7-Hydroxycholestrol as a possible biomarker of cellular lipid peroxidation: difference between cellular and plasma lipid peroxidation.

Polyunsaturated fatty acids and their esters are known to be susceptible to free radical-mediated oxidation, whereas cholesterol is thought to be more resistant to oxidation. In fact, it has been observed that in the case of plasma lipid peroxidation, the amount of oxidation products of polyunsaturated fatty acids such as linoleic acid was higher than that of cholesterol. In contrast, during oxidative stress-induced cellular lipid peroxidation, oxidation products of cholesterol such as 7-hydroxycholesterol (7-OHCh) were detected in greater amounts than those of linoleates such as hydroxyoctadecadienoic acid (HODE). There are several forms of oxidation products of cholesterol and linoleates in vivo, namely, hydroperoxides, as well as the hydroxides of both the free and ester forms of cholesterol and linoleates. To evaluate these oxidation products, a method used to determine the lipid oxidation products after reduction and saponification was developed. With this method, several forms of oxidation products of cholesterol and linoleates are measured as total 7-OHCh (t7-OHCh) and total HODE (tHODE), respectively. During free radical-mediated lipid peroxidation in plasma, the amount of tHODE was 6.3-fold higher than that of t7-OHCh. In contrast, when Jurkat cells were exposed to free radicals, the increased amount of cellular t7-OHCh was 5.7-fold higher than that of tHODE. Higher levels of t7-OHCh than those of tHODE have also been observed in selenium-deficient Jurkat cells and glutamate-treated neuronal cells. These results suggest that, in contrast to plasma oxidation, cellular cholesterol is more susceptible to oxidation than cellular linoleates. Collectively, cholesterol oxidation products at the 7-position may be a biomarker of cellular lipid peroxidation.

7?-Hydroxycholesterol Reduces the Extent of Reactive Gliosis Caused by Fe~(3+)in Rat Brain / 中国医师杂志

Objective To demonstrate anti-proliferative effect and significance of 7?-hydroxycholesterol(7? OHCH) on astrocytes.Methods Ferric chloride were given with a cortical injection rats,then immediatedly infused liposome suspension including 7? OHCH in the injury site.Glial fibrillary acidic protein(GFAP) expression in cortex was detected quantitatively by immunohistochemistry and computerized image analysis.Results The number of GFAP positive astrocytes around the injury site was decreased to baseline.Conclusions 7?-OHCH has anti-proliferative property on astrocytes,and this could facilitate the investigation on the influences of reactive gliosis on functional recovery following brain injury and other kinds of pathogenesis involving glial cell proliferation.

7?-hydroxycholesterol reduces the extent of reactive gliosis caused by Fe~(3+) in rat brain / 临床神经病学杂志

Objective To demonstrate anti-proliferative property and significance of 7?-hydroxycholesterol(7?OHCH)on astrocytes after brain injury.Methods The rats were given a cortical injection of ferric chloride, then immediately infused liposome suspension with or without 7?OHCH in the injury site. Glial fibrillary acidic protein(GFAP) expression in cortex detected quantitatively with immunohistochemistry and computerized image analysis.Results A mass of inflammatory cells infiltrated and the number of GFAP positive astrocytes increased greatly around the injury site in rats with injection of iron,whereas the structure of cortex and the number of GFAP positive astrocytes around the injury site in the rats with injection of iron and 7?OHCH were as same as normal control.Conclusion 7?OHCH has anti-proliferative property on astrocytes, and this will provide a new way to prevent reactive gliosis and facilitate brain functional recovery following brain injury.