Table 2.
Experimental conditions for in vivo hindlimb unloading models
| Animal | Age and gender | Tail-suspension durations | Brief summary | Ref. |
|---|---|---|---|---|
| Mice | 6 weeks, male | 3 days or 7 days | Increased Sost mRNA in unloading tibia after 3 days treatment; no significant sclerostin-positive osteocytes detected in unloading groups. | 25 |
| Mice | 12 weeks, female | 21 days | Hindlimb bone mineral density decreased 9.2% ± 1.0% in HLU of control group. | 28 |
| Mice | 17–21 weeks, female | 14 days | Myonuclear number was not altered during either the suspension or the reloading period in soleus muscle fibers from vehicle-treated or satellite cell-depleted animals. | 36 |
| Mice | 5 months, n/a | 10 days | During the unloading period, soleus muscle fiber cross section decreased by 38%. | 37 |
| Mice | 14 weeks, male | 28 days | 28 days of HLU-induced serious damages in microstructure and mechanical property of the tibia in WT mice. | 123 |
| Mice | 3 months, female | 21 days | HLU-induced significant bone loss, as demonstrated by significant decreases in BV/TV, Tb.N, and Ct.Th and an increase in Tb.Sp. | 169 |
| Mice | 4 months, n/a | 3 or 14 days | The soleus muscle/body weight ratio decreased by 41% in WT-HLU 14 days, whereas cross‐sectional area fell by 29% in WT‐HLU 14 days. | 38 |
| Mice | 8 weeks, male | 21 days | The mRNA expression of Lcn2 significantly increased in the bones of the suspended hindlimbs with respect to those of the hindlimbs of mice maintained under normal conditions. | 214 |
| Rats | 6/8 months, female | 28 days | After a 28-day protocol, disuse group reduced BFR (−92%), a suppression only slightly curbed when disuse was interrupted by 10 min of weight bearing (−61%). In contrast, disuse interrupted by 10 min per day of low-level mechanical intervention normalized BFR to values seen in age-matched controls. | 26 |
| Rats | 9/29 months, male | 14 days | Decreases in body weight were observed between the adult (12.2% loss) and old (14.6% loss) rats through 14 days of HLU. Adult rats lost a greater percentage of their hindlimb muscle mass after 2 weeks of HUL compared with the old rats. | 215 |
F frequency for loading, Ref. references, n/a not available, BV/TV bone volume fraction, Tb.N trabecular number, Ct.Th cortical thickness, Tb.Sp trabecular separation, BFR bone-formation rate