Effects on survival of shRNA mediated APE/Ref1 gene silencing in rat spiral ganglion cells in oxidative stress / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To investigate the effects of reducing APE/Ref1 expression in the cultures of rat spiral ganglion cells with oxidative damage induced by H(2)O(2).</p><p><b>METHODS</b>Primary cultured rat spiral ganglion cells were infected with small interfering RNA to APE/Ref1 (Ape1siRNA) for 72 h, followed by treating with H(2)O(2) (0, 10, 25, 50, 100 and 300 µmol/L) for 1 h , and then cultured in normal medium for 24 h. Western blot were used to detect the level of APE/Ref1 protein and phosphorylation of histone protein H2AX in the infected cells. The caspase3 activation was tested by spectrophotometric method . The cell viability was determined by MTT and the apoptosis of spiral ganglion cells was determined by terminal-deoxynucleotidyl transferase mediated nick and labeling (TUNEL).</p><p><b>RESULTS</b>Western blot showed that infection with Ape1siRNA resulted in APE/Ref1 reduced expression in the spiral ganglion cells. Exposing spiral ganglion cultures with reduced expression of APE/Ref1 to H(2)O(2) (50, 100, 300 µmol/L) for 1 h resulted in increasing in the phosphorylation of histone protein H2AX. The reduction in APE/Ref1 significantly reduced cell viability in cultures 24 h after 1 h expression to 50-300 µmol/L H(2)O(2). The apoptosis of cells and caspase 3 activity was detected significantly improved.</p><p><b>CONCLUSIONS</b>The induced of APE/Ref1 results in significantly decrease in spiral ganglion cells viability in oxidative stress. The repairing function of APE/Ref1 is necessary for optimal levels of neuronal rat spiral ganglion cells survival.</p>

Effect of lipopolysaccharide on the permeability of blood labyrinth barrier in guinea pigs / 第三军医大学学报

Objective To investigate the change of the permeability of endotoxin-induced blood-labyrinth barrier(BLB) in guinea pigs.Methods Endotoxin was injected into each tympanic cavity of 27 guinea pigs via superior bulla and Evans blue(EB) was injected via jugular vein before sacrification.Another 27 guinea pigs were served as control by injecting normal saline instead of endotoxin.On 12,24,72 h after injection of endotoxin or normal saline,EB content in BLB was detected after the cochlea were immersed in formamide for 24 h and the pathological change of lateral wall was observed by light microscope and transmission electron microscope.Results The BLB permeability to EB increased in endotoxin-induced cochlea of guinea pigs with prolonged time,and the content of EB was significantly different at 24 h in endotoxin-treated cochlea as compared with that at 12 h and 72 h.No marked morphological changes in the stria vascularis and spiral ligament were observed in control group.The pathologic changes in the lateral wall of cochlea in endotoxin-treated group were inflammatory cell infiltration,blood capillary engorgement,intercellular conjunction cleft.Conclusion The BLB permeability can be increased by endotoxin in the cochlea of guinea pigs,which is mainly caused by the capillary interendothelial cleft and continuous break of endothelial cells in stria vascularis.