TGF-β1 Improves Nerve Regeneration and Functional Recovery After Sciatic Nerve Injury by Alleviating Inflammation

Background: Peripheral nerves have a certain regenerative ability, but their repair and regeneration after injury is a complex process, usually involving a large number of genes and proteins. In a previous study, we analyzed the gene expression profile in rats after sciatic nerve injury and found significant changes in transforming growth factor-beta 1 (TGF-β1) expression, suggesting that TGF-β1 may be involved in the process of nerve regeneration after injury. Methods: In this study, we first detected the time-course expression and localization of TGF-β1 in dorsal root ganglion (DRG) tissues in a rat sciatic nerve transection model via RT-qPCR. Secondly, we investigated the bioactive roles of TGF-β1 in primary cultured DRG neuron cells through a CCK8 assay, TUNEL assay, and immunofluorescence staining. Thirdly, we explored the neuroprotective roles of TGF-β1 in an in vivo model of sciatic nerve regeneration through morphological observation, behavioral, and electrophysiological tests, and a molecular biological measure. Results: We found that TGF-β1 expression was increased after injury and mainly located in the cytoplasm and nuclei of neuron cells in the DRG. TGF-β1 may regulate the viability, apoptosis, and neurite outgrowth of primary DRG neuron cells. In our in vivo model of sciatic nerve regeneration, TGF-β1 improved nerve regeneration and neuronal function recovery after sciatic nerve injury, alleviated the inflammatory response, and relieved neuropathic pain via the TGF-β1/smad2 pathway. Conclusions: This study provides an experimental and theoretical basis for using TGF-β1 as a neuroprotective agent after peripheral nerve injury in clinical practice in the future.