Effects of aging and reproductive history on bone parameters of common marmoset (Callithrix jacchus) mandibles

To understand effects of aging and reproductive history in the bones of common marmosets (Callithrix jacchus), mandibles from 79 males and 66 females were analyzed. Dry bone specimen was prepared from dissected mandible, and analyzed using a dual-energy x-ray absorptiometry (DXA) measurement system in terms of bone weight (BnW), bone area (AREA), bone mineral content (BMC), bone mineral density (BMD, ratio of BMC to AREA) and bone mineral ratio (BMR, ratio of BMC to BnW). The mandible bones became porous and thicker with age. The age-related changes in BnW, AREA and BMC showed inflection points at around 1.5-2 Y and 13-15 Y. The period before 1.5-2 Y corresponds to the growth phase, the period between the inflection points is the aging phase, followed by senescence after the second inflection point. BMD increased until 1.5-2 Y and gradually decreased thereafter in males, with a more dramatic decrease in females, probably because of pregnancy and lactation. BMR was stable after reaching its peak by 1 Y, unlike the other parameters we analyzed. BMD of parous female tended to be lower than that of nulliparous female aged 2-5 Y. This study identified some of the particular effects of aging and reproductive history on characteristics of mandible bones in common marmoset.