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BACKGROUND:Fluoride treatment of osteoporosis has been controversial.Literatures addressing the effect of fluoride on bone bio-mechanical parameters of femur in young rats are few.OBJECTIVE:To study the effects of fluoride on bone biomechanical parameters of femur in young rats.METHODS:Ninety 2-month-old SPF Sprague Dawley rats,half male and female,were randomly divided into 9 groups:control group(young,adult and long-time)and drug-administered group(young high-fluoride,young low-fluoride,adult high-fluoride,adut low-fluoride,long-term high-fluoride and long-term low-fluoride).Rats in the control group were orally administered with physiological saline,while in the drug-administered group were given orally with different dose fluoride at the corresponding times.After experiment,rats were sacrificed under anaesthesia.Three-point bending test was performed at the left femur.The effects of fluoride on maximum load and rigidity of femur were measured.RESULTS AND CONCLUSION:Compared with young control group,the maximum load and the rigidity of femur in the young high-fluoride group were decreased by 13.18%and 13.61%,respectively(P＜0.05),which had no dramatically difference in the young low-fluoride group.Compared with long-term high-fluoride group,the maximum load and the rigidity offemur in the young high-fluoride were decreased by 17.22%and 17.17%(P＜0.05),which were obvious increased in the long.term low-fluoride grou by 18.33%and 19.15%,respectively(P＜0.05).The maximum load and the rigidity of femur were strengthened in the adult high-fluoride and adult low-fluoride groups(P＜0.05).The results suggested that young rats are more sensitive to high-dose fluoride,which can reduce bone quality in rats.The negative effects on bone quailty of rats were gradually displayed as the prolongation of the period of fluoride.
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This study was aimed to detect the effects of alcohol on bone metabolism and biomechanical property of growing mice. Thirty KM mice were randomly divided into 3 groups, namely basal control group (mice were killed at the beginning), normal control group (with distilled water given by gastrogavage), and 50% (V/V) alcohol group (with alcohol given by gastrogavage at the dose of 4 g x kg(-1) x d(-1) for 60 days). All mice were killed and their proximal tibia and tibial diaphysis were processed by undecalcified sections and measured by bone histomorphometry. The biomechanical properties of lumbar vertebra and femur were tested. Compared with normal control, the index of trabecular bone area (% Tb. Ar) of proximal tibial metaphysis (PTM) and the static parameter of cortical bone( Ct. Ar) both decreased obviously (P < 0.05) in alcohol group. Bone formation rate (BFR/TV) of trabecular bone and cortical bone dropped also (P < 0.05). The maximal resistibility of lumbar vertebra and structural mechanical strength of proximal femoral neck both declined significantly (P < 0.01) in alcohol group. Low dose of alcohol inhibited the bone formation rate of growing mice , thus leading to a disorder of bone metabolism and a decrease in biomechanical quality.
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Animais , Feminino , Masculino , Camundongos , Fenômenos Biomecânicos , Densidade Óssea , Osso e Ossos , Metabolismo , Etanol , Farmacologia , Distribuição AleatóriaRESUMO
BACKGROUND:The mechanical properties of monkeys are the closest to the human body.Monkey is the ideal animal model of osteoporosis research.OBJECTIVE:To explore the biomechanical properties of the long bones and vertebrae in rhesus monkeys.DESIGN.TIME AND SETTING:The mechanics experiment for the study was based on monkeys,which was completed in the South Medical University,Key Laboratory of Medical Biomechanics in Octobor 2006.MATERIALS:Four male macaca mulattas aged 17.5 years on average and three female crab-eating monkeys aged 9 years on average.METHODS:Long bones(femur,tibia,fibula,humerus,radius and ulna)and the third and fourth lumbar vertebrae of three adult crab-eating monkeys and four old macaca mulattes were teken to do four-point bending test,torsion test,indentation test and compression test respectively.MAIN OUTCOME MEASURES:①The results of compression experiments and indentation experiments in monkey vertebrae.②The maximum load and the rigidity factor in left side of long bone of monkeys.③The maximum torque(N·m)in the right side of long bone of monkeys.RESULTS:①In the four-point bending tests,the maximum Ioad of the left ulna,fibula,humerus,femur,tibia and radius in macaca mulattas were(574.16±163.53),(179.98±38.32),(1487.9±965.12),(1928.60±336.23),(1303.23±969.35),(559.92±1.12)N,respectively.While the rigidity factor of the left femur,tibia,fibula,humerus,radius and ulna in macaca mulattas were (53.49±14.22),(28.41±5.86),(114.22±13.24),(142.16±18.56).(101.11±15.46),(69.13±5.54)N/mm,respectively.The maximum load of the left femur,tibia.fibula,humerus,radius and ulna in crab-eating monkeys were(179.93±19.38),(53.82±5.31),(631.61±225.81),(726.07±245.69),(424.52±49.s0),(1 91.97±67.73)N,respectively;however,the rigidity factor of the left femur,tibia,fibula,humerus,radius and ulna in crab-eating monkeys were(21.45±2.63),(16.25±6.66),(68.5±12.22),(76.79±14.01),(41.80±2.79),(64.31±15.89)N/mm,respectively.②In the torsion test,the maximum torque of the right fibula,humerus,femur and tibia in macaca mulattas were(1.55±0.82),(22.26±4.26),(30.93±6.54),(17.49±4.04)N·m,respectively.The maximum torqua of the right fibula,humerus,femur,tibia in crab-eating monkeys were(0.81±0.15),(10.34±2.06),(11.58±0.76),(6.68±1.34)N·m,respectively;③In the compression test,the maximal compression load and the rigidity factor of L4 in macaca mulattas were (2811.21±403.90)N,and(69.47±8.92)N/mm,respectively;the maximal compression load and the rigidity factor of L4 in crab-eating monkeys were(1659.90±339.08)N,and(36.29±6.61)N/mm,respectively.④In the indentation test,the maximal indentation and the maximal anti-pressure of L_3 in macaca mulattas were(521.90±38.94)N,and(699.16±43.46)MPa,respectively;the maximal indentation and the maximal anti-pressure of L_3 in crab-eating monkeys were(614±145.94)N,and (815.92±193.69)MPa,respectively.CONCLUSION:Experimental data derived from the experiments demonstrated that rhesus monkeys as a kind of nonhuman primate animals have an important reference value in the animal studies of osteoporosis.
