Expression and significance of thioredoxin system in placenta of preeclampsia

Abstract

Objective To assess the expression of thioredoxin reductase （TR） and thioredoxin （Trx） mRNA, TR activity in human placenta in women with preeclampsia, and to discuss the relationship between Trx system and the pathogenesis of preeclampsia. Methods Twenty-six women with preeclampsia （10 mild and 16 severe） and 28 healthy gravidas （control） were included in this study. Semi-quantitative reverse transcription polymerase chain reaction （RT-PCR） were employed to demonstrate the expression of TR and Trx in placentas. TR activity was measured spectrophotometrically. Results The expression of TR mRNA （mild： 0. 865 ± 0. 018; severe： 0. 800±0. 025, P〈0.05） and Trx mRNA （mild： 0. 873±0. 008; severe： 0. 818±0. 025, P〈0.05） were lower in placenta of preeelampsia than in the control group （TR mRNA： 0. 893±0. 023; Trx mRNA： 0. 918±0.023. P〈0.05）, and those levels in the severe preeclampsia group were lower than in the mild ones. Both the mild and severe preeclampsia groups showed lower TR activity than the control （mild： 17.732±1.653; severe： 15. 626±1.543 vs 19. 770±2.432, P〈0.05）, and that of the severe preeclampsia group was lower than that of the mild ones. Positive correlation was found between the TR activity and TR mRNA expression in both groups （r = 0. 612, P〈 0. 001）. Conclusions Abnormal decreased expression of TR mRNA and Trx mRNA and TR activity in human placenta of preeelampsia might participate and play an important role in the pathogenesis of preeclampsia. Key words: Preeclampsia; Thioredoxin; Thioredoxin reductase; Oxidative stress