[Effects of hypertonic saline on expression of heme oxygenase enzyme-1 in hepatic ischemia/reperfusion injury rats].

Objective: To explore the effect of the pretreatment with hypertonic saline (HTS) in the hepatic ischemia/reperfusion (I/R) injury.
Methods: Twenty-five SD rats were randomly divided into sham operation group, heme oxygenase-1 (HO-1) blocker ZnPP group, I/R group, HTS pretreatment group and ZnPP intervention group (n=5). The rat model of partial hepatic I/R injury was reproduced by isolating the portal venous and hepatic arterial branches to the left and median hepatic lobes, and they were occluded with a microvascular clamp for 30 minutes, followed by reperfusion. In HTS pretreatment group, the rats received 4 ml/kg volume of HTS (7.5%) intravenous 1 hour before the occlusion of the vessels. The rats were sacrificed 6 hours after reperfusion. The levels of alanine aminotransferase (ALT) and tumor necrosis factor-alpha (TNF-alpha) in serum, liver myeloperoxidase (MPO) activity and liver endothelin-1 (ET-1) were determined. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to examine the expression of HO-1 in the liver. The pathological changes in the liver, including hepatic sinusoid, were evaluated in hematoxylin and eosin (HE)-stained sections and transmission electron microscopy (TEM) of liver specimens. The effect of HTS pretreatment was also assessed in the rats pretreated with ZnPP.
Results: The levels of serum ALT and TNF-alpha, ET-1 and MPO activity in hepatic tissues increased after hepatic I/R injury (all P<0.01), and expression of HO-1 mRNA and protein were also increased. RT-PCR and Western-blot revealed that the expression of HO-1 in the liver was upgraded significantly, and the ALT level, serum TNF-alpha, liver MPO activity and liver ET-1 were suppressed significantly after I/R injury in the HTS pretreatment group. In this group, there were moderate swelling of hepatocytes and mild neutrophils infiltration in the liver. The hepatic microcirculatory dysfunction was ameliorated. All these findings showed that HTS pretreatment produced the effect of prevention on hepatic I/R injury. However, the adjunctive infusion of ZnPP abrogated the beneficial effects.
Conclusion: Pretreatment of HTS has the effect of the prevention of hepatic I/R injury by promotion of the expression of HO-1.