Effects of laser irradiation on the spinal cord for the regeneration of crushed peripheral nerve in rats

Background and Objective: The purpose of the present study nas to examine t he recovery of the crushed sciatic nerve of rats after low-power laser irra diation applied to the corresponding segments of the spinal cord. Study Design/Materials and Methods: After a crush injury to the sciatic ner ve in rats, low-power laser irradiation was applied transcutaneously to cor responding segments of the spinal cord immediately after closing the wound by using 16 mW, 632 nm He-Ne laser. The laser treatment was repeated 30 min utes daily for 21 consecutive days. Results: The electrophysiologic activity of the injured nerves (compound mu scle action potentials-CMAPs) was found to be approximately 90% of the norm al precrush value and remained so for up to a long period of time. In the c ontrol nonirradiated group, electrophysiologic activity dropped to 20% of t he normal precrush value at day 21 and showed the first signs of slow recov ery 30 days after surgery. The two groups were found to be significantly di fferent during follow-up period (P<0.001). Conclusion: This study suggests that law-power laser irradiation applied di rectly to the spinal cord can improve recovery of the corresponding insured peripheral nerve. <(c)> 2001 Wiley-Liss, Inc.