Hydrocephalus in a rat model of intraventricular hemorrhage.

The aims of the current study were 1) to establish an adult rat model of intraventricular hemorrhage (IVH) and post-hemorrhagic ventricular dilatation, and 2) to examine the role of alterations in cerebrospinal fluid (CSF) drainage and parenchymal injury in that dilatation. Rats underwent infusion of 200 microl of autologous blood over 15 minutes. The rats were used to measure hematoma mass, ventricular dilatation, and cortical mantle volume (with T2 imaging), resistance to CSF absorption, and brain edema (as a marker of brain injury). IVH resulted in ventricular dilatation peaking at day 2 but persisting for at least 8 weeks. Although there was an increased resistance to CSF absorption at 3 days, it returned to normal at day 7. Long-term ventricular dilatation was not associated with an alteration in cortical mantle volume, although there was evidence of cortical damage (edema). It is possible that initial ventricular distension (due to the hematoma and the impaired CSF drainage) in combination with periventricular white matter damage results in structural changes that prevent total recoil once the hematoma has resolved and CSF drainage is normalized, leading to long-term hydrocephalus.