CHICAGO, Oct. 10 (Xinhua) -- Researchers have developed an implantable, biodegradable device that delivers regular pulses of electricity to damaged peripheral nerves in rats, helping the animals regrow nerves in their legs and recover their nerve function and muscle strength more quickly.
The device, the size of a quarter, wraps around an injured nerve and delivers electrical pulses for days before harmlessly degrades in the body. The device is powered wirelessly by a transmitter outside the body that acts much like a cell phone charging mat.
The researchers at Washington University School of Medicine and Northwestern University studied rats with injured sciatic nerves. This nerve sends signals up and down the legs and controls the hamstrings and muscles of the lower legs and feet.
They used the device to provide one hour per day of electrical stimulation to the rats for one, three or six days, or no electrical stimulation at all, and then monitored their recovery for the next 10 weeks.
Any electrical stimulation was better than none at all at helping the rats recover muscle mass and muscle strength. In addition, the more days of electrical stimulation the rats received, the more quickly and thoroughly they recovered nerve signaling and muscle strength.
"Before we did this study, we weren't sure that longer stimulation would make a difference, and now that we know it does, we can start trying to find the ideal time frame to maximize recovery," said co-senior author Wilson "Zack" Ray, an associate professor of neurosurgery, of biomedical engineering and of orthopedic surgery at Washington University.
By varying the composition and thickness of the materials in the device, the researchers can control the precise number of days it lasts before disintegrating. They are working now on creating new versions that can provide electrical pulses for weeks before degrading.
"There really are no therapeutic options for some of these nerve injury patients," Ray said. "This isn't a therapeutic option yet either, as it hasn't been tested in people. But I'm excited about it because it's a new approach to treating peripheral nerve injury, and it might offer a solution where really there is none today in the clinical realm."
Unlike neurons in the brain and spinal cord, the peripheral nerves that run through the arms, legs and torso can regenerate after injury. Electrical stimulation triggers the release of growth-promoting proteins, boosting nerve cells' natural abilities and helping them regrow faster and more completely.
The findings were published on Monday in Nature Medicine.