Role of HIF-1αin reduction of apoptosis in cortical neurons of rats by sevoflurane preconditioning:the relationship with Slit2∕Robo signaling pathway / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of hypoxia inducible factor?1α ( HIF?1α) in reduction of apoptosis in cortical neurons of rats by sevoflurane preconditioning and the relationship with Slit2∕Robo signaling pathway. Methods Primary cortical neurons obtained from neonatal Sprague?Dawley rats were seeded in 6?well (2 ml∕well) or 96?well plates (100 μl∕well) at a density of 1×106∕ml, and randomly divided into 4 groups ( n=24 each ) using a random number table control group ( C group ) , anoxia?reoxygenation ( A∕R ) group, sevoflurane preconditioning group ( SP group ) and HIF?1α inhibitor 2?methoxyestradiol group ( H group ) . The neurons were subjected to O2?glucose deprivation for 90 min followed by restoration of O2?glucose supply for 24 h. In group SP, the neurons were exposed to 2%sevoflurane for 2 h followed by 5 min washout with phosphate buffered saline for 3 times, and then sevoflurane preconditioning was performed immediately. In group H, sevoflurane preconditioning was performed with 5μmol∕L 2?methoxyestradiol at 72 h of incubation. The apoptosis in neurons was assessed using AnnexinⅤ?FITC∕PI assay, and apoptosis rate ( AR) was calculated. The amount of lactic dehydrogenase ( LDH) released was measured using colorimetric method. The expression of Slit2, Robo1 and Robo4 mRNA and protein was detected by fluorescent quantitative real?time polymerase chain reaction or Western blot. Results Compared with group C, the amount of LDH released and AR were significantly increased, Silt2 and Robo1 mRNA and protein expression was up?regulated, and no significant change was found in Robo4 mRNA and protein expression in A∕R group. Compared with group A∕R, the amount of LDH released and AR were significantly decreased in SP and H groups, and Silt2 and Robo1 mRNA and protein expression was up?regulated, and no significant change was found in Robo4 mRNA and protein expression in SP group. Compared with group SP, the amount of LDH released and AR were significantly increased, and Silt2 and Robo1 mRNA and protein expression was down?regulated in H group. Conclusion HIF?1α mediates reduction of apoptosis in cortical neurons of rats by sevoflurane preconditioning, and the mechanism is associated with Slit2∕Robo1 signaling pathway, but not with Slit2∕Robo4 signaling pathway.