Changes of free cholesterol and neutral lipids after transient focal brain ischemia in rats
We investigated temporal and spatial changes of free cholesterol (FC) and neutral lipids (NLs) after brain ischemia with filipin complex staining to detect mainly FC and Nile Red staining for NLs such as cholesteryl ester (CE) and triacylglyceride (TAG).
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Changes of free cholesterol and neutrallipids after transient focal brain ischemia in rats H. Kamada, K.Sato, M. Iwai, K. Ohta, I. Nagano, M. Shoji, and K. Abe Department of Neurology, G raduate School of Medicine and Dentistry , Okayama University, Jap an
Summary We investigated temporal and spatial changes of free cholesterol (FC) and neutrallipids (NLs) after brain ischemia with filipin complex staining to detect mainly FC and Nile Red staining for NLs such as cholesteryl ester (CE) and triacylglyceride (TAG). Filipin stanining decreased during I to 7 d and lost at 21 d after transient middle cerebral artery (M CA) occlusion in the ischemic core, but did not change in the penumb ra. Nile Red positive dropl ets reached the maximum at 7 d after transient MCA occlusion (MCAO) and gradually decreased in the core, while the peak time delayed in the penumbra. Most Nile Red positive droplets were double positive for ED I in the core, and were localized within GFAP positive cells in the penumb ra. The present study suggests that chang es of FC and NLs are different tempor ally and spa tially between the ischemic core and the penumbra in relation to degenerative and regenerative neural processes following brain ischemia. Macrophag es and astrocy tes are presumed to play import ant roles in lipid metabolism for neural reorganization of the ischemic brain injury in the ischemic core and the penumbr a, respectively. Key words: Cholesterol; lipid; brain ischemia; rat. Abbreviations ApoE apolipoprotein E; A PP amyloid precursor protein; CBF cerebral blood flow; CE cholesteryl ester; CNS centr al nervous system; FC free cholesterol; FFAs free fatt y acids; M CA middle cerebral artery; M CAO middle cerebral artery occlusion; N Ls neutrallipids; PB phosphate buffer; PBS phosph ate-buffered saline; TAG triacylglyceride.
Introduction Neural membr anes are mainly composed of lipids (cholesterol and phospholipids) and many species of proteins. Similar to other somatic cells, neurons maintain cholesterol homeostasi s by regulating supply and efflux of cholesterol [3]. Under physiological condition , majority of free cholesterol (Fe) is provided by de novo synthesis from acetyl-CoA or by hydrolytic release from cholesteryl ester (CE) within the CNS,
while little FC is imported from systemic circulation. Triacylglyceride (TAG) plays an important role in providing free fatty acids (FFAs) for phospholipid synthesis [14]. Changes in cholesterol balance across cells affect both the rate of processing of ~-amyloid precursor protein (APP) and the level of Apolipoprotein E (ApoE) . ApoE-knock out mice showed slower clearance of infarct tissue after brain ischemia than wildtype mice [8]. Thu s, cholesterol metabolism plays an important role in the pathologic al conditions including Alzheimer's disease and brain ischemia. However, cholesterol and neutrallipids (NLs) metabolisms after brain ischemia have not been well clarified. In the present study, therefore , possible temporal and spatial changes of FC and NL s were
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