Dual role of polyamines in heart ischemia/reperfusion injury through regulation of mitochondrial permeability transition pore / 生理学报

Polyamines (putrescine, spermidine, and spermine) are essential polycations that play important roles in various physiological and pathophysiological processes in mammalian cells. The study was to investigate their role in cardioprotection against ischemia/reperfusion (I/R) injury and the underlying mechanism. Isolated hearts from male Sprague-Dawley rats were Langendorff-perfused and cardiac I/R was achieved by 30 min of global ischemia followed by 120 min of reperfusion. Different concentrations of polyamines (0.1, 1, 10, and 15 μmol/L of putrescine, spermidine, and spermine), cyclosporin A (0.2 μmol/L), or atractyloside (20 μmol/L) were given 10 min before the onset of reperfusion. The hemodynamics were monitored; the lactate dehydrogenase (LDH) levels in the coronary effluent were measured spectrophotometrically; infarct size was determined by the 2,3,5-triphenyltetrazolium chloride staining method; and mitochondrial permeability transition pore (MPTP) opening was determined spectrophotometrically by the Ca-induced swelling of isolated cardiac mitochondria. The results showed that compared to I/R alone, 0.1 and 1 μmol/L polyamines treatment improved heart function, reduced LDH release, decreased infarct size, and these effects were inhibited by atractyloside (MPTP activator). In isolated mitochondria from normal rats, 0.1 and 1 μmol/L polyamines treatment inhibited MPTP opening. However, 10 and 15 μmol/L polyamines treatment had the opposite effects, and these effects were inhibited by cyclosporin A (MPTP inhibitor). Our findings showed that polyamines may have either protective or damaging effects on hearts suffering from I/R by inhibiting or activating MPTP opening.

Establishment of the Chang liver cell line stably overexpressing human UCP2 gene and its effect on mitochondrial membrane potential and reactive oxygen species / 中华肝脏病杂志

To establish the Chang liver cell line stably overexpressing human uncoupling protein 2 (UCP2) and observe the effect of UCP2 on mitochondrial membrane potential (MMP) and reactive oxygen species (ROS). The Chang liver cell line was transfected with recombinant plasmid containing full-length human UCP2 cDNA (pcDNA3.1-hUCP2) or pcDNA3.1 empty vector. The stable cell line was established by antibiotic screening with Zeocin. UCP2 expression was detected by Western blotting and immunocytochemistry. The UCP2 overexpressing cells were pretreated with genipin at various doses (25, 50 and 100 munol/L). MMP and intracellular ROS were detected by fluorescence spectrophotometry. The total normalized protein content in UCP2 overexpressing cells was 1.6-fold higher than that in unmanipulated normal cells. The fluorescence intensities of Rhodamine123 and DCFH-DA in UCP2 overexpressing Chang liver cells (11.11+/-2.76 and 4.97+/-0.62, respectively) were significantly lower than those in unmanipulated normal cells (15.56+/-2.55, P less than 0.01 and 6.14+/-1.25, P less than 0.05, respectively) and in cells transfected with empty vector (16.11+/-2.93, P less than 0.01 and 6.23+/-1.13, P less than 0.05, respectively). Treatment of UCP2 overexpressing cells with 25, 50 and 100 munol/L genipin caused a dose-dependent increase in fluorescence intensities of Rhodamine123 (14.89+/-2.89, 17.89+/-2.93 and 24.00+/-2.55, respectively, all P less than 0.01) and DCFH-DA (9.16+/-0.78, 10.84+/-1.09 and 11.83+/-1.25, respectively, all P less than 0.01). The Chang liver cell line stably overexpressing UCP2 was established successfully. Using this cell system, UCP2 was found to play a role in mitochondrial function by regulating MMP and ROS.

Protective effects of emodin and astragalus polysaccharides on chronic hepatic injury in rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Chinese medicine plays an important role in hepatoprotective treatment. This study was conducted to investigate the protective effects of emodin and astragalus polysaccharides (APS) in a rat model of chronic hepatic injury.</p><p><b>METHODS</b>Chronic hepatic injury was induced by hypodermic injection of an olive oil solution containing 40% carbon tetrachloride (CCl(4)) twice a week, in addition to a diet of 79.5% maizena, 20% fat, 0.5% cholesterol, and 10% alcohol in the drinking water ad libitum for 12 weeks. Meanwhile, the rats were exposed to different concentrations of emodin (40 mg x kg(-1) x d(-1)), APS (200 mg x kg(-1) x d(-1)), combination drug (emodin 40 mg x kg(-1) x d(-1) combined with APS 200 mg x kg(-1) x d(-1)) and colchicine (0.1 mg x kg(-1) x d(-1)) in parallel by oral gavage (once a day for 12 weeks). At the end of 12 weeks, blood serum and liver tissue were taken. Serum was collected to determine the levels of total bilirubin (TBIL), alanine transaminase (ALT), aspartate transaminose (AST), and albumin (ALB). Liver and spleen indexes were assayed, followed by the measurements of the liver associated enzyme superoxide dismutase (SOD) and malondialdehyde (MDA). Histopathological changes were studied using optical microscopy.</p><p><b>RESULTS</b>Splenohepatomegalia was alleviated and serum levels of TBIL and ALT were reduced in the groups treated with emodin and APS when compared to the control group. In addition, the ALB level in the APS and combination groups was higher. Similarly, the SOD activity of liver homogenates was significantly higher in the groups treated with emodin and APS, while administration of the herbal derivatives prevented the elevation in MDA levels. Histological analysis showed that the APS and combination groups significantly ameliorated the hepatic injury.</p><p><b>CONCLUSIONS</b>Co-administration of emodin and APS demonstrated a synergistic action in reducing ALT and restoring ALB in the serum from a rat model of chronic hepatic injury. Emodin and APS may ameliorate the CCl(4)-induced hepatic injury in rats by elevating antioxidant-enzyme activities and reducing lipid peroxidation.</p>