ultrastructural studies of osteoblast cells in osteopetrotic op/op mouse

introduction: the osteopetrosis is a common disease in man and animals which is characterized by calcium accumulation in bones. the purpose of this study is to eveluate the osteoblast ultrastructure in osteoptrotic op/op mouse. material and methods: in this study 5 op/op (experimental) and 5 control mouse were killed by overdose of choloroform. their femur bones were taken, decalcified by edta, fiexed in glutaraldehyde and osmium tetroxide, embeded in epon, sectioned by diamond knife, stained by lead citrate and uranil acetate and photographed by transmission electron microscope (hitachi 800, japan). results: the ultrastructural observation of osteoblast cells revealed a decrease in the mitochonderia and endoplasmic reticulum in of op/op mouse, but the cytoplasmic vacuoles and free ribosomes were high. the nuclear envelope in op/op group was irregular and higher chromatin density. also, the osteoid in op/op group was thickened. conclusion: the activity of osteoblast was decreased due to the inactivity of osteoclast as a result of lack macrophage colony stimulating factor.