RESUMO
Background: Due to technical difficulties of in vivo observation of blood flow and microvessels in bone, no study has been done concerning the role of blood flow in bone remodeling. Objective: To develop a new window chamber for microscopic observation of the microcirculation in living bone, and to examine the utility of the chamber using rat femur in health and diseases. Methods: A stainless chamber (19 mm in diameter and 5 mm in height) with a circular window (7.5 mm in diameter) for microscopic observation was developed. The chamber was put on rat femur which was exposed for direct observation of the microvasculature. Intravital observation was made of bone blood flow and microvessels, using fluorescence videomicroscopy and confocal laser microscopy. The utility of the chamber was examined based on images of microcirculation (normal and abnormal) in the femur bone. Results and conclusions: Images of rat femur microvasculature were enhanced in the quality by use of the femur window chamber. The new chamber provides a powerful tool for in vivo studies of the bone microcirculation in health and diseases.
RESUMO
Background: Estrogen synthesis decreases in the postmenopausal period inducing gingival periodontal disturbance. Estrogen replacement therapy has been used to reduce such gingival complications, although it has been limited by the adverse effect of estrogen. Objective: To investigate the effects of supplementation of genistein, a phytoestrogen derived from the soybean, on blood flow disturbance in the gingiva after menopause, using an ovariectomized rat model. Materials and methods: Female Wistar rats (220 - 280 g) were subjected to a bilateral ovariectomy (OVX rats). The rats were classified into four groups: sham-operated animals treated with vehicle (DMSO 100 μl/day,s.c) (Sham (veh); n = 6), OVX rats treated with vehicle (DMSO 100 μl/day,s.c) (OVX (veh); n = 6), OVX rats treated with 17β-estradiol (20 μg/kg/day,s.c) (OVX (E₂); n = 6) and OVX treated with genistein (0.25 mg/kg.BW/day,s.c) (OVX (gen); n = 6). Plasma estradiol, body weight, and gingival blood flow (GBF) were measured 3 weeks after OVX. For the GBF measurement, laser Doppler perfusion flowmetry was used. Results: Three weeks after OVX, plasma estradiol levels in three groups of OVX rats were significantly lower than the sham-operated control (p \< 0.05). Body weight increased in OVX (veh) and OVX (gen) groups (p \< 0.001). The GBF increased significantly in OVX (veh) compared to the Sham (veh) group (p \< 0.05), indicating that GBF disturbance due to the lack of estrogen was improved by oral supplemention of 17β-estradiol or genistein. Conclusion: Genistein supplementation improves disturbed gingival blood flow induced in ovariectomized-rats. Genistein might have oral health benefits after menopause.