Added after Anoxia-Reoxigenation Stress, Genistein Rescues from Death the Rat Embryo Cortical Neurons

Estrogens and phytoestrogens have neuroprotective effect against neuronal damage induced by cerebral ischemia /reperfusion (I/R) injury. In preceding studies, the phytoestrogen effects have been assessed by administration previous to the ischemic period, conditions which are unusual to apply to the treatment of human stroke. Here we present a study on neuroprotection afforded by genistein on rat embryo cortical neurons subjected to oxygen and glucose deprivation (OGD) followed by re-oxigenation, when added after the stress stimulus. At 1 and 2 h of OGD times and after 24 h of reperfusion, cell viability, necrotic, apoptotic and autophagic cell death and different parameters related to oxidative stress and mitochondrial dysfunction were measured in the absence and presence of 1 μM genisteine. We found an increasing loss of neuronal viability after 1-5 h of OGD which was only reversed in part by 24 h of reperfusion. These changes were preceded by increases in ROS generation, caspase-3 activation, LDH release and increase in LC3B lipidation, indicative of autophagia. Treatment with 1 μM genistein during the 24 h reperfusion significantly attenuated neuronal necrosis and autophagia induced by 1 and 2 h of OGD exposure. Genistein also decreased ROS generation and lipid-peroxidation induced by 2 h of OGD. These results suggest an important neuroprotective effect of genistein against transient post-ischemic-like conditions.