Table 1.

Trabecular morphology of the femoral metaphysis and cortical morphology of the femoral mid-diaphysis at baseline and the relative change in morphology between baseline (16 wk) and time of death (34 wk) in control mice and those subject to hindlimb unloading once (1x-HLU), twice (2x-HLU), or three times (3x-HLU)

	Average Baseline	Change Between Baseline and Death, %
	Value	Control	1x-HLU	2x-HLU	3x-HLU
Metaphysis
Body Mass, g	28 ± 0.53	15 ± 4.5*	14 ± 5.1*	9.8 ± 5.5*	11 ± 4.8*
BV/TV, %	8.6 ± 0.35	−36 ± 6.4*	−41 ± 15*	−47 ± 9.4*,a	−46 ± 9.0*,a
Tb.N, 1/mm	4.9 ± 0.08	−20 ± 5.3*	−20 ± 5.3*	−24 ± 4.0*	−20 ± 4.6*
Tb.Th, μm	41 ± 0.73	10 ± 6.1*	8.8 ± 5.1*	4.1 ± 3.6*a	3.8 ± 4.6*a
Tb.Sp, mm	0.20 ± 0.003	26 ± 8.8*	24 ± 9.0*	31 ± 6.5*	25 ± 7.5*
Conn.D, 1/mm3	35 ± 4.2	77 ± 17*	77 ± 21*	76 ± 18*	78 ± 17*
Diaphysis
Ct.Ar, mm2	0.82 ± 0.01	2.1 ± 5.1	4.0 ± 5.5*	0.49 ± 5.4	−2.8 ± 5.1a,b
Ct.Th, μm	180 ± 2.8	−3.4 ± 6.3	0.95 ± 4.8	−3.2 ± 6.4	−4.3 ± 6.3
Ma.Ar, mm2	1.1 ± 0.02	4.5 ± 5.0*	3.1 ± 3.9*	3.7 ± 4.3*	1.6 ± 3.5
Tt.Ar, mm2	1.9 ± 0.03	3.3 ± 3.1*	3.7 ± 3.6*	2.1 ± 2.4*	−0.23 ± 1.6a,b
Ct.Ip, mm4	0.42 ± 0.01	5.0 ± 8.1*	7.1 ± 8.8*	−3.0 ± 6.0b	−1.1 ± 5.5b
Ct.TMD, mgHa/ccm	1100 ± 12	1.2 ± 1.9*	4.2 ± 1.8*	0.18 ± 2.6b	1.0 ± 2.7b
ICP, %	98 ± 0.74	0.44 ± 1.1	−0.21 ± 0.98	−0.11 ± 0.55	−0.04 ± 0.63
BSI, mm4 mgHA/ccm	160 ± 21	13 ± 12*	17 ± 7*	2.8 ± 6.7a,b	1.1 ± 13a,b

Data are shown as means ± SD. Letters denote significant differences (P < 0.05) between groups.

^*Significantly different from baseline, P < 0.05. ^aAny group significantly different from control. ^b2x- or 3x-HLU significantly different from 1x-HLU. ^c3x-HLU different from 2x-HLU. BV/TV, trabecular bone volume fraction; Tb.Th, trabecular thickness; Tb.N, trabecular number; Tb.Sp, trabecular separation; Conn.D, connectivity density; Ct.Ar, cortical bone area; Ct.Th, cortical bone thickness; Ma.Ar, marrow area; Tt.Ar, total area; Ct.TMD, cortical tissue mineral density; Ct.Ip, cortical polar moment of inertia; ICP, intracortical porosity; BSI, cortical bending strength index.