engleski

Increased rearing and brainstem dopamine levels in a rat model of mild neonatal normobaric hypoxia

Prenatal exposure to acute hypoxia can cause developmental disturbances due to hypoxic-ischemic brain injury. Studies on rat models are necessary for a better understanding of the underlying pathological mechanisms of hypoxia and their effects on behavior. The aim of this study was to determine possible behavioral changes (locomotion, learning, anxiety-like, exploratory and social behavior) and analyze brainstem catecholamine levels in a rat non-invasive neonatal hypoxia model, which mimics mild midgestational hypoxic brain injury in humans. 16 experimental Wistar Han rats (8 females, 8 males) were exposed to normobaric hypoxic conditions (8% O2, 92% N2), in a warm (≈ 27°C) normobaric chamber, for 2 hours on the first postnatal day (PND1). At the same time 15 control rats (8 females, 7 males) were kept under normoxic conditions (21% O₂, 78% N₂). From PND33 to PND45 rats underwent the battery of behavioral tests: open field, hole-board, T-maze and social choice. On PND50 rats were sacrificed, and brainstem samples were collected for 3-CAT ELISA. In comparison to the control group, hypoxic rats displayed highly significant increase in the number of rearings in the open field test, which was accompanied by significantly increased levels of dopamine in the brainstem, showed by 3-CAT ELISA. Conclusion: With this experiment we demonstrated that acute hypoxia can induce very subtle changes in behavior which may arise because of the dopamine imbalance. Increased number of rearings can indicate disturbed spatial mapping in the hippocampus, the function of which can be disrupted by increased dopamine stimulation.

non-invasive ; perinatal brain injury ; spatial mapping ; catecholamines

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