1. Aging exacerbates development of cerebral microbleeds in a mouse model
- Author
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Sumbria, Rachita K, Grigoryan, Mher Mahoney, Vasilevko, Vitaly, Paganini-Hill, Annlia, Kilday, Kelley, Kim, Ronald, Cribbs, David H, and Fisher, Mark J
- Subjects
Biomedical and Clinical Sciences ,Neurosciences ,Immunology ,Brain Disorders ,Aging ,Animals ,Blood-Brain Barrier ,Calcium-Binding Proteins ,Cerebral Hemorrhage ,Disease Models ,Animal ,Encephalitis ,Female ,Glial Fibrillary Acidic Protein ,Lipopolysaccharides ,Male ,Mice ,Mice ,Inbred C57BL ,Microfilament Proteins ,Sex Factors ,Time Factors ,Animal models ,Cerebral microhemorrhage ,Cerebral microbleeds ,Inflammation ,Hemosiderin ,bacterium lipopolysaccharide ,eosin ,ferric ferrocyanide ,glial fibrillary acidic protein ,hematoxylin ,immunoglobulin G ,ionized calcium binding adapter molecule 1 ,membrane protein ,unclassified drug ,actin binding protein ,Aif1 protein ,mouse ,calcium binding protein ,lipopolysaccharide ,age ,aged ,aging ,animal experiment ,animal model ,animal tissue ,Article ,astrocyte ,blood brain barrier ,brain development ,brain hemorrhage ,C57BL 6 mouse ,cell activation ,cell disruption ,controlled study ,disease exacerbation ,female ,immunohistochemistry ,macrophage ,macrophage activation ,male ,microglia ,mouse ,nervous system inflammation ,nonhuman ,pathogenesis ,animal ,C57BL mouse ,chemically induced ,disease model ,encephalitis ,metabolism ,pathology ,pathophysiology ,sex factor ,time factor ,Clinical Sciences ,Neurology & Neurosurgery - Abstract
BACKGROUND:Cerebral microhemorrhages (CMH) are commonly found in the aging brain. CMH are also the neuropathological substrate of cerebral microbleeds (CMB), demonstrated on brain MRI. Recent studies demonstrate the importance of systemic inflammation in CMH development, but the relationships among inflammation, aging, and CMH development are not well-defined. In the current study, we hypothesized that the pathogenesis of inflammation-induced CMH in mice differs by age. METHODS:We studied young (3 months, n = 20) and old (18 months, n = 25) C57BL/6 mice injected with low-dose lipopolysaccharide (LPS; 1 mg/kg, i.p.) or saline at 0, 6, and 24 h. Seven days after the first LPS/saline injection, brains were harvested, sectioned, and stained with hematoxylin and eosin (H&E) and Prussian blue (PB) to estimate acute/fresh and sub-acute CMH development, respectively. The relationships between microglial/macrophage activation (ionized calcium-binding adapter molecule-1), astrocyte activation (glial fibrillary acidic protein), blood-brain barrier (BBB) disruption (brain immunoglobulin G), aging, and CMH development were examined using immunohistochemistry. RESULTS:Aging alone did not increase spontaneous H&E-positive CMH development but significantly increased the number, size, and total area of LPS-induced H&E-positive CMH in mice. LPS- and saline-treated aged mice had significantly larger PB-positive CMH compared with young mice, but the total area of PB-positive CMH was increased only in LPS-treated aged mice. Aged mice had significantly increased microglial/macrophage activation, which correlated with H&E- and PB-positive CMH development. Aged mice treated with LPS had significantly increased astrocyte activation and BBB disruption compared with young LPS-treated mice. CONCLUSIONS:Aging makes the brain more susceptible to inflammation-induced CMH in mice, and this increase in CMH with aging is associated with microglial/macrophage activation.
- Published
- 2018