Jan. 10, 2003 -- Chemicals given to Gulf War soldiers to protect them from disease and chemical warfare more than a decade ago may now be responsible for some mysterious cases of infertility and sexual dysfunction. A new study suggests that the combination of chemicals may have potentially toxic effects on men's testes and sperm production, according to animal tests.
The study appears in the Jan. 10 issue of the Journal of Toxicology and Environmental Health and was funded by the U.S. Department of Defense.
Soldiers involved in the 1991 Gulf War were given a combination of insecticides (DEET and permethrin) to protect them against insect diseases as well as the anti-nerve gas agent pyridostigmine in case of a chemical warfare attack.
In their study, researchers gave equivalent doses of the same combination of agents to rats. They found that when the chemicals were given in combination, they caused extensive cell damage in the rats' testes.
In addition, the study showed that the negative reactions were most severe among rats that were exposed to stressful situations when they received their dose of the chemicals.
"It appears that moderate stress, combined with the three chemicals, caused the most severe deterioration in testicular structure and sperm production, and these conditions were likely experienced by some Gulf War soldiers in the combat environment," says study researcher Mohamed Abou Donia, PhD, a pharmacologist at Duke University, in a news release.
"Interestingly, the chemically treated rats don't look or behave any differently than normal rats, just as the soldiers don't show any outward signs of the disease," says Donia.
The types of cell damage seen could create problems with sperm production and interfere with the normal development of mature sperm.
Previous studies from the same research team found that these chemicals are much more toxic to rats' brains when given in combination rather than individually.
The researchers say this combination of the three chemicals "may have synergistic and/or additive effects resulting in severe testicular damage."