In vitro frog sciatic nerve as a peripheral nerve model for studies of the mechanism of action of low energy lasers: Part one.
OBJECTIVE
There have been numerous reports of modulation of peripheral nerve action potential characteristics through application of low energy laser irradiation (LELI), although no mechanism has yet been advanced to explain these observations. In order to investigate the mechanism of LELI effects in peripheral nerve tissue, a well-characterized, reliable, and robust peripheral nerve preparation is required. The objective of this study was to evaluate the in vitro frog sciatic nerve as a candidate model for future LELI mechanism studies.


METHODS
Following 60-minute baseline recordings of compound action potential (CAP) amplitude, latency, depolarization rate, and repolarization rate, helium-neon (HeNe) laser irradiation (632 nm, 15 min, 1-7 J, 44-320 J/cm2) was delivered to one of two sites on the nerve. Laser-induced changes in CAP parameters were analyzed during irradiation and for 60 minutes post-irradiation using a repeated measures linear regression model.


RESULTS
In the treatment group that received 7 J of HeNe energy over the recording electrode, CAP latency increased relative to nonirradiated controls during the postirradiation period. No other treatment group demonstrated laser-induced changes in CAP characteristics at any time during the experiment.


CONCLUSIONS
HeNe irradiation demonstrated limited ability to alter the CAP under these conditions. As such, the in vitro frog sciatic nerve is an inappropriate model for mechanism of action studies.
Ebert
D W
DW
Biomedical Engineering Center, Ohio State University, Columbus, USA.
Roberts
C
C
D000200:Action Potentials / Q000528:radiation effects; D000818:Animals; D066298:In Vitro Techniques; D007834:Lasers; D016014:Linear Models; D008959:Models, Neurological; D017933:Peripheral Nervous System / Q000502:physiology / Q000528:radiation effects; D011892:Rana catesbeiana; D012584:Sciatic Nerve / Q000502:physiology / Q000528:radiation effects*; D013997:Time Factors