RESUMO
To determine how to eliminate species difference in animal bone experiment, bone mineral content (BMC) was measured using dual energy X-ray absorptiometry (DXA) on the femurs of laboratory mice (Mus musculus) and rats (Rattus norvegicus), and common marmosets (Callithrix jacchus). Measures were taken on femurs in situ, detached from the body, skinned and defleshed, or dried completely. When the BMC of the bone measured in the intact limb attached to the trunk was set at 100%, the actual BMC of the dry bone was 58.7 +/- 11.5% in mice and 103.2 +/- 3.2% in rats. Similarly, the bone area (Area) and bone mineral density (BMD) of the dried femur was significantly lower in the mouse femurs than intact limb. Thus, soft limb tissue such as skin and muscle modified the BMC, Area, and BMD only in mouse but not in those from rats or marmosets. The bone mineral ratio (BMR; BMC divided by dry bone weight) was nearest to the human bone value in the rat femurs, whereas the mouse femur BMR was the most different. The BMR was proved to be a practical index in evaluating bone characteristics in laboratory animals, but the mouse femur might not be suitable as an animal model for research into the aging of human bone.
Assuntos
Absorciometria de Fóton , Densidade Óssea/fisiologia , Callithrix/fisiologia , Animais , Fêmur/fisiologia , Humanos , Camundongos , RatosRESUMO
The body and major organ weights of A/J-Chr 11(SM) consomic mice were compared to those of the progenitor strains, A/J and SM/J. The weights of the body and organs, except for those of the brain and uterus, were significantly greater in A/J mice than in SM/J mice. However, those of consomic mice were highly variable. For example, the average body weight of consomic mice was significantly greater than that of SM/J mice and nearly equal to that of A/J mice. Chromosome 11 of SM/J mice induced various significant changes of the organ weights of A/J mice, especially those of the brain, lung, kidney, adrenal, and ovary, demonstrating the importance of this chromosome in determining the phenotypes.
Assuntos
Peso Corporal/genética , Cromossomos de Mamíferos , Camundongos Congênicos/genética , Camundongos Endogâmicos A/genética , Tamanho do Órgão/genética , Animais , Feminino , Camundongos , Camundongos Congênicos/crescimento & desenvolvimento , Camundongos Endogâmicos A/crescimento & desenvolvimento , FenótipoRESUMO
The aim of this study was to determine whether the thickness of the adrenocortical zone is associated with age in virgin and parous female DDD mice. The zona reticularis and zona glomerulosa of parous mice tended to be thicker than those of virgin mice at all ages. The zona fasciculata lactating parous mice was significantly thicker than that of virgin mice at 20 weeks of age (P<0.01). Age did not affect the thickness of the three outer adrenocortical zones in either group. However, in virgin mice, the X zone consisted of vacuolated and nonvacuolated cells at 5 weeks of age and only of vacuolated cells at 10 weeks of age; the number of vacuolated cells and the thickness of the zone decreased at 40 weeks of age. In contrast, parous mice of all ages lacked an X zone. The decrease in X zone thickness with age was most evident when expressed relative to organ weight. In conclusion, the thickness of the outer three adrenocortical zones is affected by endocrine changes associated with pregnancy and lactation but not by age. The thickness of the X zone is an index of growth and maturation in nulliparous female DDD mice less than one year of age.
