The effects of regular aerobic exercise training on blood nitric oxide levels and oxidized LDL and the role of eNOS intron 4a/b polymorphism

Abstract

Background: Nitric oxide (NO), oxidized LDL (OxLDL) and endothelial nitric oxide synthase intron 4a/b polymorphism (eNOSP) are related to atherosclerosis (AS). The present study investigated the effects of regular aerobic exercise training on the mentioned risk factors as well as blood lipids and lipoproteins (BLLPs) and the role of eNOSP, which is unclear.

Methods: The study was participated by 46 well trained male soccer referees as the athletic group (AG, age; 23.26 ± 2.84 years) and 43 sedentary controls (CG, age; 23.16 ± 3.28 years). Yoyo intermittent endurance (Yoyo IE-2 test) was performed to measure aerobic endurance levels of the participants. Serum NO, eNOS and oxidized LDL (OxLDL) levels (by ELISA method) and total oxidant /antioxidant status ratio (/TOS/TAS) as oxidative stress (OS) index (OSI) and BLLPs levels were determined. eNOSP was identified from genomic DNA samples with VNTR analysis.

Results: There is no significant difference between AG and CG including the genotype groups for NO, eNOS and BLLPs and eNOSP has no role. However, AG's NO (29%, p > .05) and TAS levels were significantly higher (p = .001) than those of CG, whereas OSI (p = .001) and OxLDL (p = .011) values were significantly lower. On the other hand, NO value of the athletic bb group was 29% higher compared with the control and the a carrier (aC = aa + ab) group.

Conclusions: These findings suggest that regular aerobic exercise improves blood NO levels and antioxidant capacity, while decreasing OS levels including OxLDL, but not eNOS and BLLPs in the athletes. Although the polymorphism does not have a modifying effect on these effects, bb genotype group may benefit more from training for NO than aC group due to genetic tendency.

Keywords: Aerobic exercise; Endothelial nitric oxide intron 4a/b polymorphism; Nitric oxide; Oxidative stress; Soccer referee.