Infertility in endometriosis could be caused by oxidative stress-induced DNA damage, according to a study published in the journal Scientific Reports.
This suggests that reducing oxidative stress in the oocytes (cells in the ovaries that may mature to form an egg cell) may help treat infertility in endometriosis patients.
The authors of the study, “The sensitivity of the DNA damage checkpoint prevents oocyte maturation in endometriosis,” showed that levels of free-radical chemicals called reactive oxygen species (ROS), which are known to cause damage to the DNA, were elevated in the follicular fluid (which surrounds the egg cells in the ovaries) of endometriosis patients.
To investigate the effect of ROS on the maturation of the oocytes, researchers cultured immature oocytes obtained from young mice. The oocytes were cultured in follicular fluid from endometriosis patients, which led to the maturation rate of the oocytes to be reduced.
Scientists believe that ROS turns on the DNA damage-response pathway where a protein called ATM kinase is activated and halts cell division.
Researchers inhibited the activity of the ATM kinase protein to test whether the reduced rate of oocyte maturation that was observed when the oocytes were cultured was caused by ROS-induced DNA damage.
They saw that in the absence of ATM kinase, cell division was completed, suggesting that ROS are indeed responsible for the reduced oocyte maturation.
The researchers concluded that reducing oxidative stress in the oocytes might help treat endometriosis-associated infertility.
To test this hypothesis, they added two different antioxidants to the follicular fluid: resveratrol, a compound found in grapes and berry skin, and melatonin, also known as the sleeping hormone. Adding these led to the negative effects of ROS being decreased and more eggs maturing.
“We believe these results could have clinical implications for many women struggling to [get] pregnant,” Dr. Simon Lane, a research fellow at the University of Southampton in England and the senior author of the study, said in a press release. “More research is now needed to investigate whether the damage caused by endometriosis is treatable or preventable.”
Endometriosis affects around 10 percent of women worldwide and is sometimes associated with infertility and reduced IVF success rates.