Amelioration of rCBF and PbtO2 following TBI at high altitude by hyperbaric oxygen pre-conditioning

Abstract

Objectives: Hypobaric hypoxia at high altitude can lead to brain damage and pre-conditioning with hyperbaric oxygen (HBO) can reduce ischemic/hypoxic brain injury. This study investigates the effects of high altitude on traumatic brain injury (TBI) and examines the neuroprotection provided by HBO pre-conditioning against TBI.Methods: Rats were randomly divided into four groups: HBO pre-conditioning group (HBOP, n = 10), high altitude group (HA, n = 10), plain control group (PC, n = 10) and plain sham operation group (sham, n = 10). All groups were subjected to head trauma by weight drop device except for the sham group. Rats from each group were examined for neurological function, regional cerebral blood flow (rCBF) and brain tissue oxygen pressure (PbtO2) and were killed for analysis by transmission electron microscope.Results: The score of neurological deficits in the HA group was highest, followed by the HBOP group and the PC group, respectively. Both rCBF and PbtO2 were the lowest in the HA group. Brain morphology and structure seen via the transmission electron microscope was diminished in the HA group, while fewer pathological injuries occurred in the HBOP and PC groups.Conclusions: High altitude aggravates TBI significantly and HBO pre-conditioning can attenuate TBI in rats at high altitude by improvement of rCBF and PbtO2. Pre-treatment with HBO might be beneficial for people traveling to high altitude locations.