Improvement of Wound Healing in Rabbit Skin by Low Level Polarized Laser Light

Abstract

Living cells require energy to perform biological processes and functions. Low level lasers stimulate the basic energy processes in the mitochondria and help the production of Adenosine Tri-Phosphate (ATP)–the primary biological cell energy source needed for such activities. Full-thickness, parallel wounds in four domesticated Albino rabbits were surgically induced. The control wounds were left without laser treatment, whereas other wounds received daily laser treatments using laser energy fluence of 5 J/cm2 for rabbit 1; 4.5 J/cm2 for rabbits 2 and 3; and 3.5 J/cm2 for rabbit 4. Various polarization directions of the 660 nm low level (5 mW) diode laser were used to heal the induced wounds. The laser beam’s plane of polarization with respect to the wound line played an important role in the healing results. The fastest healing was completed in 16 day-time using a parallel orientation of polarized laser beam, while the perpendicular orientation of the polarized laser beam healed at lower rate, and the 45o polarization orientation of the laser beam gave poorest healing results. Laser photons of the parallel orientation of polarization interact with a chromophore located within the tissue. Laser illumination of wound can raise the energy of the cells and generate new collagen and fibroblast tissues, because electron excitation and de-excitation are vital in the mitochondrial respiratory chain. Wounds illuminated with a polarized laser in a plane parallel (Lll) to the wound line built new cells which filled the wound at a very fast rate and in a more homogeneous manner. The transverse orientation (L┴) of the laser beam helped filling the cells but stacking them in the orthogonal direction which required longer healing time.