STUDY ON THE DAMAGE OF CULTURED HIPPOCAMPAL NEURONS INDUCED BY SEIZURE-LIKE DISCHARGE AND THE EFFECT OF BRAIN-DERIVED NEUROTROPHIC FACTOR ON THE INJURED NEURONS

Abstract

OBJECTIVE: The objective of this study was to observe the damage of cultured hippocampal neurons induced by seizure-like discharge and study the effects of brain-derived neurotrophic factor (BDNF) on such injury. METHODS: Primary cultured hippocampal neurons were randomly divided into 3 groups: (1) control group: cultured neurons were exposed to regular extracellular solution for 3 hours, then returned to regular medium; (2) seizure-like discharge group: cultured neurons were exposed to magnesium-free extracellular solution for 3 hours, then maintained for 24 hours in regular medium; and (3) BDNF-treated group: cultured neurons were precultured with regular medium added to BDNF (200 ng/mL) for 24 hours and exposed to magnesium-free extracellular solution for 3 hours, then maintained for 24 hours in regular medium that contained BDNF. The morphologic changes of neurons dyed by acridine orange/ethidium bromide were observed. Mitochondria membrane potential (MEP) by JC-1 dye was assessed with laser scanning confocal microscope. Lactic acid dehydrogenase (LDH) in supernatant was detected by autobiochemical analyzer. BDNF was detected by immunocytochemistry and assessed by optical density. RESULTS: There were some apoptotic and necrotic neurons in the seizure-like discharge group. Compared with the control group, MEP was significantly decreased and LDH level and BDNF expression were significantly increased in the seizure-like discharge group. Compared with the seizure-like discharge group, MEP was significantly increased and LDH level was significantly decreased in BDNF-treated group, but there was no significant difference on BDNF expression between them. CONCLUSIONS: Seizure-like discharge could induce injury to hippocampal neurons and could upregulate BDNF expression in hippocampal neurons. BDNF could relieve the damage of neurons induced by seizure-like discharge, so BDNF has protective effects on hippocampal neurons.