Dynamic changes of plasma endothelin and nitric oxide levels in gunn rats with hypoxic ischemic encephalopathy and their relations with hyperbaric oxygen treatment

Objective To investigate the dynamic changes of plasma endothelin (ET) and nitric oxi de (NO) levels in gunn rats with hypoxic ischemic encephalopathy (HIE) and their relations with hyperbaric oxygen (HBO) treatment. Methods We measured the brain water content and plasma ET NO levels before, 12 hours and 24 hours after placing in hypoxic glass room by radioimmunoassay and cadmium column reduction spectrophotometry. Results The plasma NO level was markedly elevated at 12 hours and 24 hours after exposure to hypoxic milieu, whereas the plasma ET levels were also significantly increased, all these were significantly correlated with the brain water content. Conclusion These results suggest that during the hypoxic ischemic encephalopathy process, there is excessive production of NO, the mechanism of action of HBO may be associated with inhibition of NO production and elevation of plasma ET. (Shanghai Med J 1999, 22:667 668)