Promising effects of laser therapy and the natural latex protein on sciatic nerve crushed. Ultrastructural, sensory and functional study

Abstract

Treatment of lesions that affect peripheral nerves still presents a challenge, in this context the low‐level laser (LLL) and the protein of the natural latex (Hevea brasiliensis, F1) showed positive effects.The aim of this study was to analyze the effects of LLL associated with F1 in crush injuries of the sciatic nerve (15 kgf, 10') in rats. Six groups (n=24) of rats (♂, 250 g): C ‐ Control; E ‐ Exposed nerve without crushing; Le ‐ injured nerve without treatment; L ‐ injured nerve LLL irradiation (15 J/cm2, 780 nm); F1 ‐ injured nerve with application of F1 protein (0.1%); and LF1 ‐ injured nerve with the F1 protein and LLL irradiation. After 1, 7, 14, 28, 56 and 180 days of nerve injury of sensory and functional analyzes were performed: 1. mechanical allodynia (von Frey); 2. Pressure testing the paw (Forceps); 3. Grip strength test and 4. Motor function (SFI). After 3, 15, 57 and 181 days of nerve injury, the animals of each subgroup (n=6) submitted to intracardiac perfusion (2.5% glutaraldehyde in cacodylate buffer 0.1 M, pH 7.2), the sciatic nerve samples were collected and processed to ultrastructural analysis.The results revealed that the controlled nerve compression (15 kgf) was intense, thus spontaneous recovery was not enough to restore the normal characteristics of the sciatic nerve allowing to evaluate the effects of proposed therapies. The three treatment protocols proposed LLL, F1 and LLL+F1 revealed improvements in ultrastructural characteristics when compared with the untreated injured animals. It was noted correlation between these data and those functional sensory and motor, which also showed improvements with the treatments applied. All treatments applied resulted in improvements in the characteristics and tests evaluated, the time in all cases was an important factor in this recovery however in some functional tests there was an acceleration of improvements, and the animals that received F1 associated or not to LLL had generally the best results.Support or Funding InformationFunding: FAPESP 2014/07253‐4