Brain TXA(2) and PGI(2) levels related to diffuse brain injury with secondary insults

Secondary insults such as hypotension and hypoxia with head injury are asso ciated with increased mortality and morbidity in comparison with head injur y alone, in the present study the changes of brain thromboxane A(2) (TXA(2) ) and prostacyclin (PGI(2)) levels in a Marmarou's rodent model of diffuse brain injury with hypotension and hypoxia were observed and the effect of d iaspirin cross linked haemoglobin solution (DCLHb) were also investigated. Thirty-two male Sprague-Dawley (SD) rats were randomized into four groups: sham; head injury alone; head injury with secondary insults; and injury wit h insults followed by DCLHb administration. The results showed that there w ere no changes in TXB2 and 6-keto-PFG(1a) (metabolites of TXA(2) and PGI(2) ) levels in the injury alone group, while TXB2 levels in the secondary insu lts group were elevated significantly; both TXB2 and 6-keto-PGF(ta) levels in the injury with insults followed by DCLHb administration group were augm ented significantly in comparison with the corresponding value of sham at 4 postimpact. The only increase in TXA, levels in the secondary insults rats suggests that an imbalance in TXA(2)-PGI(2) production contributes to the traumatic secondary processes, which include ischaemia and oedema. It is hy pothesized that DCLHb may exert its protective properties through increasin g PGI(2) production in injured brain by improving blood supply to injured b lood vessels.