A combination of drugs administered to protect Gulf War soldiers against disease and nerve gas may have inadvertently damaged their testes and sperm production, according to animal experiments conducted by Medical Center researchers.
Tests on rats have shown that equivalent doses of three drugs given to all Gulf War soldiers--the insect repellent DEET, the insecticide permethrin and the anti-nerve gas agent pyridostigmine bromide--cause extensive cell degeneration within various structures of the testes, far more than with any of the drugs taken separately.
"This research shows the chemicals could reduce the number of sperm, and the ones that remain could be less active, or even deformed," said Mohamed Abou Donia, a professor of pharmacology and cancer biology and lead author of the study, which was funded by the Department of Defense. "This could have a profound effect on fertility."
The damage was particularly severe when the cocktail of drugs was combined with moderate stress, which was simulated by keeping the mice immobilized for a short time, Abou Donia said.
"Of course, soldiers were stressed during the war, and people had the idea that Gulf War Syndrome was just complaints derived from stress," he said.
The study, published in the Jan. 10 issue of The Journal of Toxicology and Environmental Health, follows up earlier research by the same team that showed the combination of drugs also does significant damage to the brain and liver, and is a possible cause of another condition known as Gulf War Syndrome--a neurological disorder characterized by diminished memory, cognition and balance.
The new research has been urged on by veterans' groups, who have noted a prevalence of infertility and other sexual problems among Gulf War veterans.
Hagir Suliman, an assistant research professor in hyperbaric service and a co-author of the study, noted that the research should provide an impetus for the military to test drugs and drug combinations in the lab more extensively before giving them to soldiers.
"That will be the appropriate approach in the future," Suliman said. "Test it in mice-if there is any advanced effect, hold up on administering it, and go on to primate studies."
The researchers found the most pervasive cell damage within basal germ cells and spermatocytes, which develop into mature sperm but prematurely progressed toward cell death in the study.
"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 disease," explained Abou Donia in a statement. "But under a microscope, you can see clear and well-defined damage to a variety of testicular structures."
Suliman stressed that more research on the drugs' effects is needed. "Some more extensive studies need to be done related to sperm count," he said. Abou Donia plans to build on the study by adding the nerve gas sarin as another component.
Although he recommended renewed vigilance toward the drugs being given to soldiers, Abou Donia emphasized that the government should not be unduly blamed for the drug trio's deleterious effects.
"We should keep in mind that when the army administered these drugs, they had the best intentions, and for the most part, they were successful. Very few came back with any [communicable] diseases," Abou Donia said.
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