Botulinum toxin could offer an efficient brand-new treatment for two forms of neuropathy — pain caused by various types of nerve injury, according to an experimental study published in Anesthesia & Analgesia.
Treatment along with botulinum toxin type B (BoNT-B) produces lasting reduction in abnormal pain responses caused by bodily nerve injury or chemotherapy-related nerve damage in mice, reports Tony L. Yaksh, Ph.D., of University of California, San Diego, and colleagues. Their study shows differing effects of local versus spinal injection of botulinum toxin and lends brand-new insights in to the molecular-degree explanations for exactly how “Botox” works to affect pain processing.
Further Studies on Botulinum Toxin’s Effects on Pain Responses
Building on previous studies, the researchers performed experiments in mice to evaluate the effects of BoNT-B on exaggerated pain responses to touch (allodynia) in one or the 2 hind paws after nerve injury. Mononeuropathy (single nerve injury) was induced by cutting a single spinal nerve and polyneuropathy (multiple nerve injury) by giving the chemotherapy drug cisplatin.
For the 2 types of neuropathy, the study evaluated the effects of injecting BoNT-B directly in to the affected paw or in to the spine (intrathecal injection). Botulinum toxin is most familiar from the use of BoNT-A — frequently known by the trade name Botox — for cosmetic plastic surgery. the 2 BoNT-A and BoNT-B are used for treatment of various neuromuscular disorders.
Over the past decade, BoNT-A has actually been successfully used to treat certain chronic pain syndromes. Because botulinum toxin sets off temporary muscle paralysis, the pain-lowering effects have actually been attributed to muscle relaxation. However, recent studies have actually suggested that various other analgesic mechanisms might be operating as well.
In mononeuropathy, injecting BoNT-B in to the affected paw significantly low abnormal pain responses. In polyneuropathy, local BoNT-B injection low allodynia in the injected paw only. This shows that the effects of locally injected botulinum toxin aren’t because of a lot more general spread of the toxin.
The reduction in allodynia after local BoNT-B injection lasted concerning two weeks prior to wearing off. That’s consistent along with the temporary effect of botulinum toxin used for various other purposes — the injections need to be repeated to sustain the useful effects.
In polneuropathy, intrathecal injection of BoNT-B relieved the allodynia on the 2 affected sides. Spinal BoNT-B didn’t transform normal reflexes in the paws, and didn’t transform various other types of pain perception.
Cellular-degree studies showed that both types of BoNT-B injection had differing effects in the pain-processing centers of the spinal cord. The outcomes offered brand-new insights in to the personal molecular targets involved in local and intrathecal injection.
Neuropathies are common and difficult-to-treat chronic pain problems. Mononeuropathy outcomes from nerve injury of several feasible sets off — for example, spinal cord injury or various other trauma. Polyneuropathy can easily occur as a toxic effect of chemotherapy drugs, even though diabetes is the most common cause.
The findings include to previous studies suggesting that botulinum toxin could be a helpful brand-new approach to treating neuropathic pain. They aid in learning BoNT’s mechanisms of action in mononeuropathy versus polyneuropathy, as well as the differing effects of local and spinal injection.
The study is additionally one he very first to concentrate on BoNT-B, which is shorter-acting compared to BoNT-A. Dr. Yaksh and colleagues conclude, “Further job focusing on transport and uptake of these and various other BoNT serotypes will certainly most likely give vital insights in to the mechanisms whereby these toxins exert their effects upon nociceptive [pain] processing.”