NGF and VEGF expressions on crushed sciatic nerve treated with laser therapy and latex protein

Abstract

Lesions that affect peripheral nerves still is a challenge in medical sciences. In this context, previous studies employing low‐level laser therapy (LLLT) and natural latex protein (Hevea brasiliensis, F1) revealed promising results in nerve regeneration.The aim of this study was to analyze the effects of LLLT associated with F1 protein applied in sciatic nerve crush injury (15 kgf, 10 min.) in male rats. The animals (♂, 250 g) were allocated in 6 groups (n=5): C ‐ Control; E ‐ exposed nerve without injury; I ‐ injured nerve without treatment; L ‐ injured nerve treated with LLLT (15 J/cm2, 780 nm); F1 ‐ injured nerve treated with F1 application (0.1%); and L&F1 ‐ injured nerve treated with the LLLT and F1 protein. After 4 and 8 weeks of nerve injury the animals were euthanized by anesthetic overdose and cardiac perfusion (glutaraldehyde 2.5%, PBS 0.1, pH 7.4), the sciatic nerve samples were collected and processed. Quantitative morphological parameters (myelin and capillary density) and immunohistochemical reactions (peroxidase) for nerve growth factor (NGF) and vascular endothelium growth factor (VEGF) were performed and analyzed.After 4 weeks in the injured groups (I, L, F1 and L&F1) was observed a significant reduction in myelin density. After 8 weeks the treated groups showed improvements compared to the previous period, the F1 and L&F1 groups presented values similar to the non‐injured groups (C and E). Capillary density was significantly higher in the F1 and L&F1 groups after 8 weeks of nerve damage. NGF was present in the injured groups (I, L, F1, L&F1) after 4 weeks, the group I showed the highest and the F1 group revealed the lowest positive expressions. VEGF was present in all study groups, showing more intense expressions in the injured groups, especially after 4 weeks of lesion in the F1 and L&F1 groups. After 8 weeks all the groups reduced the marking intensity.It was concluded that the nerve injury crushing results in a reduction in myelin density. NGF is mainly expressed when nerve tissue is injured. The treatments were effective in the improvements of the morphological parameters analyzed. The F1 protein presented the best quantitative results and an increase in vascular density when applied alone or in association with LLLT. In addition, the less intense NGF expression after 4 weeks associated with morphological improvement in group F1 suggests the acceleration of sciatic nerve recovery.Support or Funding InformationFunding: FAPESP 2014/07253‐4This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.