Parathyroid hormone PTH(1–34) increases the volume, mineral content, and mechanical properties of regenerated mineralizing tissue after distraction osteogenesis in rabbits

Figures & data

Figure 1. Radiograph taken during the consolidation period on day 28 (PTH group) showing both periosteal and endosteal regenerate callus.

Figure 2. Longitudinal sections of the bone specimens made after the mechanical testing procedure: A. PTH; B. control. Bar = 10 mm.

Table 1. Animal body weight characteristics

	Mean (SD) [range]			p-value
Body weight (g)	PTH (n = 19)	Vehicle + PTH (n = 17)	Control (n = 15)	ANOVA	PTH vs. Control	Vehicle+PTH vs. Control	PTH vs. Vehicle+PTH
Initial	3.94 (28) [3,500–4,450]	3,900 (304) [3,400–4,500]	4,063 (275) [3,500–4,600]	0.3	0.2	0.1	0.7
Final	3.55 (26) [3,150–3,950]	3,485 (295) [2,900–3,950]	3,787 (308) [3,200–4,300]	0.01	0.02	0.005	0.5

Table 2. Total regenerate callus volume and external callus dimension properties of the regenerated callus

	Mean (SD)			p-value
	PTH (n = 19)	Vehicle + PTH (n = 17)	Control (n = 15)	^a ANOVA ^b Kruskal-Wallis	PTH vs. Control	Vehicle+PTH vs. Control	PTH vs. vehicle+PTH
Volume (mm^3)
Mid-diaphyseal
sample (40 mm)	4,030 (220)	4,129 (296)	2,536 (73)	< 0.001 ^b	< 0.001	< 0.001	0.8
sample left (40 mm)	1,621 (27)	1,653 (37)	1,673 (31)	0.5 ^a	0.3	0.7	0.5
Regenerated callus	2,408 (211)	2,557 (299)	862 (56)	< 0.001 ^b	< 0.001	< 0.001	0.9
Callus dimensions (mm)
Anterior-posterior (AP)	13.2 (0.5)	12.7 (0.6)	10.4 (0.3)	< 0.001 ^a	< 0.001	0.002	0.4
Medial-lateral (ML)	13.4 (0.3)	13.3 (0.3)	11.1 (0.2)	< 0.001 ^a	< 0.001	< 0.001	0.9

Table 3. Bone mineral content (BMC) and bone mineral density (BMD) of the regenerated callus, and BMD of the contralateral intact tibia

	Mean (SD)			p-value
	PTH (n = 19)	Vehicle + PTH (n = 17)	Control (n = 15)	^a ANOVA ^b Kruskal-Wallis	PTH vs. Control	Vehicle+PTH vs. Control	PTH vs. Vehicle+PTH
Total ROI
BMC (g)	0.91 (0.12)	0.9 (0.21)	0.59 (0.84)	< 0.001 ^a	< 0.001	< 0.001	0.7
BMD (mg/cm^2)	400 (40)	390 (70)	311 (40)	< 0.001 ^b	< 0.001	< 0.001	0.6
De novo ROI
BMC (g)	0.33 (0.05)	0.33 (0.09)	0.21 (0.04)	< 0.001 ^a	< 0.001	< 0.001	0.7
BMD (mg/cm^2)	370 (40)	360 (80)	270 (40)	< 0.001 ^b	< 0.001	< 0.001	0.6
Contralateral central ROI
BMD (mg/cm^2)	314 (20)	300 (20)	290 (20)	0.01 ^a	0.004	0.3	0.05

Table 4. Results of the three-point bending test for the distracted tibia and the contralateral intact tibia. The analysis was performed using data adjusted to the final body weight of the animal (see the text for detail). Selected data are shown in Figure 3

	Mean (SD)			p-value, (95% CI for differences)
	PTH (n = 19)	Vehicle + PTH (n = 17)	Control (n = 15)	ANOVA	PTH vs. Control	Vehicle + PTH vs. Control	PTH vs. Vehicle + PTH
Distracted tibia
Fmax (N)	344 (29)	338 (40)	260 (27)	< 0.001	0.001 (-228 to -60)	0.001 (66 to 242)	0.9 (-67 to 88)
Wabs (mJ)	454 (112)	374 (112)	227 (101)	0.02	0.01 (-489 to -100)	0.02 (31 to 437)	0.5 (-240 – 119)
Stiffness (N/mm)	283 (71)	269 (80)	250 (34)	0.2	0.3 (-141 to 19)	0.2 (-31 to 133)	0.8 (-83 to 63)
Intact contralateral tibia
Fmax (N)	491 (14)	453 (14)	449 (14)	0.005	0.004 (-100 to -20)	0.07 (-15 to 69)	0.2 (-70 to 3)

Figure 3. Box-and-whisker plots showing the results of the three-point bending test of the distracted tibia.