Background: Intermittent Pringle manoeuvre resul-ted in less blood loss and better preservation of liverfunction when it was applied for fewer than 120 mi-nutes. The mechanism of better preservation of liverfunction under intermittent Pringle manoeuvre atmolecular level remains unclear. Furthermore, theultrastructural features in the liver with chronic di-seases under intermittent Pringle manoeuvre have notbeen studied. The aim of the study is to investigatethe expression of stress genes and ultrastructuralchange of the liver under intermittent Pringle ma-noeuvre.Methods: From July 1995 to February 1998, 131 pa-tients underwent hepatectomy for liver tumours (61patients without Pringle manoeuvre and 70 patientswith intermittent Pringle manoeuvre). Twenty-fivepatients (15 with Pringle manoeuvre and 10 withoutPringle manoeuvre) were included in the study of he-patic stress gene expression during hepatectomy.Twenty-two patients (18 patients with intermittentPringle manoeuvre and four patients without Pringlemanoeuvre) were randomly assigned for electron mi-croscopic examination.Results: For the expression of stress genes, both theheat shock genes (HSP 70A and HSC 70) and acutephase genes (TNF-α and interleukin-6) were detec-ted simultaneously in the patients with or without in-termittent Pringle manoeuvre. The patients under in-termittent Pringle manoeuvre had relatively highermRNA levels of heat shock gene 70 family, which isrelated to intracellular repair and protection. Induc-tion of TNF-α and interleukin-6 genes, which con-tributed to ischaemia-reperfusion injury and posto-perative complication, was not found in the patientsunder intermittent Pringle manoeuvre. Under the e-lectron microscopy, the hepatic ultrastructure waswell maintained under intermittent Pringle manoeu-vre whatever the liver status, even when the accumu-lated ischaemic duration was extended to 120 min.Conclusion: Intermittent Pringle manoeuvre inducedrelatively higher expression of heat shock genes,which are related to intracellular homeostasis, and isconsistent with the well maintenance of liver ultra-structure. Background: Intermittent Pringle manoeuvre resul-ted in less blood loss and better preservation of liver function when it was applied for fewer than 120 mi-nutes. The mechanism of better preservation of liverfunction under intermittent Pringle manoeuvre atmolecular level remains unclear. Furthermore, theultrastructural features in the aim of the study is to investigate the expression of stress genes and ultrastructuralchange of the liver under intermittent Pringle ma-noeuvre. Methods: From July 1995 to February 1998, 131 pa -tients underwent hepatectomy for liver tumors (61 patients without Pringle manoeuvre and 70 patients with intermittent Pringle manoeuvre). Twenty-five patients (15 with Pringle manoeuvre and 10 without Pringles manoeuvre) were included in the study of he- patic stress gene expression during hepatectomy. Twenty- two patients (18 patients with intermittentPringle manoeuvre and four patie nts without Pringlemanoeuvre) were randomly assigned for electron mi-croscopic examination. Results: For the expression of stress genes, both the hepatic shock genes (HSP 70A and HSC 70) and acutephase genes (TNF-α and interleukin-6) were detec-ted simultaneously in the patients with or without in-termittent Pringle manoeuvre. The patients under in-termittent Pringle manoeuvre had relatively higher mRNA levels of heat shock gene 70 family, which isrelated to intracellular repair and protection. Induc-tion of TNF-alpha and interleukin- 6 genes, which con-tributed to ischaemia-reperfusion injury and posto-perative complication, was not found in the patient or intermittent Pringle manoeuvre. Under the e-lectron microscopy, the hepatic ultrastructure waswell maintained intermittent Pringle manoeu-vre whatever the liver status , even when the accumu- lated ischaemic duration was extended to 120 min. Conlusion: Intermittent Pringle manoeuvre inducedrelatively higher expression of heat shock ge nes, which are related to intracellular homeostasis, and isconsistent with the well maintenance of liver ultra-structure.