Table 2.

Summary of the major targets and effects of growth factors in tendon repair.

Growth Factors		Main Roles	Effects	Ref.
bFGF			Promoted endogenous healing and barrier exogenous healing of tendon.	[106]
			Stimulated initial proliferation and subsequent tenogeneic differentiation of the BMSCs enhancing their collagen production.	[107]
		Bound to cell membrane receptors	Regulated proliferation of cells and promoted the expression of type III collagen.	[108]
TGF-β	TGF-β1	Key inducer of tenogenesis Mediated RhoA/ROCK signaling and mechanotransduction pathway	Induced transdifferentiation of narrow fibroblasts into tenocytes to enhance tendon repair.	[84]
			Promoted collagen synthesis, angiogenesis, and matrix protein regulation.	[109]
			Regulated tenocytes proliferation and differentiation and promoted collagen I production.	[106]
	TGF-β3	Key inducer of tenogenesis Paracrine pathway	Reflected key roles for regeneration compared with adult tendon.	[90]
			Promoted the expression of SCX, ELN, and TNC to reduce scar formation.	[95,96]
BMP	BMP-2		Activated downstream genes that induce stem cells into tenocytes.	[90]
			Induced the formation of collagen type I and resulted in a more native-like osteotendinous junction with better biomechanical properties.	[110]
	BMP-12	Triggered robust phosphorylation of Smad1/5/8 that conveyed by type I receptors ALK2/3/6	Increased the expression of the tendon marker scleraxis and tenomodulin at both mRNA and protein levels.	[111]
IGF-1		Activated PI3K/protein kinase B and ERK pathways Matrix production	Regulated collagen synthesis and tenocytes proliferation.	[82]
GDF	GDF-5		Induced ectopic bone and cartilage both in vivo and in vitro and caused the migration of host progenitors.	[90]
	GDF-6		Increased expression of tendon membrane proteins to induce tenogenic differentiation of the BMSCs.	[112]
	GDF-8		Induced tenogenic differentiation of the pluripotent stem cells.	[113]