The Effect of Gender on Acute Hydrocephalus after Experimental Subarachnoid Hemorrhage

Acute hydrocephalus is a common complication of subarachnoid hemorrhage (SAH). We investigated the effect of gender on acute hydrocephalus development in a rat SAH model. SAH was induced in adult male and female Sprague-Dawley rats using endovascular perforation. Sham rats underwent the same procedure without perforation. Magnetic resonance imaging (MRI) was performed 24 h after SAH to determine ventricular volume. Hydrocephalus was defined as a ventricular volume that was more than 3 standard deviations from the mean value in sham-operated animals. After MRI, animals were euthanized and the extent of SAH was assessed using a modified grading system. No sham animals died. Mortality rates after SAH induction in male and female animals were 27 and 22 %, respectively. SAH induced significant ventricular enlargement compared with sham-operated rats (p < 0.01). The T2* hypointensity volume in the ventricle (used to assess intraventricular blood) was correlated with ventricular volume after SAH (r = 0.33, p < 0.05). The incidence of acute hydrocephalus 24 h after SAH was greater in female (75 %) than in male animals (47 %, p < 0.05) and the relative changes in ventricular volume were significantly larger in female than in male rats (292 ± 150 % vs 216 ± 127 % of sham-operated animals, respectively, p < 0.05). The increased hydrocephalus occurred even though SAH severity grade and ventricular T2* hypointensity volumes were not significantly different between male and female animals. Our data demonstrate that gender influences acute hydrocephalus development in a rat SAH model. Future studies should determine the role of estrogen in SAH-induced hydrocephalus.