ω-3 Polyunsaturated Fatty Acids Facilitate the Repair of Peripheral Nerve Defects with Chemically Extracted Acellular Allograft in Rats

Abstract

Acellular allograft (ACA) improves the repair and reconstruction of long peripheral nerve defects. ω-3 Polyunsaturated fatty acids (PUFAs) carry a neuroprotective potential, and their effects on ACA bridging were elucidated. Thirty rats with long gap sciatic nerve defects (15 mm long) were randomly divided into three groups ($n=10$): ACA, ACA + PUFAs, and autograft (AU). Limb condition, wet weight of tibialis anterior muscle (TAM), nerve electrophysiology, S-100, horseradish peroxidase (HRP), and percentage of splenic CD4+ and CD8 + T-lymphocytes were evaluated for 12 weeks after the operation. Rats in the AU and ACA + PUFA groups showed superior condition in affected limbs compared to the ACA group. At 12 wk after surgery, the wet weight of TAM in the ACA + PUFA group was higher than that in the ACA group ($0.4519\pm 0.1185$vs.$0.3049\pm 0.1272$;$P<0.01$) but lower than that in the AU group ($0.4519\pm 0.1185$,$0.5628\pm 0.0092$;$P<0.05$). In all the three groups, sole irritation elicited withdrawal reflex, and S-100 staining was detected in plantar skin. Moreover, horseradish peroxidase staining was overt in both the ventral horn and dorsal root ganglion of the spinal cord. Nerve conduction velocity (m/s), amplitude of action potential (mV), or somatosensory evoked potentials in ACA + PUFAs ($28.81\pm 1.04$,$2.20\pm 0.27$,$6.98\pm 0.29$) were significantly different from that in the AU ($35.71\pm 1.28$,$1.81\pm 0.19$,$8.15\pm 0.52$;$P<0.05$) and ACA ($20.03\pm 1.94$,$2.95\pm 0.36$,$5.22\pm 0.53$;$P<0.01$) groups. The percentages of splenic CD4+ and CD8+ cells were similar among the three groups. Omega-3 PUFAs improve the bridging effect of ACA on long gap peripheral nerve defects by promoting neuroprotection without arousing an immune response.