Delayed Effects of Neonatal Administration of Non-Opioid Analog of Leu-Enkephalin on Cerebral Consequences of Antenal Hypoxia

In 60-day-old male rats after antenatal hypoxia, the body weight and the absolute weight of the cerebral hemispheres were significantly lower than in the progeny of intact animals. Analysis of brain sections stained with silver nitrate revealed reduced number of nucleoli in neocortical layer II and hippocampal CA1 neurons and smaller area of neuronal nuclei in neocortical layer V and total area of nucleoli in neurons of all studied zones. The animals demonstrated increased locomotor activity in the elevated plus-maze test. Chemiluminescent analysis of brain homogenates revealed the presence of oxidative stress at the organ level. Neonatal administration of non-opioid analog of leu-enkephalin (peptide NALE) after antenatal hypoxia normalized body weight, neutralized morphometric changes in the nucleoli and nuclei of neurons in the neocortex and hippocampus, and improved oxidative status of the brain. In 30- and 60-day-old male rats subjected to antenatal hypoxia and receiving peptide NALE during the neonatal period, behavioral responses were partially normalized. Non-opioid analog of leu-enkephalin can be a promising drug for correction of cerebral consequences of antenatal hypoxia.