EXPERIMENTAL INTRACEREBRAL HEMORRHAGE - DESCRIPTION OF A DOUBLE INJECTION MODEL IN RATS

For experimental purposes, the most common technique of producing an i ntracerebral hematoma in rats is the injection of unclotted autologous blood. All modifications of this model share the problem that size an d extension of the hematoma are not reproducible, because the injected blood either ruptures into the ventricular system or it extends to th e subarachnoid or subdural space. Therefore a double injection model o f experimental intracerebral hemorrhage in rats has been developed usi ng 19 male Sprague-Dawley rats. After inducing anesthesia a cannula wa s stereotactically placed into the caudate nucleus and an intracerebra l hematoma was produced with the double injection method in which firs t a small amount of fresh autologous blood is injected which is allowe d to clot (preclotting) in order to block the way back along the needl e track; the actual hematoma is produced in a second step of the injec tion. The clot volume was measured on stained serial sections. A total injection volume of 50 mu l of autologous blood produced intracerebra l hematomas of 41.1 +/- 10.0 mu l and of similar shapes. The double in jection method allows to generate reproducible hematomas in rats. This new model of intracerebral hemorrhage will allow further investigatio n of fibrinolytic and cytoprotective therapies.