Differences in vertebral, tibial, and iliac cancellous bone metabolism in ovariectomized rats.

Bone histomorphometry is usually performed on the iliac bone in humans and the tibia or vertebrae in rats. Bone metabolism differences among skeletal sites may be problematic when translating experimental results from rats to humans, but data on such differences in rats are lacking. Therefore, we examined the differences in bone structure and metabolism among skeletal sites using the lumbar vertebra (LV), tibia, and iliac bone obtained from ovariectomized or sham-operated rats preoperatively and at various times from 3 days to 26 weeks postoperatively. The trabeculae were thicker in the LV, where bone metabolism was less active than at other sites, and numerous fine trabeculae were observed in the tibia, where bone metabolism was more active. The iliac bone structure and metabolism were intermediate between those of the tibia and LV. Ovariectomy induced lower bone volume and higher bone metabolism in all skeletal sites, but the changes were greatest and occurred earliest in the tibia, followed by the iliac bone and then LV. Ovariectomy caused changes in bone metabolic markers, which occurred earlier than those in bone tissue. Activation frequency (Ac.f) increased after ovariectomy. At week 26 in ovariectomized rats, Ac.f was highest in the tibia (3.13 N/year) but similar between iliac bone (0.87 N/year) and LV (1.39 N/year). Ac.f is reportedly 0.3-0.4 N/year in the iliac bone of postmenopausal women, suggesting that bone turnover in rats is several times higher than in humans. The reference values reported here are useful for translating experimental results from rats to humans.

[Morphological analysis of bone dynamics and metabolic bone disease. Bone histomorphometry for laboratory animals].

The bone histomorphometry is well-known as the histological evaluation method for the investigation of the efficacy of various kinds of medicine on bone metabolism disorder. Recently, in addition, it is indispensable for bone researchers to clarify characteristic of bone metabolism in genetically-modified mice by means of bone histomorphometry. Thus, bone histomorphometry has broad utility. However, it would not be an exaggeration to say that researchers are interested in only numerical value of various kinds of parameters without understanding lots of information obtained from morphological observation. Especially, we have to pay attention to measurement and interpretation of parameters of bone histomorphometry in case of growing bone, because growing bone is changing its size of longitudinal and width. In this review, we would like to explain how to measure with bone histomorphometry for modeling bone in growing animals.

Immunohistochemical distribution of surfactant apoprotein-A in congenital diaphragmatic hernia-II.

Morphometric analyses of the immunohistochemical expression of surfactant apoprotein A (SP-A) were carried out on the bronchioles of human congenital diaphragmatic hernia (CDH) neonates and then compared with those in a gestational and postnatal age-matched control group. There was no difference in SP-A expression between lung specimens of the control group and unaffected lungs in the CDH group. However, compared with both these lungs, the ipsilateral lungs of the CDH group showed a significant increase in SP-A expression, namely, the number of SP-A-positive cells per bronchiole, the number of SP-A-positive cells per unit perimeter of bronchiole, and the number of SP-A-positive cells per unit bronchiolar surface area. These results suggest that in lungs of CDH cases, especially ipsilateral lungs, there is a possible delay in the functional maturation or development of SP-A synthesis by the bronchiole, and this retardation may play a role in the postnatal respiratory insufficiency observed in CDH patients.