Optimal concentration of mesenchymal stem cells for fracture healing in a rat model with long bone fracture

Table 1 Fracture healing scores according to the histological findings

Score	Histological findings
1	Fibrous tissue
2	Predominantly fibrous tissue with small amount of cartilage
3	Equal mixture of fibrous and cartilaginous tissue
4	Predominantly cartilage with small amount of fibrous tissue
5	Cartilage
6	Predominantly cartilage with small amount of immature bone
7	Equal mixture of cartilage and immature bone
8	Predominantly immature bone with small amount of cartilage
9	Union of fracture fragments by immature bone
10	Union of fracture fragments by mature bone

Table 2 Radiologic evaluation of the fractures using micro-computed tomography analysis

		Normal saline	2.5 × 106	5.0 × 106	10.0 × 106
Two weeks post-fracture	BV (μm3)	34.9 ± 3.1	37.3 ± 4.5	45.3 ± 2.9	45.7 ± 4.9
	Normal saline	-	0.878	0.048	0.040
	2.5 × 106	0.878	-	0.137	0.112
	5.0 × 106	0.048	0.137	-	0.999
	10.0 × 106	0.040	0.112	0.999	-
	PBV (TV/BV, %)	7.3 ± 0.8	9.0 ± 0.5	10.8 ± 1.2	11.0 ± 2.6
	Normal saline	-	0.517	0.079	0.067
	2.5 × 106	0.517	-	0.509	0.445
	5.0 × 106	0.079	0.509	-	0.999
	10.0 × 106	0.067	0.445	0.999	-
Six weeks post-fracture	BV (μm3)	71.3 ± 8.0	78.7 ± 8.8	101.4 ± 14.0	107.2 ± 6.9
	Normal saline	-	0.798	0.023	0.009
	2.5 × 106	0.798	-	0.083	0.030
	5.0 × 106	0.023	0.083	-	0.887
	10.0 × 106	0.009	0.030	0.887	-
	PBV (TV/BV, %)	13.4 ± 2.2	15.0 ± 3.1	20.5 ± 2.2	23.6 ± 3.3
	Normal saline	-	0.769	0.004	0.001
	2.5 × 106	0.769	-	0.026	0.003
	5.0 × 106	0.004	0.026	-	0.425
	10.0 × 106	0.001	0.003	0.425	-

CT: Computed tomography; BV: Bone volume; PBV: Percentage bone volume; TV: Tissue volume.