Table 2.
Comparison of skeletal phenotype in Cnr1, Cnr2 and Cnr1/2 double‐knockout (Cnr1/2−/−) compared to wild‐type mice
| Age | Genotype | BV/TV | Ct.Ar | Oc.N/BS | Ob.N/BS | MAR | MS/BS | BFR/BS |
|---|---|---|---|---|---|---|---|---|
| 3 months | CNR1−/− | 34. ±7.5 | 4. ±2.3ns | −54.0 ± 4.8* | −7.3 ± 10.9ns | 10.2 ± 6.6ns | −18.4 ± 4.5 | −9.1 ± 10.5ns |
| CNR2−/− | 55.5 ± 11.2 | −1.1 ± 2.1ns | −31.4 ± 6.3 | 4.7 ± 5.6ns | −21.3 ± 4.1* | −9.7 ± 3.8ns | −26.8 ± 5.4 | |
| CNR1/2−/− | 39.9 ± 3.4 | 2.8 ± 2.8ns | −22.0 ± 5.2 | −20.3 ± 4.6+ | 5.1 ± 3.5ns | −0.7 ± 1.5$ ns | 3.4 ± 3.9+ ns | |
| 12 months | CNR1−/− | −11.3 ± 6.2 | −4.0 ± 3.0ns | −91.9 ± 4.6* | −54.8 ± 10.7 | −55.9 ± 10.5 | −6.9 ± 6.7ns | −60.4 ± 8.1 |
| CNR2−/− | 7.6 ± 7.5ns | −4.7 ± 2.3ns | 0.0 ± 8.6ns | −34.4 ± 5.6 | −28.3 ± 6.1 | −21.5 ± 5.4 | −46.3 ± 6.4 | |
| CNR1/2−/− | 53.3 ± 12.5* | 6.4 ± 4.6ns | −18.4 ± 6.3ns | −33.7 ± 6.2 | 6.8 ± 5.9* ns | −30.4 ± 5.5 | −25.6 ± 7.3 |
Values are % change from wild‐type. BV/TV; trabecular bone volume; Ct.Ar; cortical area; Oc.N/BS, osteoclast number/bone surface; Ob.N/BS, osteoblast number/bone surface; MAR, mineral apposition rate; MS/BS, mineralizing surface/ bone surface; BFR/BS: bone formation rate/bone surface; ns, not significant from respective wild‐type control. Values are percentage difference from wild‐type and were obtained from six to eight animals (mean ± SEM). *P < 0.05 from all genotype groups, + P < 0.05 from Cnr2−/−, $ P < 0.05 from Cnr1−/−.