Effect of TNF-α Inhibition on Bone Marrow-Derived Mesenchymal Stem Cells in Neurological Function Recovery after Spinal Cord Injury via the Wnt Signaling Pathway in a Rat Model

Abstract

Aim: The present study aimed to examine the effect of tumor necrosis factor-α (TNF-α) inhibition on bone marrow-derived mesenchymal stem cells (BMSCs) in neurological function recovery after spinal cord injury (SCI) via the Wnt signaling pathway in a rat model. Methods: The rat model of SCI was established using Allen's method. Seventy-two adult male Sprague Dawley (SD) rats were randomly assigned into 4 groups (18 rats in each group): the sham control group, saline control group, BMSCs group (injection with BMSCs at the injured site) and BMSCs + TNF-α group (injection with BMSCs under TNF-α treatment at the injured site). Immunochemistry was performed to characterize the culture media after TNF-α-induced differentiation. qRT-PCR and Western blotting analyses were performed to detect the mRNA and protein expression of β-catenin, Wnt3a, GSK-3β and Axin. The Basso Beattie Bresnahan (BBB) locomotor score, neurological deficit score (NDS), and balance beam test (BBT) score were used to assess neurological functional recovery of SCI rats. Results: In the BMSC group, numerous spherical cell clusters grew in suspension, and the cells were nestin-, NF200-and GFAP-positive. Compared with the sham control and BMSC groups, the β-catenin and Wnt3a mRNA and protein expression was increased, but the GSK-3β and Axin mRNA and protein expression was decreased in the BMSCs + TNF-α group. The SCI rats in the BMSCs + TNF-α group exhibited lower BBB scores, and higher NDSs and BBT scores compared to the BMSCs group. Conclusion: Our study provides evidence that TNF-α inhibition may weaken the ability of BMSCs in neurological functional recovery after SCI by activating the Wnt signaling pathway.