Nuclear profile area of osteoblasts in normal, osteoporotic, and fluoride treated subjects

Abstract

Osteoblasts undergo changes both in shape (progressive flattening) and function (progressive decline in matrix synthesis) during their life span. Nuclear volume, apart from changing systematically during their cell cycle, is believed to be a general index of cell vigor. Accordingly, we measured the nuclear profile area of osteoblasts classified as pre (Group I), cuboidal (Group 11), intermediate (Group III), and terminal (Group IV) in iliac cancellous bone in 6 premenopausal normals, mean age in years (SD) 40.2 (4.8), 5 postmenopausal normals, age 65.8 (2.4), 15 postmenopausal osteoporotics, age 65.3 (4.9), 5 patients with fluorideinduced osteomalacia, age 69.2 (5.0), and two patients with endemic fluorosis, age 70.5 (5.5). A total number of 4,085 osteoblast nuclei were examined and measured. In each group there was a systematic decline in nuclear profile area through stages I-IV, corresponding to an average decline in nuclear volulne of greater than 90%. The inajor difference among groups was that in type I1 (cuboidal) osteoblasts, nuclear profile area was significantly greater in premenopausal normals than in the other four groups, which did not differ significantly. The effect seems to be related to age, rather than to disease or treatment. The fitnctional significance of this age-related morphologic change remains to be determined, but it may be related to the decline in apposition rate with age. (The J Histoteclztzol 19:3 13-3 15, 1996) ogy and tetracycline labeling, kinetics of matrix and mineral apposition rates, and the relationship of turnover and cell morphology (1,2). The changes we found were relatively high proportion of cuboidal (Type 11) osteoblasts associated with thick osteoid seams, a moderate proportion of intermediate (Type 111) osteoblasts linked with normal osteoid thickness, and a considerable proportion of flat (Type IV) osteoblasts associated with thin osteoid seams. More recently we measured the nuclear profile area of different types of osteoblasts at the cancellous bone surface in transiliac biopsy cores from a group of patients classified as premenopausal normals, postmenopausal normals, postmenopausal osteoporotics, fluoride-induced osteomalacia and endemic fluorosis. The current report is to present our study with data on the distribution and nuclear profile area of various types of osteoblasts at the cancellous bone surface from biopsies collected in Henry Ford Hospital's Bone and Mineral Research Laboratory. . Materials and Methods Specii7zeizs The materials consisted of transiliac bone biopsy cores from 33 white female subjects. Six patients were healthy normal premenopausal (N.Pre), mean age 40.2 -t 4.8, and 5 patients were normal postlnenopausal (N.Post), mean age 65.8 + 2.4, who were selected and considered ~netabolicafi~