ABSTRACT
Object To determine the timing of NO expression in brain tissue after severely diffused brain injury．It would contribute to the understanding of the pathological and physiological functions of NO．Methods On the basis of the Marmarou diffused brain injury model，the rat was killed at different hours afterward．and the NO expression in brain was measured by Griess reaction．Results It was shown that NO in brain tissue increased quickly after trauma （5.20umol／100g），then decreased in 12h（1.96umol／100g）after trauma，a secondary NO elevation appeared in 24h（2.31umol／100g） and 48h（2.69umol／100g） after DBI．Conclusion It indicated that NO expression in brain tissue increased after trauma．As MCAO ischemia model，there was also NO increase at the intermediate and late stage，which might take part in the secondary pathological changes at late stage of cerebral injury．