ABSTRACT
A study was conducted to investigate the mechanism of bone atrophy in various strains of inbred mice under the influence of tail-up suspension. Nine inbred strains of mice (NZB/N, NZW/N, AKR/N, Balb/C, C 57 BL, C 3 H/He, A/J, DBA, CBA/N) aged six weeks were used. Each strain was divided randomly into two groups, a suspension group (SG; n=5) and a control group (CG; n=5) . The suspension group were etherized and suspended with an elastic bandage. After one week, the tibiae were removed and their bone weights were measured using an electric balance (Metler; AE 240) . Their length was also measured with a vernier caliper. In all strains, body weight in the SG was significantly lower than that in the CG. From the bone weight and length in the CG, bone growth in the NZB/N, AKR/N, NZW/N and C3H/He strains was considered to be higher than in the other strains. On the other hand bone growth in the DBA, A/J, Balb/C, and CBA/N strains were lower than in the others. The absolute value of bone weight in the SG was significantly smaller than that in the CG in six strains (NZB/N, C 57 BL, A/J, NZW/N, C 3 H/He, Balb/C) . However in the DBA strain, the absolute value of bone weight in the SG was significantly higher than that in the CG.<BR>From the results of this investigation we suggest that the mechanism of normal bone growth is not the same as the mechanism of bone atrophy induced by tail-up suspension.