymyxin B / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
D004731:Endotoxins; D004247:DNA; D011112:Polymyxin B