Fibrinolytic activity in experimental intracerebral hematoma.

We investigated the tissue fibrinolytic activity in an experimental model of intracerebral hematoma was developed in the guinea pig. Intracerebral hematoma was created by stereotaxically injecting 0.2 ml autologous blood into the left frontal lobe of a total 63 anesthetized adult male albino guinea pigs (weighing 280-350 gr.). The fibrinolytic activity was studied using conventional histochemical stain techniques. 20 guinea pigs were used for developing the intracerebral hematoma model; in the 43 guinea pigs, the intracerebral hematomas were studied sequentially. Intracerebral hematoma formation failed in 10 of 43 guinea pigs. Three guinea pigs died in the immediate postoperative period. It was diagnosed histopathologically purulent meningitis and ventriculitis in four guinea pigs. Tissue fibrinolytic activity was increased in the meninges and choroid plexus. No fibrinolytic activity was observed a during the first days (1 to 3 days after hematoma production). 3 to 5 days later, fibrinolytic activity was seen in the capillary buds surrounding the hematoma and among the infiltrating mononuclear cells. This activity reached highest levels for 7-14 days following production of the hematoma and decreased after 20 days. In conclusion, tissue fibrinolytic activity associated with neovascularisation and mononuclear cell infiltration appears to be important in lysis of intracerebral hematoma.