An experimental and clinical study on TXA_2 and PGI_2 content after head injury

The correlation of secondary brain injury with thromboxane A_2(TXA_2) and prostacy- clin (PGI_2) levels following head injury was studied in rats and patients.Thromboxane B_2 (TXB_2) and 6-keto-PGF_(1α) in rat brain homogenate and TXB_2 in cerebral spinal fluid (CSF) of patients with severe head injury were determined by RIA.The effects of ligustrazini hydrochlo- rioi were also tested.The results showed that the concentration of TXB_2 and 6-keto-PGF_(1α) in rat brain was progressively increased within 3h after injury (P<0.01),and the ratio between TXB_2 and 6-keto-PGF_(1α)(T/K value) increased during the early stage after injury,along with the tissue damage aggravation.After the use of ligustrazini hydrochlorioi,TXB_2 content in brain decreased sharply accompanied with a drop in T/K value.Moreover,TXB_2 content in CSF increased within 7 d after injury (P<0.01),and it reached its peak value on the 3rd day. This could indicate that the metabolic imbalance between TXA_2 and PGI_2 might be one of the important factors in the development of secondary brain injury,and ligustrazini hydrochlorioi proved to have a protective effect on the brain tissue by normalizing the metabolism of TXA_2 and PGI_2.In addition,the metabolic disorders of TXA_2 in the brain tissue of head injured pa- tients have much to do with the outcome of the patients.