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Objective To investigate the possible mechanism of the effect of short-term gonadotropin-re-leasing hormone agonist(GnRHa)on linear growth in female pubertal rats. Methods Forty 3-week-old female rats were randomly divided into 5 groups(n=8 each). One group was sacrificed as base-line control. Group OVX was operated for ovariectomy at the beginning of experiment. Group Gn and group E2 each received two intramuscu-lar injections of 2.5mg·kg-1 triptorelin 2 weeks apart, and group E2 received additional daily 1μg·kg-1·d-1estradiol(E2)s. c. at three days after the second GnRHa injection for 11 days. Group Ctrl was sham-operated ascontrol. Each rat, except for the base-line control group. received 30mg/kg oxytetracycline s. c. and 20mg/kgcalcein s. c. 9 and 2 days respectively before sacrifice. Hepatic GH receptor mRNA, insulin-like growth factor(IGF)-I and IGF binding protein(IGFBP)-3, circulating IGF-I and IGFBP-3, local IGF-I/IGF-I receptor(IGF-IR)and proliferation rate(PFR)in epiphyseal growth plate(EGP)were evaluated after 4-week treatment.Results Similar to group OVX, the rats in group Gn became taller and heavier than group Ctrl with greater tibial length, wider EGP, greater longitudinal growth rate(LGR)and higher PFR(P<0.05 or P<0.01). Estrogen supplement reversed the effect of GnRHa. There was no statistical difference among the 4 groups regarding plasma IGF-I and IGFBP-3, hepatic IGF-I and IGFBP-3 mRNA levels, local IGF-I and IGF-I R levels in EGF. GnRHa down-regulated hepatic GHR mRNA expression, which was reversed by estrogen supplement. Conclusion GnRHa accelerates longitudinal growth of female pubertal rats. Estrogen deprivation contributes to GnRHa-induced alteration of linear growth in female rats, through improving PFR and suppressing the senescence of EGP. The underlying mechanism does not attribute to endocrine change of GH/IGF-I axis or local IGF-I/IGF-IR in EGP.
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AIM To evaluate whether l glutamine monofluorophosphate(MFP) together with Alendronate sodium may further increase bone mass in ovariectomized rats. METHODS Forty two 3 month old Sprague Dawley female rats were randomized into six groups:group 1 rats were sham operated(Sham),group 2 rats were ovariectomized controls(Ovx),and groups 3～6 were ovariectomized and received either 1 mg?kg -1 ?d -1 of alendronate sodium ,270 mg?kg -1 ?d -1 of calcium gluconate,5 6 mg?kg -1 ?d -1 of MFP or combination of 5 6 mg?kg -1 ?d -1 of MFP and 1 mg?kg -1 ?d -1 of alendronate sodium for 3 months. All animals received double bone fluorochrome labeling prior to sacrifice. At the end of experiment,the left tibiae were havested for histomorphometrical evaluations. RESULTS Alendronate sodium increased trabecular bone volume significantly with suppressed bone resorption and bone formation. Administrated calcium gluconate had no influence on the bone mass. MFP also could not restore cancellous bone of ovariectomized rats. Administration of both MFP and alendronate sodium increased bone mass significantly but did not increase bone mass compared with alendronate sodium. CONCLUSIONS The results indicated administration of both alendronate sodium and MFP could not further increase bone mass of ovariectomized rats.
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Objective:To investigate the effect of a low calcium diet on the distal and proximal tibial metaphysis in male rats using bone histomorphometrical techniques. Methods:Forty 3-month-old male Sprague-Dawley(SD) rats, with a mean weight of 280?22g, were randomized into five groups. Group one and group two were fed a normal diet (Ca 1.0%) and a very low calcium diet (VLCD ,Ca 0.1%) respectively for one month,and the rest three groups were fed a normal diet (Ca 1.0%), a very low calcium diet (VLCD, Ca 0.1%) and a low calcium diet (LCD , Ca 0.3%) respectively for three months. All animals received double bone fluorochrome labeling prior to sacrifice. At the end of experiment, the left tibiae were harvested for bone histomorphometrical evaluations. Results:After one month, compared to control group, distal tibial metaphysis(DTM) of VLCD did not change significantly but proximal tibial metaphysis(PTM) was decreased significantly whose percent trabecular area (%Tb.Ar) was decreased to 38% (P