| Since the 1960s, pulsed electromagnetic fields (PEMFs) have been used to treat various kinds of bone diseases such as delayed union, nonunion and osteoporosis without incursive damage. PEMFs could improve the proliferation and differentiation of live cells, stimulate the appearance of the local factors, and meliorate the bone density and biomechanics trait of thighbone. Osteoblast (OB) plays a vital role in the formation and maturity of bone. It could synthesize and secrete the collagen and glucoprotin making up the bone matrix, and also form bone tissue by calcifying the bone matrix. In addition, OB has significant effects on keeping balance of internal environment, regulating physiological mechanism, explaining bone metabolic diseases, etc. Ionic channel is a sort of protein structure on membrane, which serves as the basis of generating bioelectricity in nerve cells, skeletal muscle cells and cardiac muscle cells. It has been proved by many experiments that the mechanism of electromagnetic field affecting bone tissues is concerned with calcium ion. Calcium ion might mediate the proliferation of bone cells induced by electromagnetic field. There are various kinds of electrostimulation which may increase the density of calcium ion in cytochyma. With the increasing coupling force of electromagnetic field, the activity of calcium ion would be improved. The electromagnetic fields have significant effects on changing permeation degree and bioactivity of calcium ionic channel.This experiment was designed to observe the treating effects of PEMFs on osteoporosis. The effects of PEMFs on osteoporosis SD rats were testified by measuring biochemical indicators. MTT assay, calcium nodal stain were used to observe the proliferation and differentiation of OB. Patch clamp was used to measure activity of calcium ionic channel of OB. In the present research, the relationship between proliferation of osteoblast and activity of calcium ionic channel was briefly discussed. The results of this study may provide some evidence to treat osteoporosis.1.Effects of PEMFs on biochemical indicators and bone biomechanics of osteoporosis ratsOBJECTIVE: To observe the effects of PEMFs on the biochemical indicators and bone biomechanics of ovariectomy-induced osteoporotic rats. METHTHODS: 30 female SD rats were divided into 3 groups (n=10) randomly. The name of each group was Sham, Model and PEMFs respectively. After 4 weeks, we anesthetized the rats by using Pentobarbital Sodium (25mg·Kg-1). Then the Model group and PEMFs group were ovariectomized. According to the experimental design, we used Helmholtz coils to generate uniform magnetic field. After 4-week breeding, The PEMFs group was exposed to 15Hz PEMFs (2Gs, 8h/d), while the Sham group and Model group were not exposed to PEMFs. After 8 weeks, the changes in serum alkaline phosphatase (ALP), serum calcium (Ca2+), urinary ALP, urinary Ca2+ and bone stress force were examined. RESULTS: (1) ALP, Ca2+ assay results: Compared with the Model group, significant difference (P<0.05) was found in the value of ALP and Ca2+ in PEMFs group. In blood serum, the value of ALP of Model group was (275.16±228.57), and the value of ALP of PEMFs group was (179.30±87.68). The value of Ca2+ of Model group was (2.66±0.13), and the value of Ca2+ of PEMFs group was (2.52±0.05). (2) Bone stress force assay results: The value of Model group was (923.60±34.15 kPa), and the value of PEMFs group was (1152.85±118.20 kPa). The difference between them was significant (P<0.05). CONCLUSION: The PEMFs could promote bone reconstitution, increase Ca2+ resorption and boost recover of bone stress force.2.OB isolated and culturedOBJECTIVE: To study a simple and effective method to isolate OB from rats. METHTHODS: The OB was obtained by using tissue mass method and were purified by differential speed attachment method. Draw the growth carves of OB. Then alkaline phosphatase stain was practiced. RESULTS: The configuration of OB was favorable, and the growth carves showed typical"S". The result of stains was positive, meaning that the cells were classical OB. CONCLUSION: The method could be used to obtain OB simply and effectively. It was the material basis for further experiments.3. Effects of PEMFs on activity of calcium ionic channelOBJECTIVE: To observe the influence of PEMFs on the activity of calcium ionic channel. METHTHODS: The OBs were divided into 3 groups, namely, control group, temp group and regular group. The regular group was exposed to 15Hz PEMFs (2Gs, 30min/d), while the control group and temp group were not. After 3 days, the temp group was exposed to 15Hz PEMFs (2Gs) in 30 minutes. Then patch clamp was used to obtain datum. RESULTS: The relationship between calcium ion current and stimulating voltage was discussed. The current of calcium ion was active at -30mV. The depolarization of membrane potential was observed to occur since stimulating voltage growing higher, and the value of current reached peak at 0mV. The current value was negative because it was an inward calcium ionic current. In this experiment, significant difference within the three groups was observed (P<0.05). CONCLUSION: After exposing to PEMFs, the activity of calcium ionic channel could be improved, including transient and accumulative effect.
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