Dynamics of urinary oxidative stress biomarkers: 8-hydroxy-2'-deoxyguanosine and 8-isoprostane in uterine leiomyomas

BACKGROUND: Perturbations of antioxidant levels and lipid peroxidation, but not oxidative DNA damage as a biomarker of oxidative stress have been reported in uterine myoma patients. AIMS: The study aimed at examining the patterns and influence of oxidative stress/damage biomarkers, 8-isoprostane (8-IP) and 8-hydroxy-2'-deoxyguanosine (8OHdG), on the ovulatory and luteal phases of normal and fibroid women. SETTINGS AND DESIGN: Twenty women diagnosed of fibroids (1–5 years) and 20 nonfibroid women were age-matched. Selection was randomly done at the National Obstetrics and Gynaecology Department. SUBJECTS AND METHODS: Three successive samples of urine were taken at 8:00 am on the 14(th), 18(th), and 21(st) days of the menstrual cycle. Mid-stream urine was collected from subjects, after they had cleaned genitals. The samples were kept in an ice chest, transported to the laboratory, and stored at − 70°C until the time of analysis. Samples were analyzed by ELISA technique using commercial kits for 8OHdG and 8-IP. Results were calculated using a computer program. STATISTICAL ANALYSIS USED: Statistical Package for Social Sciences, version 20.0, was used for data management and statistical analysis. The results were expressed as mean ± standard deviation. Differences in continuous data were compared using Student's t-test (two groups) and one-way ANOVA (three or more groups) followed by Bonferroni post hoc test. Relationship between variables was ascertained by Spearman's correlation coefficient. All results were considered significant at 5% level of probability. RESULTS: Significant differences were observed between day 14 and day 21 in control and test groups' estrogen levels (P = 0.0047 and P = 0.004, respectively). Significant progesterone differences were observed between control and test groups on the same days (P = 0.002 and P = 0.001, respectively). A positive correlation was observed between day 21 estrogen and progesterone levels (P = 0.0003) of the control group. Test group had higher levels of 8-IP and 8OHdG than control groups on day 21, with 8OHdG at maximum in the test group but minimum in the control group. The influence of 8OHdG was seen by a negative correlation with estrogen and progesterone on day 21 (P = 0.0002) and a positive correlation between 8OHdG and 8-IP on the same day in the test group. Finally, there was a positive correlation between 8-IP and 8OHdG on day 14, but a negative correlation on day 21 (P = 0.0016). CONCLUSIONS: Oxidative damage was absent in the control group but was very much present in the test group on day 14 and day 21 with progesterone and estrogen acting in concert with oxidative damage biomarkers. An inverse pattern of biomarkers was observed between control and fibroid groups. Oxidative stress biomarkers influenced hormonal levels and pattern of the fibroid group.