Kist Alwine, Wakkie Joris, Madu Max, Versteeg Ruth, ten Berge Judith, Nikolic Andrej, Nieuwenhuijs Vincent B, Porte Robert J, Padbury Robert T A, Barritt Greg J
Department of Medical Biochemistry, Flinders Medical Centre and School of Medicine, Flinders University, Adelaide, South Australia, Australia.
J Surg Res. 2012 Aug;176(2):468-75. doi: 10.1016/j.jss.2011.10.033. Epub 2011 Nov 18.
BACKGROUND/AIMS: Rapamycin, which is employed in the management of patients undergoing liver surgery, induces the synthesis of heme oxygenase-1 (HO-1) in some non-liver cell types. The aim was to investigate whether rapamycin can induce HO-1 expression in the liver, and to test the effects of rapamycin on liver function in the early phase of ischemia reperfusion (IR) injury.
Isolated rat hepatocytes and a rat model of segmental hepatic ischemia and reperfusion were employed. Bile flow was measured gravimetrically or by using indocyanine green. mRNA and protein (by quantitative PCR and Western blot, respectively) and blood concentrations of rapamycin, bilirubin, and liver marker enzymes were measured.
In isolated hepatocytes, rapamycin induced a 6-fold increase in HO-1, comparable to that induced by cobalt proporphyrin (CoPP), and a 2-fold increase in peroxiredoxin-1. Pretreatment of rats with rapamycin resulted in a small increase in liver HO-1 expression, a 20% inhibition of the basal rate of bile flow, and a 50% inhibition in the rate of bile flow recovery after ischemia. CoPP increased basal bile flow by 20% and inhibited bile flow recovery by 50%. These effects were associated with small increases in the blood concentrations of bilirubin and liver marker enzymes.
Rapamycin, through HO-1 induction, has the potential to protect the liver against damage in the late phase of IR. The inhibition by rapamycin of bile flow indicates that its actions on liver function in the acute phase of IR injury are complex.
背景/目的：雷帕霉素用于肝手术患者的治疗，可在某些非肝细胞类型中诱导血红素加氧酶-1（HO-1）的合成。本研究旨在探讨雷帕霉素能否诱导肝脏中HO-1的表达，并测试雷帕霉素在缺血再灌注（IR）损伤早期对肝功能的影响。
采用分离的大鼠肝细胞和大鼠节段性肝缺血再灌注模型。通过重量法或使用吲哚菁绿测量胆汁流量。分别通过定量PCR和蛋白质印迹法检测mRNA和蛋白质，并测量雷帕霉素、胆红素和肝脏标志物酶的血药浓度。
在分离的肝细胞中，雷帕霉素可使HO-1增加6倍，与钴卟啉（CoPP）诱导的增加幅度相当，使过氧化物还原酶-1增加2倍。雷帕霉素预处理大鼠可使肝脏HO-1表达略有增加，基础胆汁流量抑制20%，缺血后胆汁流量恢复率抑制50%。CoPP使基础胆汁流量增加20%，并使胆汁流量恢复抑制50%。这些作用与胆红素和肝脏标志物酶血药浓度的小幅增加有关。
雷帕霉素通过诱导HO-1，有可能在IR后期保护肝脏免受损伤。雷帕霉素对胆汁流量的抑制表明其在IR损伤急性期对肝功能的作用较为复杂。
