A study conducted by Hiroshima University in Japan has identified and blocked a specific molecule involved in maintaining pain after a nerve injury.
Researchers at the university initiated investigation of sciatic nerve pain as part of their long-term studies of the central nervous system.
Sciatic nerve pain, or sciatica, causes pain in the lower back, buttocks, or back of the leg and is often caused by a herniated disc in the spine or a pinched nerve. Similar pain can occur in different nerves in patients with cancer or diabetic neuropathy.
During the study, researchers administered a drug to mice with an injury to their sciatic nerve.
Following multiple injections of a drug that blocks the activity of a molecule called high-mobility group box-1 (HMGB1), researchers found significant decrease in pain in mice.
The anti-HMGB1 was injected into the hip of the mice, in the slightly broader area around the nerve.
Furthermore, a single dose of a drug to block the activity of a different molecule, called matrix metalloprotease-9 (MMP-9), could also provide relief from the pain.
The chemical pathways that these drugs use to inhibit HMGB1 or MMP-9 are believed to be different from common pain relievers, e.g. opioids (Morphine) or acetaminophen (Tylenol), thereby reducing the chances of addiction or negative side-effects.
Blocking HMGB1 alleviated pain with no negative impact on healing and selectively blocking MMP-9 also relieved pain, with no obvious changes to the activity of other molecules responding to the injury.
Image: Mice received injections of drugs that specifically block the activity of two different molecules. Photo: courtesy of Hiroshima University.