RESUMO
AIM: Our purpose was to investigate lipid peroxide levels, total peroxyl radical-trapping anti-oxidative parameter (TRAP) values, and anti-oxidant vitamin levels in umbilical venous plasma and placental tissues, and to evaluate their roles in the pathophysiology of pre-eclampsia. METHODS: Samples of umbilical venous plasma and placental tissue homogenates were obtained from 23 normal and 18 pre-eclamptic women at between 33 and 40 weeks' gestation. The enzyme-linked immunosorbent assay method was used to assay alpha-tumor necrosis factor (TNF-alpha), and lipid peroxide levels were measured by thiobarbituric acid reaction. The TRAP values were measured using the modified Wayner's method. Ascorbic acid, retinol alpha-tocopherol and gamma-tocopherol were measured by high performance liquid chromatography. RESULTS: Levels of TNF-alpha in placental tissue homogenates of women with pre-eclampsia were significantly higher than those of women with normal pregnancy (21.4 +/- 3.39 v. 10.3 +/- 1.06 pg/mL, P < 0.05). Lipid peroxide levels in umbilical venous plasma and placental tissue homogenates of women with pre-eclampsia were significantly higher than those of women with normal pregnancy (10.3 +/- 1.1 v. 5.85 +/- 0.53, P < 0.01, 5.14 +/- 0.40 v. 3.99 +/- 0.33 nmol/mg protein, P < 0.05, respectively). The TRAP values in umbilical venous plasma and placental tissue homogenates of women with pre-eclampsia were significantly lower than those of women with normal pregnancy (0.39 +/- 0.02 v. 0.45 +/- 0.02, P < 0.05, 0.27 +/- 0.02 v. 0.34 +/- 0.03 mM, P < 0.05, respectively). Ascorbic acid levels in umbilical venous plasma and placental tissue homogenates of women with pre-eclampsia were significantly lower than those of women with normal pregnancy (325.4 +/- 50.4 v. 543 +/- 73.8, P < 0.05, 219.0 +/- 21.0 v. 333.3 +/- 32.6 nmol/mL, P < 0.05, respectively). CONCLUSIONS: The above results suggest that increased oxidative stress in the placenta is involved in the pathophysiology of pre-eclampsia, and ascorbic acid may act as an important preventative factor in the development of pre-eclampsia.
