Experimental intracerebral hematoma in the rat

Purpose: Current models of intracerebral hematoma are difficult to use for neurotransplantation studies because of high mortality and important variations of morphology, size and location of blood deposits. We propose a modification of the autologous blood infusion technique in rats to reduce these limitations. Methods: The modification consisted in a mechanical microlesion preceding blood infusion. A canula was stereotactically introduced into the striatum of adult rats. Subsequently, a parenchyma lesion was created by a rotating microcatheter coaxially inserted through the canula, followed by slow infusion of 30 μl autologous blood during 5 minutes. Controls included canula insertion only and canula + microlesion. Hematoma volume/morphology were quantified and the animals behaviorally analysed using standardized tests. Results: Surgical mortality was 0/54 rats. One animal died during follow-up. Hematoma volume was constant and significantly higher (15.20 ± 0.60 mm $^3$ ) than control lesions (canula: 0.11 ± 0.01 mm $^3$ ; canula + trauma: 0.51 ± 0.01 mm $^3$ ). Hematoma edges were sharply delineated and the perihematomal region histologically preserved. Rats with hematoma showed initially a reduced spontaneous rotational behaviour. They also showed persisting deficits of forelimb placing ability. Conclusions: The advantages of this model include a systematic control of all steps of hematoma production, high reproducibility of volume, size, and location of blood deposits, preservation of perihematomal brain tissue, and quantifiable neurological deficits.