[Alteration of thromboxane A2/prostacyclin and their effect on spinal cord blood flow in experimental spinal cord injury in rats].

In order to document the contribution of Thromboxane (TXA2) and Prostacyclin (PGI2) to the secondary damage following spinal cord injury (SCI) and their effects on spinal cord blood flow (SCBF), the alteration of SCBF, TXB2 and 6-keto-PGF1 alpha concentration in injury site (T13-L1) and adjacent cords (upper: T12, under: L2) were studied using a rat SCI model induced by Allen's weight drop method (50g-cm). The result showed that after SCI the SCBF in injury site significantly reduced during 1-2 hrs and reduced further during 4-8 hrs. The SCBF in adjacent cords also decreased during 4-8 hrs. TXB2 levels significantly increased at 1 hr and reached peak value at 4 hrs. The 6-keto-PGF1 alpha concentration also significantly increased at 1 hr and maintained that level for 24 hrs. The TXB2/6-keto-PGF1 alpha ratio was significantly elevated at 1 hr and reached its peak at 4 hrs after SCI, then gradually decreased to the preinjury level during 8-24 hrs. The negative correlation of SCBF with TXB2 concentration and TXB2/6-keto-PGF1 alpha ratio were appeared. The experimental results indicated that the imbalance of TXB2/6-keto-PGF1 alpha could be the main cause of microcirculatory disturbance and secondary damage in SCI.