Acellular nerve graft enriched with mesenchymal stem cells in the transfer of the phrenic nerve to the musculocutaneous nerve in a C5-C6 brachial plexus avulsion in a rat model.

INTRODUCTION: Phrenic nerve transfer has been shown to achieve good nerve regeneration in brachial plexus avulsion. Acellular nerve allografts (ANAs) showed inferior results to autografts, which is why its use with mesenchymal stem cells (MSCs) is currently being studied. The aim is to study the effect of BM-MSCs associated with ANAs in a rat model of phrenic nerve transfer to the musculocutaneous nerve in a C5-C6 avulsion. MATERIAL AND METHODS: 42 Wistar-Lewis rats underwent a C5-C6 lesion in the right forelimb by excising a 3 mm segment from both roots, followed by a phrenic nerve transfer to the musculocutaneous nerve associated with the interposition of a three types of nerve graft (randomly distributed): control (autograft) group (n = 12), ANAs group (n = 12), and ANAs + BM-MSCs group (n = 18) After 12 weeks, amplitude and latency of the NAP and the compound motor action potential (CMAP) were measured. Biceps muscles were studied by histological analysis and nerve grafts by electron microscopy and fluorescence analysis. RESULTS: Statistically significant reductions were found in latency of the CMAP between groups control (2.48 ± 0.47 ms) and experimental (ANAs: 4.38 ± 0.78 ms, ANAs + BM-MSCs: 4.08 ± 0.85 ms) and increases in the amplitude of the CMAP between groups control (0.04388 ± 0.02 V) and ANAs + BM-MSCs (0.02275 ± 0.02 V), as well as in the thickness of the myelin sheath between groups control (0.81 ± 0.07 µm) and experimental (ANAs: 0.72 ± 0.08 µm, ANAs + BM-MSCs: 0.72 ± 0.07 µm) and in the area of the myelin sheath between groups control (13.09 ± 2.67 µm2 ) and ANAs (10.01 ± 2.97 µm2 ) (p < .05). No statistically significant differences have been found between groups ANAs and ANAs + BM-MSCs. CONCLUSIONS: This study presents a model for the study of lesions of the upper trunk and validates the autologous graft as the gold standard.

Growth factor expression after lesion creation in the avascular zone of the meniscus: a quantitative PCR study in rabbits.

PURPOSE: To define the variations in the expression of 5 growth factor genes in meniscal tissue after a lesion is created in the avascular zone of the medial meniscus of the rabbit. METHODS: A longitudinal lesion was created in the avascular zone of the anterior horn of the medial meniscus in 42 rabbits. Six animals were killed at 0, 1, 3, 7, 14, 21, and 120 days after lesion creation. Meniscal tissue from the avascular and vascular zones was harvested. A quantitative polymerase chain reaction analysis was performed to evaluate the expression levels of 5 different growth factors: vascular endothelial growth factor A (VEGF-A), insulin-like growth factor 1 (IGF-1), transforming growth factor ß1 (TGF-ß1), platelet-derived growth factor ß (PDGF-ß), and interleukin 1ß. RESULTS: The basal expression levels of all the growth factors studied were similar in the avascular and vascular zones. There was an increase in VEGF-A expression in the avascular zone on the 14th day, an increase in IGF-1 expression in the vascular zone on the 14th day, a decrease in PDGF-ß expression in both zones in the first week, an increase in interleukin 1ß expression in both zones on the first day, and a decrease in TGF-ß1 expression in the vascular zone in the first week. At 120 days, the expression levels of all 5 growth factors returned to basal levels. CONCLUSIONS: There are significant variations in the expression of the growth factors studied during the first weeks after meniscal lesion creation. The preinjury expression levels are similar in the avascular and vascular zones and are not significantly different from the basal levels 4 months after injury. CLINICAL RELEVANCE: This study identifies potential therapeutic molecular targets (VEGF-A, IGF-1, TGF-ß1, and PDGF-ß) that can be used in the treatment of meniscal tears.