| Objective: In order to explore the protective effect of remifentanil against hepatic ischemia-reperfusion (I/R) injury and its mechanism, we studied on the protective effect of remifentanil against hepatic ischemia-reperfusion injury with continuous intravenous pumping; Observing and analyzing the feasibility of the protective effect of remifentanil against hepatic ischemia-reperfusion injury; These finding will provide a basis for clinical practice.Methods: Sixty healthy male SD rats weighing 250±20g were divided into 4 groups randomly: group A (blank control group): we just needed to anaesthetize these rats and open abdominal cavity to turn up the lives in order to expose porta hepatic without blocking of hepatofugal portal flow; Group B (ischemia-reperfusion group): we blocked hepatofugal portal flow; Group C (low concentration of remifentanil group): pumping remifentanil via the rats tail vein with continued constant speed (0.2μg/kg/min) from 20 minutes before ischemia to end; Group D (high concentration of remifentanil group): pumping remifentanil via the rats tail vein with continued constant speed (1μg/kg/min) from 20 minutes before ischemia to end. Using the hepatic ischemia law of 70% in real terms in the three groups of B, C, D, that is, using non-invasive artery clamp to block the left and middle hepatic lobes'artery and biliary duct. Removing the folder to restore arterial blood supply of the liver after 30 minutes ischemia and taking the lives after 60 minutes'reperfusion. Then we selected the left hepatic lobes to make into crumb about 1×1×1mm using sharp knife to prepare for using the electron microscope camera to observe hepatic ultra structure, and then cut two small refrigerator freezers for the production of organizational dissolution to detect Ca2+-Mg2+-ATPase,Na+-K+-ATPase activity and SOD,MDA content, fixed the remainder of the liver by 10% formalin and make into paraffin-embedded sections, observed the sample under light microscope camera after HE staining.These four group rats were took blood sample from the carotid artery blood each 1.5ml at 20 minutes before ischemia, 30 minutes of ischemia and 60 minutes after reperfusion to determine ALT and AST.SPSS13.0 statistical software was applied to conduct statistical analysis. Data were expressed as means±std. Comparisons between groups were made by using one-way ANOVA and comparisons in group were made by using repeated measure ANOVA. If the difference between the contrast group was a significant statistical one, express the statistical significance using P<0.05 and P<0.01. Results:1 The results of hepatic function:There is no significant difference about concentrations of serum ALT and AST before ischemia, after ischemia and after reperfusion in group A; There is significantly increased about concentrations of ALT and AST at 30 minutes of ischemia and have a further increasing reperfusion at 60 minutes; The concentrations of serum ALT and AST in group C and D at 30 minutes of ischemia and reperfusion at 60 minutes is increaser in group A, there is a significant difference (P<0.01); The concentrations of serum ALT and AST in group D at 30 minutes of ischemia is lower than the level in the same period in group B, there is a significant difference (P<0.05), but there is no significant difference with the level in the same period in group C; The concentrations of serum ALT and AST in group C and D reperfusion at 60 minutes is lower than the level in the same period in group B, there is a significant difference (P<0.01), the concentrations of serum ALT and AST in group D is lower than the level in group C in this period, there is a significant difference (P<0.01).2 Ca2+-Mg2+-ATP enzyme and Na+-K+-ATP enzyme activity in hepatic tissue:The Ca2+-Mg2+-ATP enzyme and Na+-K+-ATP enzyme activity in group A is higher than other groups, there is a significant difference (P<0.01); And these two enzyme activity in group C and D was higher than group B, there is a significant difference (P<0.01); At the same time the activity of these two enzyme in group D was higher than group C, there is a significant difference (P<0.05).3 SOD content in hepatic tissue:The SOD content in group A was higher than other groups, there is a significant difference (P<0.01); And SOD content in group C and D was higher than group B, there is a significant difference (P<0.05 and P<0.01); At the same time SOD content in group D was higher than group C, there is a significant difference (P<0.01).4 MDA content in hepatic tissue:The MDA content in group A was significantly lower than other groups, there is a significant difference (P<0.01); And MDA content in group C and D was lower than group B, there is a significant difference (P<0.01); At the same time MDA content in group D was lower than group C, there is a significant difference (P<0.01).5 The result of light microscope:In blank control group, the structural of hepatic is integrated, hepatic cells are arranged regularly, no significant variability, no necrosis; With the blank control group comparing to the hepatic tissue, ischemia-reperfusion group with liver cell edema significantly with more space vesicle degeneration, liver sinusoid narrowing, and some have small pieces of liver cell necrosis, the structure of normal liver is disordered; Remifentanil treatment group (C, D group), the lack of above-mentioned pathological changes in this group is lighter than the changes in ischemia-reperfusion group, hepatocellular cloudy swelling, a small number of somewhat necrosis, liver plate structure is basically normal.6 The result of light microscope:In blank control group, mainly in normal cells, nuclear morphology regularity, nuclear membrane is integrated and there are lots of round nuclear, mitochondrial membrane and cristae is normal; Comparing to the blank control group, the nuclear chromatin aggregation and edge set in ischemia-reperfusion group, part of the nuclear membrane rupture, the morphology of nuclear is irregular, mitochondrial swelling obviously, cristae fracture or disappearance; Remifentanil treatment group (C, D group), the lack of above-mentioned pathological changes in this group is lighter than the changes in ischemia-reperfusion group, tends to a normal cell morphology, individual chromatin margination, mitochondrial swelling reduced significantly, and less ridge fracture.Conclusion:1 It plays a role in protection against hepatic ischemia- reperfusion injury, constant low-speed pumping remifentanil in the surgical process in rats.2 The effect of protection is induced partly relevant to hepatic cell calcium overload and oxygen free radical damage.3 The effect of protection strengthens with rate of infusion at a certain range.
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