Plasminogen activator activity and plasmin inhibition in nerves

Abstract

Histochemical studies of the distribution of fibrinolytic activity in the vagus and sciatic nerves of rat, guinea pig, and rabbit showed large areas of diffuse lysis related to the fascicles of the nerve. Foci of lysis were also located in the perineurium, in the peripheral epineurium, and particularly in the epineurium between the fascicles of the nerve. The fibrinolytic activity was caused by a plasminogen activator. The activity was highest in the rat, lowest in the rabbit and intermediate in the guinea pig. Plasmin inhibitors were located histochemically by the fibrin slide 'sandwich' technique. In all three species plasmin inhibition was most pronounced in relation to the nerve fascicles, with the highest degree of inhibition in the guinea pig and less in the rat and rabbit. The discrete localization of plasminogen activator and plasmin inhibitor might be of importance in the control of fibrin deposition and tissue repair following nerve injury or in inflammatory demyelinating diseases.