铝氟联合作用对大鼠骨生长和代谢影响的性别差异

Effects of aluminum and fluoride co-exposure on longitudinal bone growth and bone metabolism in different gender rats

目的通过骨形态计量学方法观察铝氟联合摄入对不同性别大鼠纵向骨生长及松质骨代谢的影响。方法40只2月龄清洁级SD大鼠,雌雄各半,随机分成正常对照组(生理盐水)、铝+低氟组(0.1 mg/kg+5 mg/kg)、铝+中氟组(0.1 mg/kg+15 mg/kg)、铝+高氟组(0.1 mg/kg+30 mg/kg),每日灌胃1次,连续12周。实验结束时取胫骨近心端进行不脱钙骨切片和骨染色,观察生长板软骨以及干骺端骨小梁微结构改变,并进行骨代谢的定量分析。结果与对照组相比,铝+高氟组大鼠生长板总厚度增加(P<0.01),且雄性大鼠出现凋亡软骨细胞。随氟染毒剂量的升高,初级小梁厚度(P.Tb.Wi)、骨小梁荧光周长(MS)、矿化沉积率(MAR)、骨形成率(BFR)等以及骨吸收周长(Er.S)均先升高(与对照组比较,P<0.05或P<0.01)后下降到接近对照组,铝+高氟组雄性的初级小梁厚度及骨形成参数甚至低于对照组(P<0.05)。与对照组相比,铝+高氟组骨小梁体积(BV)、骨小梁数量(Tb.N)减少,小梁分离度(Tb.Sp)增加(P<0.05),雌雄改变一致。结论铝和低剂量氟联合作用促进雌雄大鼠骨形成;铝和高剂量氟联合作用则抑制骨生长、抑制次级小梁骨形成和吸收,对雄性大鼠的效应更为明显。

Objective To study the effects of aluminum and fluoride co-exposure on longitudinal bone growth and bone metabolism in different gender rats through bone histomorphometry.Methods Forty 2-month-old Sprague-Dawley rats,half male and half female,were randomly divided into the control group(normal saline)and three treatment groups,such as aluminum[0.1 mg/(kg·d)]+low fluoride[5 mg/(kg·d)]group,aluminum[0.1 mg/(kg·d)]+moderate fluoride[15 mg/(kg·d)]and aluminum[0.1 mg/(kg·d)]+high fluoride[15 mg/(kg·d)]group,the rats were given aluminum and fluoride by gavage respectively once a day for three consecutive months.At the end of the experiment,all proximal tibias were collected and processed for undecalcified bone section and stain,and microstructural feature of trabecular in epiphyseal growth plate and metaphysis were evaluated quantitatively,analysis of the metaphyseal trabecular metabolism was also conducted.Results The width of growth plate expanded only in aluminum+high fluoride group and apoptosis chondrocyte was shown only in male rats compared with the control(P<0.05).With the increase of fluoride exposure level,the primary trabecular width(P.Tb.Wi),trabecular mineralizing surface(MS),mineralizing deposition rate(MAR),bone formation rate(BFR)and eroded surface(Er.S)increased significantly(compared with control group,P<0.05 or P<0.01),then decreased to normal levels(P>0.05).The P.Tb.Wi and BFR in male rats in aluminum+high fluoride group were lower even than that in control(P<0.05).Compared with the control group,the trabecular bone volume(BV)and number(Tb.N)decreased while trabecular separation(Tb.Sp)increased both in male and female rats in aluminum+high fluoride group(P<0.05).Conclusion Aluminum and low dose fluoride in combination may promote the bone formation both in male and female rats,and aluminum and high dose fluoride in combination may inhibit not only the bone formation,but also bone longitudinal growth along with bone resorption,and the response in male rats is more sensitive.