PURPOSE:
Oxygen is indispensable for
survival and aerobic
metabolism in all mammalian
cells. Inadequate
oxygen triggers a multifaceted cellular response negatively impacting important physiological functions which are observed in clinical
diseases such as
stroke,
drowning,
cardiac arrest, hazardous
gas poisoning,
myocardial infarction and
vascular dementia. In this study, we investigated the
neuroprotective effect of a synthetic
delta-
opioid agonist, [D-Ala2, D-Leu5]
enkephalin (
DADLE), and its
role in ischemic neuronal
injury.
METHODS:
This experiment was conducted
in vitro using a primary
culture of
rat cortical
neurons.
Ischemia induction was performed using a hypoxic chamber. To test the degree of neuronal viability, as protected by
delta-
opioid stimulation with
DADLE under
ischemia, we used three independent approaches including a
lactate dehydrogenase assay, MTT assay, and an immunofluorescent
staining assay for viable
cells. In addition, the
gene expressions of
caspase-3 and
heat shock protein 70 were analyzed using
real-time PCR.
RESULTS:
Incubation of the cortical
neurons with
DADLE protected them from
ischemia-induced cytotoxicity, as observed by all three independent viability assays. Also, we found that its
neuroprotective effect might be related with
suppression of the
caspase-3 gene.
CONCLUSION:
The results of this study suggested that
DADLE exhibits a
neuroprotective effect against
ischemia-induced neuronal
cell death.