Effect of exercise training on oxidized LDL-mediated platelet function in rats

This study investigates how exercise training affects Oxidized LDL (Ox-LDL) mediated-platelet activation. Five-week-old male Wistar rats were assigned to either control or trained groups. Trained rats were treadmill-trained f or 10 weeks after familiarization. The following measurements were taken in both control and trained groups: Ox-LDL-mediated platelet aggregability an d [Ca2+](i), plasma and platelet-derived nitric oxide (NO) metabolite (nitr ite plus nitrate) levels, and antiaggregating activity of NO derived from e ndothelial cells. Based on those measurements, major findings in this study can be summarized as follows: 1) the trained group had a higher plasma -NO metabolite level than the control group; 2) the trained group had a lower platelet aggregability and [Ca2+](i) elevation and a higher platelet derive d-NO metabolite level than the control group; 3) the trained group had lowe r Ox-LDL-potentiated platelet aggregability and [Ca2+](i) elevation and Ox- LDL-attenuated NO metabolite in platelet than the control group; 4) treatin g the platelet with L-arginine inhibited Ox-LDL-potentiated platelet activa tion in both control and trained groups; 5) Ox-LDL enhances platelet aggreg ation directly although impairing NO bioactivity but not guanylate cyclase activity in both control and trained groups. Results in this study demonstr ate that exercise training decreases Ox-LDL-potentiated platelet activation most likely by enhancing platelet-derived NO release.