Ethyl docosahexaenoate-associated decrease in fetal brain lipid peroxide production is mediated by activation of...

Area of Science:

• Neuroscience
• Biochemistry
• Pharmacology

Background:

• Intraamniotic administration of ethyl docosahexaenoate (Et-DHA) previously demonstrated reduced fetal brain lipid peroxidation.
• The underlying mechanisms for this protective effect require further investigation.

Purpose of the Study:

• To elucidate the mechanisms by which Et-DHA decreases lipid peroxidation in the fetal brain.
• To investigate the roles of cyclooxygenase (COX) and nitric oxide synthase (NOS) pathways in mediating Et-DHA's effects.

Main Methods:

• Utilized brain slice preparations from Et-DHA treated and control rats.
• Administered various pharmacological agents, including COX and NOS inhibitors, and measured product formation (prostanoids, thiobarbituric acid reactive substances [TBARS], nitric oxide [NO]).

Main Results:

• Et-DHA treated brains showed a 2-3 fold increase in prostanoid (PN) formation, indicating COX activation.
• Indomethacin (a COX inhibitor) blocked PN formation and the Et-DHA-induced decrease in TBARS.
• Phospholipase A2 inhibitors reduced TBARS production in both control and Et-DHA treated brains.
• Et-DHA treated brains released 2.2-fold more nitric oxide (NO), an effect abolished by NOS inhibitors.
• Increasing NO concentration with a donor decreased TBARS levels.

Conclusions:

• Et-DHA's reduction of lipid peroxidation involves activation of COX and NOS pathways.
• These enzymatic pathways likely mediate a shift in oxygen species utilization, contributing to decreased lipid peroxidation.
• The findings suggest a metabolically controlled mechanism for Et-DHA's neuroprotective effects.