Background Hypothermia is an established treatment for perinatal asphyxia. Post treatment hypothermia MRI supplemented with H±-MRS is used in clinics as the best predictor for neurodevelopmental outcome. DHA is an omega-3 fatty acid thought to modify apoptosis, inflammation and reduce lipid peroxidation in face of hypoxia. We have previously shown neuroprotective effects of DHA. The current study combines DHA and hypothermia.
Methods 54 newborn pigs (age 12–36 h) were randomised to undergo hypoxia (N=48) or not (Control, N=6). Hypoxia was achieved on fully anaesthetised, intubated piglets through FiO2 0.08 until bloodgases reached Base Excess -20 mmol/L or middle arterial blood pressure below 20 mmHg. Piglets were then block randomised to one of four groups: (1) Hypoxia, (2) Hypoxia + Hypothermia, (3) Hypoxia + DHA or (4) Hypoxia +DHA +Hypothermia. Piglets were mechanically ventilated 9,5 h post end hypoxia and then euthanized. Hippocampal brain tissue was immediately snap frozen in liquid nitrogen. H±-MRS measuring lactate (Lac) and glutamate (Glu) in relation to n-acetylaspartate (NAA) was conducted on frozen tissue. Piglets with autolysis of the brain and outliers over 2 standard deviations were removed from the analysis.
ResultsThe only Lac/NAA ratio significantly different than control, is the hypoxia group (p = 0.016). Intervention groups show no significant changes vs controls. Group 1 vs group 3 shows a borderline significance (p = 0.073).
Conclusion Hypoxia significantly increases the Lac/NAA biomarker and intervention groups are at a pre-hypoxic control level. The pattern consists through the Glutamate group. DHA may be beneficial in neuroprotection after asphyxia.