Transient neurobehavioral dysfunction secondary to oxygen induced convulsion is not related to cerebral blood flow reduction.

This study aimed to investigate changes in blood flow following hyperbaric oxygen (HBO) exposure and their association with neurobehavioral dysfunction after oxygen-induced convulsions. Eighteen male C57 mice were randomly assigned to an oxygen toxicity (OT) group, a 40-m group, and a 15-m group (n = 6 per group). After the chamber was flushed with pure oxygen, mice were pressurized at a rate of 100 kPa/min. Mice in the OT group were exposed to 100% oxygen at 500 kPa until convulsions occurred; mice in the 40-m group were exposed to 100% oxygen at 500 kPa for 10min without developing convulsions; and mice in the 15-m group were exposed to 100% oxygen at 250 kPa for 30min without developing convulsions. After exposure, mice were decompressed at a rate of 100 kPa/min. Neurobehavioral function was assessed using the Y-maze test before exposure and at different time points after exposure. Cerebral blood flow (CBF) and femoral blood flow (FBF) were also measured, and the associations between changes in blood flow and neurobehavioral alterations were further evaluated. Results showed oxygen-induced convulsions significantly impaired spatial memory, whereas hyperbaric hyperoxia exerted differential effects on spatial memory, locomotor activity, and exploratory activity. These neurobehavioral alterations were transient and largely recovered within several hours after exposure. CBF decreased significantly immediately after HBO exposure, with a more pronounced reduction in mice exposed to 500 kPa, and subsequently recovered toward baseline levels. FBF also decreased after exposure although the changes were less pronounced. No significant association was observed between post-exposure CBF reduction and neurobehavioral dysfunction. In conclusion, oxygen-induced convulsions cause transient spatial memory impairment, whereas neurobehavioral dysfunction following HBO exposure is not directly associated with the reduction in CBF.