EFFECT OF INFRARED LOW-POWER LASER IRRADIATION ON REGENERATION OF MYELINATED AXONS

The purpose of the present study was to examine the regeneration of my elinated axons under the effect of laser irradiation at various wavele ngths and energy densities. Laser irradiation at 890 nm with an energy dose of 0.33 J cm(-2) as well as He-Ne laser irradiation failed to ch ange the number of regenerating myelinated axons in distal nerve stump s on the 30th day after cutting the nerve. An increase of dose deliver ed to the skin to 9.33 J cm(-2) resulted in a 49% decrease in the numb er of myelinated axons. A 24% suppression of nerve regeneration was al so registered using 1220 nm wavelength laser (dose 0.98 J cm(-2)). Thi s phenomenon is likely to be attributed to the stimulating effect of l aser irradiation of the near-infra-red range on proliferation of fibro blasts and scar formation. 1220 nm of 7.2 J cm(-2) dose effected neith er the growth nor the myelinization of axons in distal nerve stumps on the 20th day following nerve damage.