[Alpha lipoic acid affect the function of EPCs incubated by high-glucose]

EPCs were cultured in high-glucose-medium to induce oxidative stress. Concentration of malonaldehyde (MDA) and nitrogen monoxidum (NO) in culture medium were measured. The function of EPCs and protein expression of GPx-1 and eNOS were determined. Antioxidant alpha lipoic acid (ALA) was used as an intervention factor to explore the mechanism by which glucose induces the damage of EPCs.

EPCs were isolated and cultured from 15 Wistar rats (180-200 g). After planted for 4 days and 24 hours of attachment, cells were treated in 3 conditions: normal control group (NC) were cultured with 5 mmol/L glucose; high-glucose group (HS) were cultured with 30 mmol/L glucose; ALA group were cultured with 30 mmol/L glucose+ ALA(40 μg/L). Protein and gene expression of GPx-1 and eNOS were determined by Western blot and reverse transcription(RT-PCR); NO, MDA levels in culture medium were measured after 48 hours of treatment.

(1) Effect of different treatment on the secretion of MDA in EPCs: MDA levels in medium treat with high glucose (HS group) after 48h was significantly higher than that in NC group (P<0.05) and decreased after ALA intervention. (2) Effect of different treatment on the protein expression of GPx-1 in EPCs: Protein expression of GPx-1 was significantly lower in EPCs treated with high glucose than that in NC group after 48 hours of treatment while significantly normalized after ALA intervention (P<0.05). (3) Effect of different treatment on eNOS expression and NO secretion: eNOS expression was significantly lower in EPCs treated with high glucose than that in NC group after 48 hours of treatment (P<0.05). NO levels in medium was lower in HS group than in NC group (P<0.05). eNOS expression and NO level were increased after ALA intervention compared with HS group(P<0.05).

High-glucose culture induces oxidative stress in EPCs, EPCs cultured in high-glucose medium displays an impaired function shown as an lower anti-oxidative capacity, decreased eNOS expression and NO secretion, Impaired anti-oxidative capacity and NO secretion by high-glucose treatment can be improved by ALA intervention.