Histomorphometry in the quantitative analysis of osteoporosis in rat models

Objective In order to clearly clarify the relationships between bone architecture and osteoporosis,namely,quantitatively evaluate the values of bone quality,a comparative analysis of samples of osteoporosis models was performed by bone tissue histomorphometry and 3-D reconstruction of micro-CT images,and to explore the values of those two techniques.Methods Thirty healthy adult female SpraqueDawley rats were included in this study.The rats were randomly divided into sham group,ovariectomized group and ovariectomy + alendronate sodium group(n = 10,each).The rats were sacrificed at 100 days after drug administration.The bone mass density(BMD) of the whole femur was measured and histological sections of the undecalcified bone tissue of the distal end of femur were prepared for morphometric observation.A region of 2 mm 3 bone tissue beneath the epiphyseal plate of the distal end of femur was used for morphometric measurement to make 3-D reconstruction of micro-CT images(eXplore Locus SP,GE,USA) using software Micview V2.1.2.Results The bone mass density in the ovariectomized gourp was(19.16 ± 2.97) %,significantly decreased than that(53.00 ± 3.20) % in the sham group [(53.00 ± 3.20) % ],(P 0.001),and was(40.40 ± 3.07) after the alendronate sodium treatment,significantly improved than that of the ovariectomized gourp(P 0.001).There were significant differences in the values of tetracycline labeling rate,osteoid surface density,average osteoid formation surface thickness,mineralization apposition rate and bone mineralization delay time between the sham group and ovariectomied groups,and between the ovariectomized and alendronate sodium treatment groups(P 0.05).The 3-D reconstruction of micro-CT observation showed that the bone trabecular volume ratio(BV/TV) and bone surface/bone volume ratio,BS/BV) were similar to those obtained by histomorphometry,except that the absolute values were smaller.The 3-D reconstruction of micro-CT images also showed that except the bone trabecular thickness(Tb.Th),there were significant changes in the bone trabecular number(Tb.N) and bone trabecular separation(Tb.Sp).Conclusions Bone architecture and bone mass indicators can be objectively,qualitively and quantitatively evaluated by both bone histomorphometry and 3-D reconstruction of micro-CT images.Bone histomorphometry can be used to study the static and dynamic bone metabolic process,and well depict the regularity and characteristics of bone remodeling.