Figure 1.

The incidence of intracranial aneurysms, the cumulative incidence of subarachnoid hemorrhage and the rate of rupture of induced lesions. To induce intracranial aneurysms, 10-week-old male (n = 18) or female Sprague−Dawley rats (n = 31) were subjected to the ligation of the left carotid artery, the right external carotid artery and the right pterygopalatine artery, and systemic hypertension by the combination of a high salt diet and the ligation of the left renal artery. In some female rats (n = 14), the bilateral ovariectomy was also applied. Animals were maintained for 120 days after surgical manipulations. The incidence of intracranial aneurysms (a), the cumulative incidence of subarachnoid hemorrhage (SAH) (b), the rate of rupture of induced lesions (c) or systolic blood pressure (sBP) (d) in each group; male rats, female rats without ovariectomy (female) or female rats with the bilateral ovariectomy (ovariectomized), are shown. Bars in (d) indicate the mean ± SEM. Statistical analysis was done by the Tukey-Kramer method in (c,d). * p < 0.05, ** p < 0.01, *** p < 0.001.