Intracellular Ca2+ regulation in hepatocytes under experimental transplantation conditions.
Under transplant conditions excessive accumulation of intracellular calcium ([Ca2+](i)) is considered to be a mediator of cell injury during ischaemia and re-oxygenation. To clarify this consideration as well as the necessity of calcium-free preservation solutions, we used a well-known in-vitro model. Furthermore, a new application to mimic clinical situation was established, and we evaluated the correlation between [Ca2+](i) change and cell survival in monolayers of isolated rat hepatocytes undergoing cold hypoxia in defined solutions and during re-oxygenation. [Ca2+](i) was measured in single cells by ratio imaging of Fura-2 fluorescence after various periods of cold hypoxia (ischaemia phase) in different preservation solutions [UW, HTK, EC and Krebs-Henseleit buffer (KH)] and following warm normoxic reperfusion (re-oxygenation phase) with KH. Cell survival was measured simultaneously by trypan-blue exclusion. Cell survival decreased, depending on preservation solution and preservation time. The partially tremendous [Ca2+](i) change under cold hypoxia did not correlate with the change in cell survival. For example, UW-stored cells showed a [Ca2+](i) loss from 280 nM to 56 nM, compared with KH-stored cells with a [Ca2+](i) increase of up to 445 nM. Our results indicate that [Ca2+](i) plays only a minor role in the pathomechanisms of hypoxic and re-oxygenation hepatocellular injury.
Baumstark
Christina
C
Department of General Surgery, University of Tübingen, Hoppe-Seyler-Strasse 3, Germany.
Schenk
Martin
M
Becker
Horst-Dieter
HD
Sessler
Michael J
MJ
D000818:Animals; D002118:Calcium / Q000502:physiology*; D015687:Cell Hypoxia; D002470:Cell Survival; D002478:Cells, Cultured; D022781:Hepatocytes / Q000166:cytology / Q000502:physiology* / Q000637:transplantation*; D008297:Male; D023421:Models, Animal; D019188:Organ Preservation Solutions; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D019188:Organ Preservation Solutions; D002118:Calcium