Abstract: Objective This study measures the glutaredoxin (Grx) gene and protein expression in umbilical vein endothelial cells upon exposure to Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS). The involvement of the Aktsignaling pathway is also determined. Methods EA-hy926 cells were pretreated with 1 000 ng·mL^-1 P. gingivalis LPS for 4, 12, 18, and 24 h, and then real-time reverse transcription polymerase chain reaction was employed to detect Grx1 expression. The effect of Grx on Akt activity was investigated using Western blot for the control, LPS (1 000 ng·mL^-1 LPS), and carmustine (BCNU) groups (1 000 ng·mL^-1 LPS, and the EA-hy926 cells were pretreated with 25 μmol·mL^-1 BCNU for 30 min). Results Gene expression of Grx1 significantly increased in LPS group compared with that in the control group. The Grx1 expression reached the peak level in 12 h, and the variation between the expression in 4 and 12 h was significant (P<0.05). After 12 h, the protein levels of Grx and phosphorylated-Akt (p-Akt) significantly increased in the LPS group (P<0.05), whereas the BCNU group showed a considerable decrease in both Grx and p-Akt expression levels (P<0.05). Moreover, a slight difference was observed in the total Akt protein levels in the three groups (P>0.05). Conclusion Grx expression increased upon exposure of EA-hy926 cells to the LPS. Akt activity could be inhibited by BCNU (a Grx inhibitor), which indicated that Akt might act as a downstream regulator of Grx.

Key words: Porphyromonas gingivalis, lipopolysaccharide, glutaredoxin, Akt, oxidative stress