Heat stress modulates and protects hepatocyte membrane proteins during sepsis

• Published in: The Journal of surgical research 2004-10, Vol.121 (2), p.334-335
• Main Authors: Przkora, R., Jeschke, M., Haslbeck, M., Heyde, C., Ertel, W., Herndon, D., Bolder, U.
• Format: Article
• Language: English
• ISSN: 0022-4804; 1095-8673
• DOI: 10.1016/j.jss.2004.07.218

Introduction. Hepatic failure is one of the important features of septic multiorgan dysfunction. Previous studies have shown that, in septic rats, heat stress (HS) has a protective effect on bile acid transporters in hepatocyte membranes. This study investigates the influence of HS on hepatocyte membrane proteins, including the transporters oatp and mrp2, during endotoxemia. Methods. Endotoxemia in rats was induced by intraperitoneal injection of Escherichia coli Lipopolysaccharide (LPS), while control rats received saline. Half of each group was exposed to HS, 2 h prior to LPS or saline injection, by external warming to 42°C for 10 min and half of each group was exposed to ambient temperature 2 h prior to LPS or saline injection. Membrane fractions were extracted 0, 6,12, 24, 36, 72, and 108 h after LPS or saline treatment. Extracted proteins were separated using 2D gel electrophoresis. The most dominant spots were analyzed by MALDI-TOF. Transporter proteins, oatp and mrp2, were investigated by Western and Northern blot analysis. Results. The majority of the spots developed 24 h after injection. Membrane proteins, Wnt 13, ribosomal protein L14, VLCAD, BHMT, and HIT-40, were found only in HS-LPS. Protein profiles of the groups receiving either HS, LPS, or HS-LPS returned to normal after 72 h. Western blot analysis of oatp and mrp2 showed a down regulation only in the LPS group. Additionally, mRNA of oatp and mrp2 were prolonged down regulated only in the LPS group. Conclusion. We propose that, during endotoxemia, HS is an important stimulus in modulating and protecting the hepatic membrane proteins, which are involved in metabolism and protein synthesis.