Background: Paraoxonase 1 (PON1) is an enzyme attached to high density lipoprotein (HDL-C)
which has antioxidant and anti-atherogenic activities.
Objectives: In this study, we investigated the effects of alpha lipoic acid on PON1 activity, lipid
profile and atherogenic index as well as correlation between PON1 activities and HDL-C in
Materials and Methods: Thirty adult male rats were distributed in three experimental groups in
this study. Control (group I), diabetic (group II) and diabetic animals treated with alpha lipoic
acid (group III) group. Diabetes mellitus was induced in rats in groups II and III by a single
dose of alloxan monohydrate (100 mg/kg; subcutaneous) and then treatment was performed
with administration of alpha lipoic acid (100 mg/kg intraperitoneally) in group III for 6 weeks.
Blood samples were collected from animals to measure the levels of triglyceride (TG), total
cholesterol (TC), low density lipoprotein (LDL-C), HDL-C, PON1 activity and correlation the
between HDL-C and atherogenic index by PON1.
Results: Statistical analysis showed that alpha lipoic acid significantly (P<0.05) inhibited
the increase of TG, TC, LDL-C, VLDL, atherogenic index, atherogenic coefficient (AC),
and cardiac risk ratio (CRR) when compared to diabetic rats in group II. HDL-C level was
increased by alpha lipoic acid. The activity of PON1 was significantly (P<0.05) decreased in
diabetic rats and treatment with alpha lipoic acid increased the PON1 activity. Moreover, the
activity of PON1 correlated positively with HDL-C and negatively with AC, CRP 1 and CRP2.
Conclusions: This study demonstrated that the administration of alpha lipoic acid can improve
PON1 activity, lipid metabolism, atherogenic index and is able to reduce the risk of coronary
artery diseases and atherosclerosis in diabetic rats.