"In essence, these signals warn other cells to harden their defenses," Dr. Naviaux explains. "This helps protect against cell-to-cell infection. However, it may also interfere with cell-to-cell communication."
Normally, healthy cells stop releasing these danger signals when an infection or other stress resolves. According to Dr. Naviaux's "cell danger response" theory, autism can result when a stress during early brain development triggers a chronic danger response. The stress that starts this chain of events can come from an environmental influence, a genetic problem or a combination of both, he proposes. The result is chronic brain inflammation and frayed connections between brain cells. "When the brain cells stop talking, so do children," he says.
Dr. Naviaux's team produced litters of mice that exhibited autism symptoms by mimicking a viral infection in their mothers during pregnancy. This "maternal immune activation mouse model" is well-known for producing mouse offspring with symptoms of autism and schizophrenia.
The researchers measured social behavior by giving the mice opportunities to spend time with either another mouse or a Lego block in adjacent wire chambers. They also tested motor coordination as the mice walked along a rotating rod. While female pups showed only mild impairments, the male pups showed a 50 percent reduction in socializing and a 28 percent reduction in motor coordination. The researchers then tested the male pups' response to treatment. When the mice were 6 weeks old (roughly adolescents), 84 received an injection of suramin, a ch
|Contact: Jane E. Rubinstein|