Characterization of the expression of inducible nitric oxide synthase in rat and human liver during hemorrhagic shock.
It has been previously shown that the inducible nitric oxide (NO) synthase (iNOS; NOS-2) is elevated after hemorrhage, and that iNOS-derived NO participates in the upregulation of inflammation as well as lung and liver injury postresuscitation from shock. The purpose of this study was to elucidate the time course of iNOS mRNA expression, as well as the cellular and subcellular localization of iNOS protein in the liver posthemorrhage in rats subjected to varying durations of hemorrhagic shock (HS; mean arterial blood pressure [MAP] = 40 mmHg) with or without resuscitation. Expression of iNOS mRNA in rat liver by real-time reverse transcriptase (RT)-PCR demonstrated iNOS upregulation in shocked animals as compared with their sham counterparts as early as 60 min after the initiation of hemorrhage. By 1 h of HS, iNOS protein was detectable in rat liver by immunofluorescence, and this expression increased with time. Immunofluorescence localized iNOS primarily to the hepatocytes, and in particular to hepatocytes in the centrilobular regions. This analysis, confirmed by immunoelectron microscopy, revealed that iNOS colocalizes with catalase, a peroxisomal marker. Furthermore, we determined that iNOS mRNA is detectable by RT-PCR in liver biopsies from human subjects with HS (MAP < 90 mmHg) associated with trauma (n = 18). In contrast, none of the seven nontrauma surgical patients studied had detectable iNOS mRNA in their livers. Collectively, these results suggest that hepatic iNOS expression, associated with peroxisomal localization, is an early molecular response to HS in experimental animals and possibly in human patients with trauma with HS.
Collins
Joy L
JL
Department of Surgery, University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
Vodovotz
Yoram
Y
Hierholzer
Christian
C
Villavicencio
Raphael T
RT
Liu
Shubing
S
Alber
Sean
S
Gallo
David
D
Stolz
Donna B
DB
Watkins
Simon C
SC
Godfrey
Anthony
A
Gooding
William
W
Kelly
Edward
E
Peitzman
Andrew B
AB
Billiar
Timothy R
TR
D000818:Animals; D001706:Biopsy; D002374:Catalase / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D022781:Hepatocytes / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000201:enzymology* / Q000473:pathology; D008297:Male; D018613:Microscopy, Confocal; D016253:Microscopy, Immunoelectron; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D020675:Peroxisomes / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012771:Shock, Hemorrhagic / Q000378:metabolism*; D013997:Time Factors; D015854:Up-Regulation
D012333:RNA, Messenger; D002374:Catalase; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat