Plasma paraoxonase 1 arylesterase activity in D-galactose-induced aged rat model: correlation with LDL oxidation and redox status.
OBJECTIVE
There is much evidence linking the involvement of oxidative stress in the pathogenesis of aging. Paraoxonase 1 (PON1) is an HDL-associated antioxidant enzyme that inhibits the oxidative modification of low-density lipoproteins (LDL). We have investigated the changes in plasma PON1 activity, LDL oxidation, radical scavenging activity and lipid peroxidation in D-galactose-induced aging rat model and also compared the results with 24-month naturally aged rats.


METHODS
Arylesterase activity of PON1, susceptibility of LDL for oxidation, plasma radical scavenging activity and plasma thiobarbituric acid reactive substances (TBARS) were measured in normal control rats (4-months-old control rats subjected to D-galactose-induced experimental aging, and 24-month-old naturally aged rats).


RESULTS
There was a significant decrease in plasma PON1 arylesterase activity in both subcutaneous D-galactose-treated groups and 24-month-old aged rats (P < 0.05, for each). TBARS, an oxidative stress marker, was seen to increase in the experimental groups (P < 0.01). In both subcutaneous galactose-treated and naturally aged rats, there was a significant rise in plasma LDL oxidation (P < 0.05, for each). However, radical scavenging activity was decreased significantly (P < 0.01) in both groups, as compared to control.


CONCLUSIONS
The D-galactose-induced rat model of aging mimics the naturally aged rat with reference to PON1 arylesterase activity and susceptibility to LDL oxidation. The results emphasize the importance of PON1 with respect to aging and its association with redox balance of the body.
Department of Biochemistry, University of Allahabad, Allahabad, UP, 211002, India.
Dileep
D
Kumar
Syed Ibrahim
SI
Rizvi
D000375:Aging / Q000097:blood* / Q000187:drug effects; D000818:Animals; D043303:Aryldialkylphosphatase / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D005690:Galactose / Q000633:toxicity; D015227:Lipid Peroxidation / Q000187:drug effects; D008077:Lipoproteins, LDL / Q000097:blood*; D008297:Male; D023421:Models, Animal; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
D015415:Biomarkers; D008077:Lipoproteins, LDL; D017392:Thiobarbituric Acid Reactive Substances; C099252:oxidized low density lipoprotein; C572204:Pon1 protein, rat; D043303:Aryldialkylphosphatase; D005690:Galactose