HeNe laser irradiation delivered transcutaneously: Its effect on the sciatic nerve of rats

Abstract

For our study of the effect of low energy laser irradiation (LELI) on living tissue we used HeNe laser on rats. The exponential absorption was reaffirmed in the living tissues overlying the sciatic nerve. An optimal range of energy between 3.5 and 7 J--associated with energy concentration of 4-10 J/cm2 delivered transcutaneously--was found to cause a significant increase in action potential in the sciatic nerve. The effect lasted for more than 8 months after the irradiation session.

Electrophysiological Effects of Single Point Transcutaneous 650 and 808 nm Laser Irradiation of Rat Sciatic Nerve: A Study of Relevance for Low-Level Laser Therapy and Laser Acupuncture

“…In contrast, the visible wavelength 650 nm (InGaAlP) 35 mW, cw in our study, for 30 sec (1.1 J) or 120 sec (13.5 J), caused no change in CAP, although the total energy delivered in 2 min is greater than that reported by Rochkind and Nissan over the same time. 22,23 The difference between our study and theirs may be the result of the longer duration of LI or different wavelength characteristics, such as greater coherence with HeNe resulting in greater photon penetration, 24 or other laser parameters as yet undefined for InGaAlP diode. The increased amplitude with our IR 808 nm LI, could, in contrast, be the result of the higher total energy delivered of 54 J.…”

“…We therefore propose that conduction block would occur a priori in these nerve endings as well as in the underlying nerve trunk, which receives only 3-10% of transmitted photons. 23 This clearly demonstrates the relevance of multiple point LI for pain relief as demonstrated in clinical trials of, for example, neck pain, 37 knee osteoarthritis, 38 and lateral epicondylitis. 39 Our findings are also relevant for the treatment of neuralgias including carpal tunnel syndrome, for which LLLT reduces symptoms when applied at several points over the wrist.…”

“…These studies applied LI continuously for 30 min. 22,23 The increase in CAP amplitudes occurred 7 min after delivery of *7 J, which gradually returned to baseline and then decreased to below normal at 30 min. In contrast, the visible wavelength 650 nm (InGaAlP) 35 mW, cw in our study, for 30 sec (1.1 J) or 120 sec (13.5 J), caused no change in CAP, although the total energy delivered in 2 min is greater than that reported by Rochkind and Nissan over the same time.…”

Infrared Laser Therapy for Ischemic Stroke: A New Treatment Strategy

“…A large and growing body of scientific literature is available documenting the photobiostimulation effects of infrared laser therapy both in vitro and in vivo. [5][6][7][8][9] The biological effects of infrared laser therapy are wavelength-specific and are not attributable to thermal effects. 10 -12 Energy in this region of the electromagnetic spectrum is nonionizing and, therefore, poses none of the hazards associated with UV light.…”

“…7,8,15 Lapchak et al, 16 Oron et al, 17 and DeTaboada et al 18 have shown in 2 different animal models a positive impact of infrared laser therapy on the experimental, ischemic stroke treatment outcomes in New Zealand rabbits (rabbit small clot embolic stroke model [RSCEM]) and Sprague-Dawley rats (permanent middle cerebral artery occlusion). Lapchak has shown that laser treatment at 6 hours poststroke onset in RSCEM improved behavioral performance and produced a durable effect that was measurable 21 days after embolization.…”