Washington: A new animal model developed by researchers for the painful nerve condition sciatica should help doctors diagnose and treat it, according to a new study.

Its symptoms are numbness or pain from the lower back to the feet, radiating leg pain or difficulty in controlling the leg. It is often caused by compression, or pinching, of any of the five nerve roots that combine to make up the sciatic nerve.

Surgical simulation of nerve compression in rats was led by Mohammed Shamji, a Ph.D. graduate working at Duke University's Pratt School of Engineering.

Shamji and research fellow Kyle Allen observed that the animals' gait became asymmetric, and that they over-responded to temperature changes and touch in their limbs after the surgery.

They also found, for the first time, that the physical symptoms experienced by the affected animals seemed to be linked to an increase in levels of interleukin-17 (IL-17), a protein involved in regulating the inflammatory response.

Elevated levels of IL-17 have already been implicated in autoimmune diseases (when the body's own immune system turns against the host's body) as is the case in rheumatoid arthritis and asthma.

"This finding suggests a possible role for immune system activation in contributing to symptoms of Sciatica," said Shamji, according to a Duke release.

These results were published online in Spine. IANS