Protective effects of hyperbaric oxygen in secondary spinal cord injury

Objective To investigate the mechanism underlying the protective effect of hyperbaric oxygen (HBO) in secondary spinal cord injury (SCI). Methods Models of acute SCI were established in 96 SpragueDawley rats using Allen's dropping weight technique. The rats were then divided into a HBO group, a high pressure nitrogen normal oxygen group, a normal pressure oxygen group and a normal pressure air group. The injured spinal cords were sampled for morphological studies at the 1 st, 3rd, 7th and 14th day after injury. Apoptotic cells were labeled using the TUNEL technique, and the expression of caspase-3 was detected. The neurological functionality of the spinal cord was assessed by open field locomotor evaluation ( the BBB score). Results The expression of caspase3 in the HBO group decreased significantly more than in the other groups after injury. The number of TUNEL-positive cells was significantly lower in the HBO group as well. Neurological function improved significantly after HBO therapy. Conclusions HBO can down-regulate the expression of caspase-3 and inhibit cell apoptosis in rats after SCI.The protective effect of HBO was related with the oxygen level. Key words: Hyperbaric oxygen;  Spinal cord injury;  Apoptosis