Abstract:
Objective To investigate the correlation of heme oxygenase1 (HO-1) expression and autophagy in mice with liver ischemia reperfusion (IR) injury, and to study the influence of HO-1 on the hepatic function. Methods Control group, IR group, Hemin+IR group and Znpp+IR group were constructed. Mice in the Hemin+IR group and the Znpp+IR group were pretreated by Hemin (HO-1 inducer) and Znpp (HO-1 inhibitor) before IR. According to different reperfusion time, the IR group was divided into the 0, 2, 6, 12, 24, 48 and72 hours groups, and the Hemin+IR group and the Znpp+IR group were divided into the 0, 2, 6, 12, 24 hours groups. The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were detected to evaluate the hepatic function. The autophagosome and pathological changes of liver were observed under electron microscope and hematoxylin and eosin (HE) staining, respectively. The expressions of HO-1 and autophagy associated protein (LC3II) in the protein level were detected by Western blot. All data were analyzed using the analysis of variance, t test and q test, respectively. Results The levels of ALT and AST of the IR group, Hemin+IR group and Znpp+IR group were significantly higher than those of the control group (F=96.17, 85.53, P<0.05). The levels of ALT and AST of the IR 12 hours group and 24 hours group were significantly higher than those of the Hemin+IR 12 hours group and 24 hours group (qALT=-14.46,-7.85; qAST=-12.98,-5.26, P<0.05), but significantly lower than those of the Znpp+IR 12 hours group and 24 hours group (qALT=4.25, 4.94; qAST=4.98, 3.53, P<0.05). The results of HE staining showed that hepatic IR injury was significalty alleviated in the Hemin+IR group when compared with the IR group and the Znpp+IR group. The Suzuki degrees of hepatic IR injury in the control group, IR 12 hours group, Hemin+IR 12 hours group and the Znpp+IR 12 hours group were 0.5±0.3, 2.6±0.5, 1.1±0.3, 3.0±0.4, respectively, with significant differences among the 4 groups (F=53.62, P<0.05). There were significant difference in the Suzuki degrees of hepatic IR injury between the IR 12 hours group and the Hemin+IR 12 hours group, and between the IR 12 hours group and the Znpp+IR 12 hours group (q=10.67,14.02, P<0.05). The results of electron microscopy showed that the number of auto phagosome in the IR group was greater than the control group and Znpp+IR group, but lesser than the Hemin+IR group. The numbers of autophagosome in every 10 high power fields of the control group, IR 12 hours group, Hemin+IR12 hours group and the Znpp+IR 12 hours group were 0.4±0.2, 1.8±0.6, 4.0±1.8, 0.7±0.5, respectively, with significant difference among the 4 groups (F=21.35, P<0.05). There were significant differences in the number of autophagosome between the IR 12 hours group and the Hemin+IR 12 hours group, and between the IR 12 hours group and the Znpp+IR 12 hours group (q=6.05,-3.03, P<0.05). The expressions of HO-1 and LC3II in the IR group and the Hemin+IR group were significantly increased. The relative expressions of HO-1 protein in the Hemin+IR 6 hours group and the 12 hours group were 0.64±0.17 and 0.51±0.12,which were significantly higher than 0.45±0.08 and 0.17±0.03 of the IR 6 hours group and 12 hours group (t=4.03, 4.69, P<0.05).The relative expressions of LC3II protein in the Hemin+IR 6 hours group and the 12 hours group were 1.04±0.20 and 1.20±0.23, which were significantly higher than 0.58±0.04 and 0.95±0.14 of the IR 6 hours group and 12 hours group (t=4.29, 6.69, P<0.05). The relative expressions of HO-1 protein in the Znpp+IR 6 hours group and 12 hours group were 0.23±0.03, 0.14±0.02, respectively, and the relative expressions of LC3II protein were 0.35±0.04 and 0.49±0.14, which were significantly lower than the HO-1 and LC3II protein expressions in the IR 6 hours group and 12 hours group (tHO-1=13.82, 7.04; tLC3II=7.21, 4.03, P<0.05). Conclusion HO-1 is positively related to the amelioration of hepatic function, and it may be achieved by induction of autophagy.
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