[Effects of hindlimb unloading on bone histomorphometry and bone mass in rats].
OBJECTIVE
To study the effects of hindlimb unloading on bone histomorphometry, bone local growth factor, bone biomechanical properties and bone contents in rats.


METHODS
Male SD rats were arranged into free active control group (CON) and tail-suspended group (TS) with 9 rats in each group. The experiment lasted for 3 weeks. Bone histomorphometry, bone local growth factor, biomechanical properties and bone contents were measured before and after tail suspension.


RESULTS
Structure of the trabecular bone was disorganized. Compared with CON, trabecular bone volume (% Tb. Ar), mean trabecular plate thickness (Tb. Th), osteoblast surface (Ob. S) were significantly reduced in TS. The eroded surface (Oc. N/BS) tended to be higher, though not significant at this stage of tail suspension; alkaline phosphatase (ALP) activity in the tibia were significantly reduced, but NO content in the femoral trunk was significantly decreased; bone biomechanical properties, bone mineral content (BMC), bone density (BD) and bone collagen density (BCD) in the femur were significantly reduced.


CONCLUSIONS
Hindlimb unloading may lead to regression of bone microstructure, change of bone local growth factor content, reduction of bone biomechanical properties and bone content.
Institute of Space Medico-Engineering, Beijing, China.
Da-wei
DW
Huang
Yu-min
YM
Wan
Zhi-zhen
ZZ
Shi
Zeng-ming
ZM
Huang
Ying-hui
YH
Li
Yong-jie
YJ
Ma
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D015519:Bone Density; D016723:Bone Remodeling; D001842:Bone and Bones / Q000033:anatomy & histology* / Q000378:metabolism*; D003094:Collagen / Q000378:metabolism; D005269:Femur / Q000033:anatomy & histology / Q000378:metabolism; D019417:Hindlimb Suspension; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D010006:Osteoblasts / Q000166:cytology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013977:Tibia / Q000033:anatomy & histology / Q000378:metabolism
D009569:Nitric Oxide; D003094:Collagen; D000469:Alkaline Phosphatase