Participation of autophagy in the degeneration process of rat hepatocytes after transplantation following prolonged cold preservation.
Cold ischemia-warm reperfusion injury of liver grafts has been investigated thoroughly, but its underlying mechanism remains poorly understood. Here we show that autophagy is involved not only during cold preservation but also during warm reperfusion following transplantation. Immunohistochemistry using an antibody against LC3, a microtubule associated protein 1 light chain 3 and a marker of autophagosomes, showed dot-like weak staining in hepatocytes of rat liver grafts during cold preservation. Since University of Wisconsin solution for graft preservation lacks amino acids, the induction of autophagy in hepatocytes was similar to that under starvation conditions. Intense immunopositive punctate structures were detected abundantly in the hepatocytes 30 min after the beginning of reperfusion. LC3-positive granules were often co-localized in ED2-positive Kupffer cells at 60 min of the reperfusion phase. The molecular form of LC3 was mainly LC3-II, a membrane-bound form, during reperfusion, especially at 30 min of the phase. Electron microscopic examination demonstrated numerous vacuolar structures in hepatocytes at 30 min of the reperfusion period, while some hepatocytes with such vacuolar structures were present in the sinusoidal lumen. At the late stage of the reperfusion period, Kupffer cells contained phagocytosed cells that possessed numerous autophagic vacuoles/autolysosomes and nuclei with condensed chromatin. Our results showing the presence of autophagic vacuoles/autolysosomes in hepatocytes of liver grafts after the start of reperfusion suggest that warm reperfusion acted as a stress stimulus to hepatocytes. Moreover, the stress response of hepatocytes may be involved in their degeneration process.
Lu
Zhenhui
Z
Department of Surgery and Clinical Oncology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
Dono
Keizo
K
Gotoh
Kunihito
K
Shibata
Masahiro
M
Koike
Masato
M
Marubashi
Shigeru
S
Miyamoto
Atsushi
A
Takeda
Yutaka
Y
Nagano
Hiroak
H
Umeshita
Koji
K
Uchiyama
Yasuo
Y
Monden
Morito
M
D000818:Animals; D001343:Autophagy; D002462:Cell Membrane / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D015925:Cryopreservation; D022781:Hepatocytes / Q000378:metabolism / Q000648:ultrastructure*; D007728:Kupffer Cells / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D016031:Liver Transplantation / Q000473:pathology*; D008297:Male; D046529:Microscopy, Electron, Transmission; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009926:Organ Preservation / Q000009:adverse effects*; D019188:Organ Preservation Solutions; D051381:Rats; D015427:Reperfusion Injury / Q000473:pathology*; D013696:Temperature
D008869:Microtubule-Associated Proteins; D019188:Organ Preservation Solutions