Effects of diazoxide pretreatment on the expression of NF-kB mRNA and fractalkine mRNA in rat myocardial microvascular endothelial cells exposed to hypoxia-reoxygenation

Objective To investigate the effects of diazoxide pretreatment on the expression of NF-κB mRNA and fractalkine （FKN） mRNA in rat myocardial microvascular endothelial cells exposed to hypoxia-reoxygenation （H/R）. Methods The SD rat myocardial microvascular endothelial cells were cultured. The cells were seeded in 96-well plates （100μl/hole） or in 6 cm diameter dishes （2 ml/dish） with the density of 1 × 106/ml and randomly divided into4 groups （n = 24 each）： Ⅰ normal control group （group C）, Ⅱ H/R group, Ⅲ diazoxide pretreatment group （group DZ）, Ⅳ diazoxide pretreatment ＋ mitochondrial ATP-sensitive potassium channel blocker 5-hydroxydecanoate （5-HD） group （group DZ ＋ 5-HD）. The cells were exposed to 2 h hypoxia followed by 2 h reoxygenation. Diazoxide 100 μmol/L and diazoxide 100 μmol/L ＋ 5-HD 100μmol/L were added to the cultured medium 2 h before hypoxia in group DZ and DZ ＋ 5-HD respectively. The cell vitality, apoptotic rate and expression of NF-κB mRNA and FKN mRNA were detected at end of reoxygenation. Results Compared with group C, the cell vitality was significantly decreased, apoptotic rate increased and the expression of NF-κB mRNA and FKN mRNA up-regulated in H/R group. Compared with group H/R, the cell vitality was significantly increased,apoptotic rate decreased and the expression of NF-κB mRNA and FKN mRNA down-regulated in group DZ. 5-HD could inhibit diazoxide pretreatment-induced changes mentioned above. Conclusion Diazoxide pretreatment can reduce H/R injury in rat myocardial microvascular endothelial cells through down-regulating the expression of NFκB and FKN, and the mechanism is related to activation of mitochondrial ATP-sensitive potassium channels. Key words: Dazoxide; Heart; Endothelium,vascular; Oxygen; Cell hpoxia; NF-kappa B; Chemokine CX3CL1