Effect of laser irradiation on myelo- and angioarchitecture of the distal nerve segment during reparative processes
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1
IVANO-FRANKIVSK NATIONAL MEDICAL UNIVERSITY, IVANO-FRANKIVSK, UKRAINE
2
I. HORBACHEVSKY TERNOPIL NATIONAL MEDICAL UNIVERSITY, TERNOPIL, UKRAINE
Publication date: 2026-04-30
Wiadomości Lekarskie 2026;(4):720-727
KEYWORDS
ABSTRACT
Aim: To investigate the effect of laser irradiation on myelinated fibers and blood vessels in the distal segment of the sciatic nerve after its transection and
surgical repair.
Materials and Methods: The study was conducted on 39 male rabbits. The left sciatic nerve was transected at the mid-thigh level and repaired with epineurial
sutures. The experimental animals were irradiated with a helium-neon laser with a light energy density of 2.5 mW/cm². The exposure duration was 5 minutes;
the treatment course comprised 15 sessions; the total delivered energy was 90 J. At each time point, three animals from each group were used. All procedures
involving animals were conducted in accordance with bioethical guidelines. Myelinated fibers were stained with the Kulchitsky-Pal stain, and intraneural
microvessels were visualized by injection with a chloroform/ether solution of Prussian blue dye.
Results: On days 7 and 14 of the experiment, typical Wallerian degeneration developed in the distal segment of the nerve. Myelinated fibers degenerated
more rapidly in irradiated animals. Three stages of Wallerian degeneration, each with distinct characteristics, were identified. On day 7, axonal fragmentation
and globular fragmentation of myelin (myelin ovoids) predominated, whereas by day 15, resorption of degenerative products prevailed. From day 30 onward,
reinnervation of the distal nerve segment began, with laser irradiation significantly enhancing the process. It accelerated angiogenesis, dilated and increased
the number of blood vessels, and increased their total cross-sectional area, indicating improved blood supply.
Conclusions: Helium-neon laser irradiation accelerates and enhances all processes occurring in the distal segment of the nerve after neurotomy: Wallerian
degeneration and reinnervation, axonal growth, myelination, and maturation; restoration of myeloarchitecture; revascularization and blood supply; and
reconstruction of the nerve’s angioarchitecture. Distal to the injury, reparative angiogenesis precedes the regeneration of myelinated fibers.