The effect of high-intensity versus photobiomodulation therapy (PBM) on the regeneration of the sciatic nerve following crush injury: an animal study

Abstract

The purpose of this research was to evaluate the therapeutics effects of photobiomodulation and high intensity laser therapy after a sciatic nerve crush injury. Following the crush injuries of sciatic nerve, 33 rats were randomly divided into three groups. The injured sciatic nerves of the rats in the control group were left to heal spontaneously, whereas HILT (120 J/session and 1064 nm) and photobiomodulation therapy (PBM) (2.4 J/session and 650 nm) were started immediately after surgery and performed once every 3 days (10 session in total) during the postoperative period. Electrophysiological evaluations were conducted before surgery and at the end of the healing period. The Sciatic Functional Index (SFI) was assessed before surgery and at the end of the healing period. The ratio of the inner axonal diameter to the total outer axonal diameter (g-ratio) and schwann cells per square micrometer were histomorphometrically evaluated. At the end of the 30-day healing period, significantly better SFI scores were noted in the HILT group compared with PBM (p=0.002) and control (p < 0.001) groups. HILT exhibited positive effects on latency and duration values when compared PBM (p=0.002, p=0.014) and control (p=0.003, p < 0.001) groups. The number of nerves with an optimum g-ratio was higher in the HILT group which indicates a better rate of myelination. Functional, histomorphometric, and electrophysiological investigations of the present study revealed that HILT seems to be a superior treatment modality for peripheral nerve regeneration.