RESUMO
Background Previous studies have confirmed that nicotine exposure is an independent risk factor for miscarriage, but it is not clear whether nicotine causes unexplained recurrent spontaneous abortion (URSA) through oxidative stress. Objective To explore potential mediating effect of oxidative stress on the relationship between nicotine exposure and URSA. Methods Using a 1∶1 matched case-control study, 88 patients with URSA visiting Beijing Obstetrics and Gynecology Hospital affiliated to Capital Medical University from April to October in 2018 were selected as the case group, and 88 pregnant women without adverse pregnancy outcomes and seeking induced abortion in the outpatient clinic of the same hospital were selected as the control group. The levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-iso-prostaglandin F2α (8-iso-PGF2α) in urine were determined by enzyme-linked immunosorbent assay, and the level of urinary nicotine was determined by gas chromatography-mass spectrometry. Conditional logistic regression was used to analyze the associations of nicotine, 8-OHdG, and 8-iso-PGF2α with the risk of URSA. Multiple linear regression was used to analyze the association of nicotine with 8-OHdG and 8-iso-PGF2α. The potential mediating effect of oxidative stress on URSA after nicotine exposure was explored by dichotomous mediating model. Results The median concentrations (creatinine corrected) of nicotine, 8-OHdG, and 8-iso-PGF2α in urine of the case group were 7.78, 4.84, and 44.10 μg·g−1, respectively, while those of the control group were 6.48, 3.34, and 29.39 μg·g−1, respectively. The concentrations of nicotine, 8-OHdG, and 8-iso-PGF2α in urine of the case group were all higher than those of the control group (P < 0.05). The results of conditional logistic regression model showed that after adjusting selected confounding factors, compared with the Q1 groups of nicotine and 8-iso-PGF2α, the OR (95%CI) values of URSA in the Q4 groups were 4.20 (1.33-13.29) and 6.25 (1.66-23.59), respectively. Compared with the Q1 group of 8-OHdG, the OR (95%CI) values of URSA in the Q1, Q2, and Q3 groups were 5.47 (1.43-20.93), 4.24 (1.28-14.07), and 6.36 (1.82-22.28), respectively. The results of multiple linear regression showed that after adjusting confounding factors, there was a positive correlation between urinary nicotine and 8-OHdG in both the case group and the control group, and the b (95%CI) values were 0.76 (0.67-0.86) and 0.81 (0.67-0.95) respectively; there was a positive correlation between urinary nicotine and 8-iso-PGF2α in both the case group and the control group, and the b (95%CI) values were 0.65 (0.55-0.75) and 0.76 (0.64-0.87), respectively. The results of dichotomous mediating analysis showed that the mediating effect of 8-iso-PGF2α and its 95%CI on the relationship between nicotine exposure and URSA was 1.518 (0.749-2.311). Conclusion Internal nicotine exposure is a risk factor for URSA and is positively correlated with oxidative stress, and it may lead to URSA through lipid peroxidation damage.
RESUMO
8-iso-prostaglandin F2α is a stable end product of lipid peroxidation of cell membrane lipid arachidonic acid under oxidative stress,which is formed by non-enzymatic beta lysis and recombination.It is an ideal index for evaluating the degree of lipid peroxidation and damage.Oxidative stress can damage biological molecules,cause cell death and tissue damage,and participate in the process of Henoch-Schonlein purpura and kidney damage.This article reviews the oxidative stress state and lipid peroxidation process of the body,the production and significance of 8-iso-prostaglandin F2α,the mechanism of oxidative stress in the pathogenesis of Henoch-Schonlein purpura and renal damage,and the important clinical significance of measuring 8-iso-prostaglandin F2α for Henoch-Schonlein purpura,which will provide evidence for future targeted therapy.