That’s the contention of a new Duke University study, published in the Journal of Toxicology and Environmental Health, that showed the chemicals caused extensive cell degeneration and cell death in the testes of laboratory rats.
Rats given the chemicals and exposed to stressful situations suffered more extensive damage. This suggests that the chemicals, combined with the moderate stress likely experienced by some soldiers during the 1991 Gulf War, caused the most severe deterioration in testicular structure and sperm production, says Mohamed B. Abou-Donia, a Duke pharmacologist and the study’s lead researcher.
The findings could provide clues about why some veterans of the Persian Gulf War have suffered from infertility and sexual dysfunction, Abou-Donia says.
Researchers gave lab rats the insect repellant DEET, the insecticide permethrin and the anti-nerve gas agent pyridostigmine bromide in doses designed to mimic the human equivalent of what the soldiers received.
The rats showed no outward signs of ailments, Abou-Donia says, but under a microscope, the testicular damage could clearly be seen. As a result, he suggests, cases of testicle damage among soldiers could have been overlooked.
“In the real-life situation, veterans came back and looked normal, and the only way doctors could tell damage was to look at the testes,” Abou-Donia says. “So they ended up saying it [concern about infertility] was all in the veterans’ heads, only their imaginations.”
Earlier studies found much higher doses of each of the three chemicals given separately proved almost harmless, Abou-Donia says. Combining two of them was more toxic, and the three together, the most toxic, he says.
However, Abou-Donia adds the results of the latest research, which examined the rats immediately after giving them the chemicals and subjecting them to stress, doesn’t answer whether the damage is reversible. Further study would be needed to determine the possibility of recovery, he says.
In the study, financed by the U.S. Department of Defense, the researchers found the most pervasive cell damage within basal germ cells and spermatocytes, which develop into mature sperm. The three chemicals combined with stress caused these cells to detach from one another, slough off and develop holes known as “vacuoles,” part of the process that leads to cell death. And the more cells that die, the more sperm production is reduced, Abou-Donia says.
Similar cell degeneration occurred in the seminiferous tubules, where developing sperm are produced, and in Sertoli cells that support and nurture the developing germ cells, Abou-Donia says.
The study showed the chemicals and stress interrupted most of the stages of sperm development and eliminated some altogether.
Steve Robinson, a Gulf War veteran who is now executive director of the National Gulf War Resource Center, an information clearinghouse, says the study’s findings come as no surprise.
“Although this particular study is unfortunate news, it’s confirmatory news,” Robinson says. “It will at least close the door so [veterans] know the reason.”
Robinson, who researched Gulf War-related illnesses for the Defense Department until 2001, says he hears regularly from Gulf War veterans concerned about infertility.
“It’s been on veterans’ minds,” he says. “The evidence is mounting that exposure from the Gulf War is the reason why veterans are sick, and veterans have been saying this all along. But science is just now catching up.”
As the United States prepares for a potential second round of war in Iraq, Robinson says the study demonstrates the need for caution in giving soldiers chemicals.
“I think what it says is number one, we have to be extremely concerned about the use of investigational new drugs and vaccines in combination with pesticides used in military applications during war,” Robinson says.
For more information, go to the National Gulf War Resource Center web site at http://www.ngwrc.org