Effect of low‐power pulsed laser on peripheral nerve regeneration in rats

The purpose of this study was to determine whether low‐power pulsed laser irradiation could affect the regeneration of a 10‐mm gap of rat sciatic nerve created between the proximal and distal nerve stumps, which were sutured into silicone rubber tubes. After 8 weeks of recovery, pulsed laser‐irradiated groups at frequencies of 5 kHz and 20 kHz both had significantly lower success percentages of regeneration (50% and 44%, respectively) compared to sham‐irradiated controls (100%). In addition, qualitative and quantitative histology of the regenerated nerves revealed a less mature ultrastructural organization with a smaller cross‐sectional area and a lower number of myelinated axons in both pulsed laser‐irradiated groups than in controls. These results suggest that pulsed laser irradiation could elicit suppressing effects on regenerating nerves. © 2004 Wiley‐Liss, Inc. Microsurgery 25:83–89, 2005.