title: Pathological observation of brain arteries and spontaneous aneurysms in hypertensive rats.
abstract: OBJECTIVE
  To investigate the role of hypertension in the pathogenesis of cerebral aneurysms in rats.
  
  
  METHODS
  Twenty spontaneous hypertensive rats (SHR) and 10 Wistar-Kyoto rats (WKY) were included in this observational study. Animals were fed with normal diet and drinking water. No experimental modifications were undertaken in either group. They were sacrificed at one year of age, the bifurcations of the circle of Willis were dissected and longitudinal serial sections were prepared for light microscopic and transmission electron microscopic study.
  
  
  RESULTS
  In the SHR group, 2 of the 20 rats formed an aneurysm respectively at the bifurcations of the basilar artery. As revealed by electron microscopy, injury at the bifurcation of the artery first occurred on the steeper side of the intimal pad. Furthermore, loss of endothelial cells, small depressions on the intima, disruptive internal elastic lamina and lymphocytes or red blood cells infiltration were noted at the steeper side of the intimal pad. No significant changes were observed in WKY group.
  
  
  CONCLUSIONS
  Cerebral aneurysms can form spontaneously in SHR without ligation of the common carotid artery and without a diet containing beta-aminoproprionitrile. Long-standing systemic arterial hypertension is one of the etiological factors that contributes to aneurysm formation in SHR rats.
authors.affiliation: Department of Neurosurgery, Beijing Tiantan Hospital, Capital University of Medical Sciences, Beijing 100050, China. zhangd@public.bta.net.cn
authors.forename: Dong
authors.initials: D
authors.lastname: Zhang
authors.forename: Jizong
authors.initials: J
authors.lastname: Zhao
authors.forename: Yilin
authors.initials: Y
authors.lastname: Sun
authors.forename: Shuo
authors.initials: S
authors.lastname: Wang
authors.forename: Wa Hou
authors.initials: WH
authors.lastname: Tai
authors.forename: Douglas D
authors.initials: DD
authors.lastname: Cochrane
authors.forename: Jingsheng
authors.initials: J
authors.lastname: Li
mesh_terms: D000818:Animals; D002536:Cerebral Arteries / Q000473:pathology*; D006973:Hypertension / Q000150:complications*; D002532:Intracranial Aneurysm / Q000209:etiology* / Q000473:pathology; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY