Effect of etomidate post-conditioning on mPTP in rat cortical neurons subjected to oxygen-glucose deprivation and restoration: the relationship with Robo receptors

Abstract

Objective To evaluate the role of etomidate post-conditioning on mitochondrial permeability transition pore (mPTP) in the rat cortical neurons subjected to oxygen-glucose deprivation and restoration (OGD/R) and the relationship with Robo receptors. Methods The cortical neurons obtained from Sprague-Dawley rats (< 24 h after birth) were cultured in vitro and seeded in 6-well plates (2 ml/well). The neurons were divided into 4 groups (n=24 each) using a random number table: control group (group C), OGD/R group, etomidate post-conditioning group (group E), and etomidate post-conditioning + Robo receptor blocker group (group ER). The neurons were subjected to O2-glucose deprivation for 90 min followed by restoration of O2-glucose supply for 24 h. In E and ER groups, etomidate was added to the culture medium with the final concentration of 6 μmol/L immediately after onset of O2-glucose supply.In group ER, Robo blocker RoboN was added to the culture medium with the final concentration of 1 μg/ml at 6 h before O2-glucose deprivation.The neuronal apoptosis was detected using Hoechst/PI double staining, the viability of neurons was measured by MTT assay, and the amount of lactic dehydrogenase (LDH) released was measured using colorimetric method.The mitochondria were extracted, and mitochondrial permeability transition pore (mPTP) opening was detected. Results Compared with group C, the apoptosis rate, amount of LDH released, and mPTP opening were significantly increased, and the cell survival rate was decreased in OGD/R, E and ER groups (P<0.05). Compared with group OGD/R, the apoptosis rate, amount of LDH released, and mPTP opening were significantly decreased, and the cell survival rate was increased in group E, and the apoptosis and amount of LDH released were significantly decreased, and the cell survival rate was increased in group ER (P<0.05). Compared with group E, the apoptosis rate, amount of LDH released, and mPTP opening were significantly increased, and the cell survival rate was decreased in group ER (P<0.05). Conclusion Etomidate post-conditioning mitigates OGD/R-induced damage to the cortical neurons through activating Robo receptors and inhibiting mPTP opening in rats. Key words: Etomidate; Ischemic postconditioning; Cell hypoxia; Oxygen; Cerebral cortex; Neurons; Mitochondrial membrane transport proteins; Nerve tissue proteins; Receptors, immunologic