title: Elastase-induced intracranial dolichoectasia model in mice.
abstract: BACKGROUND
  Intracranial dolichoectasia is associated with high morbidity, and its pathophysiology remains poorly understood.
  
  
  OBJECTIVE
  To develop a technique for the creation of a murine model of dolichoectasia.
  
  
  METHODS
  C57/BL6 mice were injected with 0 milliunit (mu) (control, n = 5), 15 mu (n = 7), 25 mu (n = 10), 35 mu (n = 10), and 55 mu (n = 6) of elastase in the cisterna magna. Fourteen days after injection, the vasculature of the brain was perfused with MicroFil polymerizing compound. Tortuosity index and the percentage increase in arterial diameter were calculated for the basilar artery, posterior communicating arteries, and the A1 segment of the anterior cerebral arteries. Tortuosity index >10 combined with 25% increase in diameter were used to indicate success in achieving dolichoectasia.
  
  
  RESULTS
  The mortality rate was 28%, 30%, 80%, and 83% in the 15, 25, 35, and 55 mu groups, respectively. As the 35 and 55 mu groups experienced unacceptable mortality rates, they were excluded from further analysis. The tortuosity index and percent increase arterial diameter of the 15 and 25 mu groups for the left anterior cerebral arteries, right anterior cerebral arteries, left posterior communicating arteries, right posterior communicating arteries, and basilar artery were significantly higher (TI >10 and arterial diameter >25%) than in the control. There was no significant difference in tortuosity index or artery diameter between the 15 and 25 mu groups for any of the 5 artery segments.
  
  
  CONCLUSIONS
  Elastase injection through the cisterna magna can induce intracranial dolichoectasia in mice. Fifteen to 25 mu of elastase is an appropriate dose to use with acceptable mortality.
authors.affiliation: *Neuroradiology Research Laboratory, and ‡Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota.
authors.forename: Daying
authors.initials: D
authors.lastname: Dai
authors.forename: Ram
authors.initials: R
authors.lastname: Kadirvel
authors.forename: Issa
authors.initials: I
authors.lastname: Rezek
authors.forename: Yong-Hong
authors.initials: YH
authors.lastname: Ding
authors.forename: Ravi
authors.initials: R
authors.lastname: Lingineni
authors.forename: David
authors.initials: D
authors.lastname: Kallmes
mesh_terms: D000818:Animals; D001921:Brain; D004195:Disease Models, Animal; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010196:Pancreatic Elastase / Q000633:toxicity*; D014715:Vertebrobasilar Insufficiency
chemical_list: D010196:Pancreatic Elastase