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Objective:To evaluate the effects of the alpha-lipoic acid on hepatic ischemia/reperfusion (I/R) injury and the role of (ALDH2).Methods:This experiment was performed in two parts in vivo and in vitro experiments. In vivo experiment Twenty-four male Sprague-Dawley rats, aged 8-10 weeks, weighing 250-300 g, were divided into 4 groups ( n=6 each) by the random number table method: sham operation group (Sham group), hepatic I/R group (IR group), and hepatic I/R plus α-lipoic acid group (IR+ ALA group) and hepatic I/R+ α-lipoic acid+ daidzin group (IR+ ALA+ D group). Hepatic I/R was induced by occlusion of the left and middle hepatic lobes for 60 min, followed by 6 h of reperfusion in anesthetized rats.In IR+ ALA+ D group, ALDH2 inhibitor daidzin 50 mg/kg was intraperitoneally injected at 45 min before ischemia.Alpha-lipoic acid 100 mg/kg was intraperitoneally injected at 30 min before ischemia in IR+ ALA group and IR+ ALA+ D group.Blood samples from the inferior vena cava were collected at the end of reperfusion to determine serum AST and ALT activities.Then the rats were sacrificed, and livers were removed for microscopic examination of pathological changes of the lung tissues which were scored and for determination of ALDH2 activity, level of reactive oxygen species (ROS) and expression of 4-hydroxy-trans-2-nonenal (4-HNE) and malondialdehyde (MDA) (by immuno-histochemistry). In vitro experiment Rat BRL-3A hepatocytes cultured in vitro were divided into 4 groups ( n=15 each) by the random number table method: control group (C group), hypoxia-reoxygenation group (HR group), hypoxia-reoxygenation+ α-lipoic acid group (HR+ ALA group) and hypoxia-reoxygenation+ α-lipoic acid+ daidzin group (HR+ ALA+ D group). BRL-3A hepatocytes were exposed to 95% N 2-5% CO 2 in an incubator at 37 ℃ for 6 h followed by reoxygenation with 95% O 2-5% CO 2 for 24 h. At 60 min before hypoxia, alpha-lipoic acid 100 μmol/L was addded in HR+ ALA group, and alpha-lipoic acid 100 μmol/L and daidzin 60 μmol/L were added in HR+ ALA+ D group.At 24 h of reoxygenation, cell viability was measured by CCK-8 method, ALDH2 activity was determined by spectrophotometry, ROS level was detected by DCFH-DA fluorescent probe method, and mitochondrial membrane potential (MMP) was measured by JC-1 method. Results:In vivo experiment Compared with Sham group, the serum AST and ALT activities, liver injury score, level of ROS in liver tissues and expression of 4-HNE and MDA were significantly increased ( P<0.05), and no significant change was found in ALDH2 activity in IR group ( P>0.05). Compared with IR group, the serum AST and ALT activities, liver injury score, level of ROS in liver tissues and expression of 4-HNE and MDA were significantly decreased, and the ALDH2 activity was increased in IR+ ALA group ( P<0.05). Compared with IR+ ALA group, the serum AST and ALT activities, liver injury score, level of ROS in liver tissues and expression of 4-HNE and MDA were significantly increased, and the ALDH2 activity was decreased in HR+ ALA+ D group ( P<0.05). In vitro experiment Compared with C group, the cell viability and MMP were significantly decreased, and the level of ROS was increased ( P<0.05), and no significant change was found in the activity of ALDH2 in HR group ( P>0.05). Compared with HR group, the cell viability, ALDH2 activity and MMP were significantly increased, and the level of ROS was decreased in HR+ ALA group ( P<0.05). Compared with HR+ ALA group, the cell viability, ALDH2 activity and MMP were significantly decreased, and the level of ROS was increased in HR+ ALA+ D group ( P<0.05). Conclusions:Alpha-lipoic acid can reduce hepatic I/R injury in rats, and the mechanism is related to activation of ALDH2, reduction of accumulation of toxic aldehyde and restoration of MMP.
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Objective To investigate the association between matrix metalloproteinase 9(MMP 9) and type 2 diabetic macroangiopathy and explain the mechanism of Simvastatin protective effects on blood vessel.Methods The serum MMP 9 was determined by ELISA in 40 healthy controls and 80 type 2 diabetes(including 40 type 2 diabetic macroangiopathy and 40 type 2 diabetes without complications) before and after Simvastatin treatment.Results The serum MMP 9 in type 2 diabetic macroangiopathy was higher than that in type 2 diabetes without complications and healthy controls.Serum MMP 9 was correlated positively with TC,LDL C,Ox LDL and blood pressure and correlated negatively with HDL C. After Simvastatin treatment,the levels of serum MMP 9 were reduced and serum TC,LDL C and Ox LDL were also decreased.Conclusion MMP 9 may play an important role in the development and progression of type 2 diabetic macroangiopathy.The protective effects of Simvastatin on blood vessel partly attribute to its lowering of serum MMP 9.