Vascular and parenchymal lesions along with enhanced neurogenesis characterize the brain of asymptomatic stroke-prone spontaneous hypertensive rats

Lidia Cova, Paolo Gelosa, Elena Mura, Alessandro Mauro, Marco Stramba-Badiale, Georgios Michailidis, Alessandra Colonna, Nadia El Assawy, Alice Pignieri, Giuseppe Busca, Elena Tremoli, Vincenzo Silani, Luigi Sironi, Alberto Zanchetti

Research output: Contribution to journalArticle

Abstract

BACKGROUND AND OBJECTIVES: Spontaneously hypertensive stroke-prone rats (SHRSPs) develop hypertension, cerebrovascular abnormalities and a stroke phenotype in association with higher levels of proteinuria. Here, we focus on cerebral abnormalities preceding lesions detectable by MRI. METHODS: Longitudinal assessment of brain histology was performed in salt-loaded male SHRSPs (na=26) and Wistar-Kyoto (WKY) normotensive control animals (na=27). Groups of rats were sacrificed at different time points: Time 0, before the salt diet administration; Time 1, when proteinuria achieved 40mg/day; Time 2, when proteinuria exceeded 100mg/day. RESULTS: At Time 0, no brain lesions were observed. At Time 1, changes of the cortical penetrating arteries, vasogenic oedema, lacunae and focal cell loss appeared in SHRSPs and worsened at Time 2, although no lesions were yet detected by MRI. Staining for proliferation markers revealed a significant boost of cellular mitosis in the subventricular zone (SVZ) of SHRSPs. Moreover, we observed higher immunopositivity for nestin, glial fibrillary acidic protein and doublecortin (markers for neural stem cells, astrocytes and immature neurons, respectively). At Time 2, apoptotic caspase-3 as well as 4-hydroxynonenal-positive neurons were associated to decreased nestin and doublecortin staining. High expression levels of glial fibrillary acidic protein were maintained in the SVZ. No comparative alterations and SVZ activation were recorded in WKYs. CONCLUSION: Appearance of vascular changes in SHRSPs, before any MRI-detectable brain lesion, is coupled to active neural proliferation in the SVZ. With disease progression, only newborn astrocytes can survive, likely because of the neurotoxicity triggered by brain oedema and oxidative stress.

Original languageEnglish
Pages (from-to)1618-1628
Number of pages11
JournalJournal of Hypertension
Volume31
Issue number8
DOIs
Publication statusPublished - Aug 2013

Keywords

  • apoptosis
  • astrocytes
  • cerebral small vessel disease
  • high-salt diet
  • neural stem cells
  • stroke-prone spontaneous hypertensive rat

ASJC Scopus subject areas

  • Internal Medicine
  • Physiology
  • Cardiology and Cardiovascular Medicine

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