Table 2.

Bone microarchitecture and bone static and dynamic properties

	Young		Old
	CON	PTH	CON	PTH
Bone microarchitecture
n	7	10	7	9
Tb.Th, µm	21.2 ± 2.0	23.2 ± 2.4	19.6 ± 3.7	21.5 ± 3.0
Tb.N, /mm2	6.6 ± 1.1	7.5 ± 1.2e	3.6 ± 0.6	5.5 ± 1.1
Tb.Sp, µm	158.6 ± 29.4	149.8 ± 29.1	309.8 ± 52.5a	220.6 ± 41.3
Bone static properties: osteoblast activity
n	7	10	7	9
OS/BS, %	5.7 ± 1.1	5.1 ± 1.0	7.9 ± 1.6c	3.2 ± 0.7
Ob.S/BS, %	0.7 ± 0.5	0.8 ± 0.3	0.3 ± 0.2	0.4 ± 0.1
Bone static properties: osteoclast activity
n	8	11	9	9
Oc.S/BS, %	1.8 ± 0.3	2.5 ± 0.6d	1.4 ± 0.3	1.0 ± 0.3
Bone dynamic properties
n	8	8	8	8
MAR, µm/day	0.90 ± 0.30	1.18 ± 0.30	0.57 ± 0.05	0.55 ± 0.04
sLS/BS, %	1.44 ± 0.28	1.51 ± 0.13	0.78 ± 0.06	1.53 ± 0.38
dLS/BS, %	0.70 ± 0.19	1.41 ± 0.29b,d,f	0.34 ± 0.07	0.88 ± 0.22
MS/BS, %	1.42 ± 0.28	2.16 ± 0.32b	0.85 ± 0.18	1.65 ± 0.39
BFR/BS, µm3·µm−2·day−1	0.01 ± 0.00	0.02 ± 0.01	0.01 ± 0.00	0.02 ± 0.01

Values are means ± SE; the sample size n represents the number of rats per group. CON, control; PTH, parathyroid hormone; Tb.Th, trabecular thickness; Tb.N, trabecular number; Tb.Sp, trabecular separation; OS/BS, osteoid surface-to-bone surface ratio; Ob.S/BS, osteoblast surface-to-bone surface ratio; Oc.S/BS, osteoclast surface-to-bone surface ratio; MAR, mineral apposition rate, sLS/BS, single-labeled surface-to-bone surface ratio; dLS/BS, double-labeled surface-to-bone surface ratio; MS/BS, mineralizing surfaces-to-bone surface ratio; BFR/BS, bone formation rate-to-bone surface ratio.

^aP < 0.050 vs. Young CON and Young PTH,

^bP < 0.050 vs. Old CON,

^cP < 0.050 vs. Old PTH,

^dP < 0.100 vs. Old PTH,

^eP < 0.100 vs. Old CON,

^fP < 0.050 vs. Young CON.