Bone marrow mesenchymal stem cells in treatment of peripheral nerve injury

Table 1 Mechanisms of bone marrow mesenchymal stem cell therapy for peripheral nerve injury

Mechanism	Key processes/factors	Description	Ref.
Differentiation into nerve cells	SCs, neurons	BMSCs differentiate into various nerve cells, including neurons, astrocytes, and Schwann cell-like cells, both in vitro and in vivo	[27-34]
Improvement of nerve regeneration microenvironment	Neurotrophic factors, ECM molecules, adhesion molecules, paracrine effects	BMSCs secrete neurotrophic factors, regulate ECM components, secrete adhesion molecules, and exert paracrine effects, creating a suitable microenvironment for nerve regeneration and functional recovery	[5,14,35-39,41-43,48,49,51-53]
Promotion of neovascularization	VEGF, endothelial cells	BMSCs secrete VEGF and differentiate into endothelial cells, participating in the process of vascular development and promoting the formation of new blood vessels	[15,54-56]
Enhancement of myelination and axon regeneration	Myelinating cells, myelin proteins, neurotrophic factors, Schwann cells	BMSCs promote myelination and axon regeneration by differentiating into myelinating cells or Schwann cells, secreting neurotrophic factors and regulating the expression of myelination-related genes, thereby improving nerve function	[5,47,57,63,64,66-69]
Immune modulation	Cytokine regulation, macrophage polarization, extracellular vesicles, soluble factors	BMSCs control inflammation, prevent autoimmune reactions, and create a favorable environment for nerve repair and regeneration by regulating the expression of various cytokines, modulating macrophage polarization, releasing EVs, and secreting soluble factors	[70-77]

SCs: Schwann cells; BMSC: Bone marrow mesenchymal stem cell; ECM: Extracellular matrix; VEGF: Vascular endothelial growth factor; EVs: Extracellular vesicles.