Hydrocortisone rapidly induces aortic rupture in a genetically susceptible mouse.

The Blotchy mouse has an X-linked trait that leads to aortic aneurysms and subsequent fatal rupture in nearly all affected male mice. Heterozygous female mice occasionally develop aneurysms, but they rarely rupture. Ten heterozygous female mice received 0.45 mg/mL of hydrocortisone acetate in drinking water. Within 2 weeks, 9 of 10 mice were dead (6 with proved aortic rupture, 3 with presumed rupture). The 10th mouse was documented to have an aortic aneurysm. A dose-response curve was generated. Hydrocortisone's effect was shown to be dose-dependent. In another experiment, normal female mice received 0.10 mg/mL of hydrocortisone acetate for 14 days. Two mice developed aneurysms, and the others developed aortic ectasia. These experiments establish the role of hydrocortisone in the induction of aortic rupture in a mouse with genetic susceptibility and the induction of aneurysms and ectasia in normal mice.