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正

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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） ofpatients 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

inrat brain was progressively increased within 3h after injury （P

<

0.01）

and the ratio betweenTXB

2

and 6-keto-PGF

1α

（T/K value） increased during the early stage after injury

along withthe tissue damage aggravation.After the use of ligustrazini hydrochlorioi

TXB

2

content inbrain decreased sharply accompanied with a drop in T/K value.Moreover

TXB

2

content inCSF 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 theimportant factors in the development of secondary brain injury

and ligustrazini hydrochlorioiproved 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.