The nerve conduits created by IIT Guwahati researchers and implanted in rats with sciatic nerve injury showed functional recovery

Very often injuries and even surgical interventions to take care of injuries inflict equal damages. The collateral loss of a medical operation often is severed nerves.

Researchers at the Indian Institute of Technology (IIT) Guwahati, seem now to have a grip on the matter. They have found a way of treating peripheral nerve damage which can result from injuries.

This is of great significance in a country like India where medical tourism is a billion dollar industry.

The nerve conduits created by the researchers and implanted in rats with sciatic nerve injury showed functional recovery one year after implantation.

The team was led by Prof Utpal Bora from the Department of Bio-sciences and Bio-engineering. "They synthesized nerve passages by electro-spinning a mixture of silk protein called fibroin and an electrically conductive polymer called polyaniline. To produce tubular shaped nerve conduits, the scientists rolled the electro-spun sheets many times over a stainless steel spindle," reports The Hindu.

In tissue engineering, silk fibroin protein is used as a sort of skeleton supporting other materials. But silk is not electrically conducive; the nerves conduits are. "Since silk is not electrically conductive, we coated it with polyaniline nanoparticles, which are a good electrical conductor," says Dr Suradip Das from the Department of Bio-sciences and Bio-engineering at IIT Guwahati, and the first author of the paper. The results were published in the journal, Biomedical Materials, and are now in the public domain.

Nerves behave like electrical wires where the conducting portion of the nerves is covered with myelin, which is a fatty white substance, a sort of insulation secreted by cells called Schwann cells. Cells are an incredibly complicated business, so don't ask how they produce organic material for neurological functioning. That is another story.

To fabricate myelin, the Schwann cells were cultured on the conduits. The Schwann cells were found to grow between the multiple layers of silk fibroin-polyaniline composite, and also on the surface and inside of the conduit. The myelin sheath "Acts as biological insulators and play a crucial role in nerve regeneration," Dr Das is quoted as saying.

To test how well the lab-nerve conduit helped in nerve regeneration, the researchers removed 10 mm of sciatic nerve from rats and implanted the conduit they created. The surgical area was reopened after 12 months. You will note how the much maligned rats are so crucial to our health in this respect.

Compared with untreated animals where the nerve gap was found to have grown further, the conduits in the treated animals showed no deformation. All the composite parts of a nerve were found to have grown in the implanted material, including the myelin sheath in the regenerated tissue. Clearly, then the artificial conduit helped initiating and enhancing the quality of regeneration across the nerve gap.

Rats with regenerated sciatic nerve showed better walking pattern compared with other groups in the study. "This shows that our work could restore a lot of the sciatic nerve functions in rats," Dr Das says.

There is a growing demand for nerve implants but there are no indigenously developed nerve conduits available in India. "Our efforts take care of that," Prof Bora says. Dr Kushal K. Sarma from the College of Veterinary Science, Khanapara, Guwahati, is among the authors of the paper.