[Quantitative variations of osteocalcin in the culture media of bones subjected to intermittent mechanical loads in vitro].
A study has been carried out on the dynamics of the osteogenesis induced in vitro by an intermittent mechanical load applied on intact metatarsals isolated from 12 day-old rats. The metatarsals, as soon as isolated, were deprived of both the ends and placed in culture medium (BGJb enriched with 10% FCS, 65 micrograms of ascorbic acid, penicillin, strepto) without a mechanical load. After 4-5 hours, half the bones were placed in our device, described in our previous paper (2), and submitted to a daily cycle of an intermittent mechanical load (11.6 g/mm2) 1/2 h long, at 1 Hz frequency. The remaining bones, used as control, were cultured in the same medium, without any mechanical load. 24, 48 and 72 hours from the first application of the load the bones were fixed, embedded (decalcified or undecalcified) and serially sectioned. The sections were stained with toluidin blu and trichromic Masson-Goldner. On the perimeter of 5 non-consecutive sections of each bone the number of the osteoblasts at 250x, and the nuclear volume of the same cells at 1000x were evaluated. In the culture media the alcaline phosphatase activity (p-nitrophenol as substrate) and the concentration of osteocalcin (RIA) were measured. The number and nuclear volume of the osteoblasts are higher in the loaded than in the control bones (tab. 1). The alcaline phosphatase activity does not vary in the control bones between 24 and 72 h, while it increases in the loaded bones. The concentration of the osteocalcin shows a slight increase at 48 h in the control bones, and a significant decrease int he loaded bones (fig. 1).(ABSTRACT TRUNCATED AT 250 WORDS)
Lozupone
E
E
Istituto di Anatomia Umana Normale, Università di Bari.
Favia
A
A
Cafagna
B
B
Cantatore
F P
FP
D000469:Alkaline Phosphatase / Q000032:analysis; D000818:Animals; D001842:Bone and Bones / Q000166:cytology / Q000378:metabolism*; D002452:Cell Count; D002467:Cell Nucleus / Q000648:ultrastructure; D048429:Cell Size; D017077:Culture Media, Conditioned / Q000737:chemistry / Q000378:metabolism*; D008684:Metatarsus; D009924:Organ Culture Techniques; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D015675:Osteocalcin / Q000032:analysis / Q000096:biosynthesis*; D010012:Osteogenesis; D051381:Rats; D016474:Weight-Bearing
D017077:Culture Media, Conditioned; D015675:Osteocalcin; D000469:Alkaline Phosphatase
Variazioni quantitative dell'osteocalcina nel terreno di cultura di ossa sottoposte a carico meccanico intermittente in vitro.