The effect of laser radiation on glial fibrillary acidic protein and allograft inflammatory factor-1 expression in severed and surgically repaired sciatic nerve.

Objective: Determine the effect of different spectrum laser radiations on the expression of Glial Fibrillary Acidic Protein (GFAP) and allograft inflammatory factor-1 (Iba-1) in the sciatic nerve during regeneration.

Methods: The experiment was performed on 60 lab Wistar rats weighing 200-250 g. The left sciatic nerve was severed and subsequent end-to-end epineural suturing was performed 10, 20, 30, and 45 minutes after neurotomy. Western blot and immunohistochemistry analyses were performed by means of polyclonal anti-GFAP antibodies (Thermo Fisher Scientific, USA) and anti-Iba-1 antibodies (Invitrogen, USA) 90 days after nerve repair.

Results: The use of green and blue spectrum laser radiation significantly increased GFAP protein expression regardless of the time when surgical nerve repair was performed after injury. The expression of Iba-1 and tubulin after blue spectrum laser radiation with a wavelength of 470 nm was significantly higher than the control values by 5.1-11.0 times. An increase in the expression of Iba-1 and tubulin was noted when a green spectrum laser with a wavelength of 560 nm was utilized and nerve suturing was performed 10 and 20 minutes after nerve injury. The green spectrum laser with a wavelength of 520 nm had no significant effect on the expression of Iba-1 and tubulin. Morphologically, the highest proliferative reaction of glia was recorded when using a blue spectrum laser.

Conclusions: Laser radiation with blue (470 nm) and green (560 nm) spectra, promoted the activation of GFAP-positive Schwann cells and nerve regeneration. Activation of microglia is a necessary component of nerve regeneration and the content of Iba-1 represented the efficiency of regeneration.