Dose-effect Relationship of Hyperbaric Oxygen Therapy in Rats with Amnestic Mild Cognitive Impairment

Background: Amnestic mild cognitive impairment (aMCI) represents an intermediate stage between normal aging and dementia. Hyperbaric oxygen (HBO) therapy, has shown promise in enhancing brain oxygenation and promoting neural stem cell proliferation. Methods:80 SD male adult rats were randomly divided into control group, amnestic mild cognitive impairment group(aMCI group) and hyperbaric oxygen group(HBO group).The HBO group was divided into 6 subgroups according to different treatment pressures: 1.6ATA subgroup, 1.8ATA subgroup, 2.0ATA subgroup, 2.2ATA subgroup, 2.5ATA subgroup and 2.8ATA subgroup, with 10 in each group. The HBO group received hyperbaric oxygen therapy at the specified pressure for 60 minutes per day for 5 consecutive days. Results:After hyperbaric oxygen treatment, compared with the aMCI group, the escape latency of each HBO subgroup was significantly shortened (p<0.001). The 2.0ATA subgroup (p=0.001), 2.2ATA subgroup (p=0.001)and 2.5ATA subgroup ( p=0.002) significantly increased the number of platform crossings.the levels of SOD were significantly increased in1.6ATA subgroup (p=0.019), 1.8ATA subgroup(p =0.003), 2.0ATA subgroup(p=0.010 ) and 2.2ATA group(p=0.016) and MDA contents were significantly decreased in the 1.6ATA subgroup(p=0.015), 1.8ATA subgroup(p =0.012), 2.0ATA subgroup(p=0.002), and 2.2ATA subgroups (p<0.001), and the levels of eNOS were significantly decreased in the 1.8ATA subgroup(p=0.007) and 2.0ATA subgroup (p=0.029),and the expression of nNOS were significantly decreased in the 1.8ATA subgroup (p=0.006),2.0ATA subgroup (p<0.001) and the 2.2ATA subgroup ( p< 0.001). Conclusions:In aMCI model rats found that HBO treatment at a pressure of 2.0 ATA with a stabilization time of 60 minutes per day for 5 days was the most effective.