OBJECTIVETo investigate the effect of hyperbaric oxygen (HBO) treatment on the expression of nitric oxide synthase (NOS) mRNA in cortex after acute traumatic cerebral injury, and to study the mechanism of HBO on brain injury.

METHODSAcute traumatic brain injury model was established with rest received free fall injury method in SD rats. 0.25 MPa HBO treatment was used 1 h or 12 h after brain injury and the cortex was isolated 6 h or 24 h after brain injury respectively. The expression of mRNA coding for nNOS, eNOS or iNOS were assayed using reverse transcription polymerase chain reaction (RT-PCR).

RESULTSThe expression of nNOS, eNOS and iNOS mRNA were significantly decreased in 0.25 MPa HBO treatment groups than those in acute cerebral injury groups (P < 0.01). The amount of nNOS, eNOS and iNOS mRNA was significantly lower in HBOT 24 h group than those in HBOT 6 h group (P < 0.05, P < 0.01). There was no significantly difference among nNOS, eNOS and iNOS mRNA in 0.25 MPa normoxic hyperbaric nitrogen groups and acute cerebral injury groups (P > 0.05).

CONCLUSIONHBO may exert significant effects on the expression of nNOS mRNA/iNOS mRNA and protect cortical neuronal from traumatic cerebral injury.