亚慢性氟中毒对大鼠骨组织诱导型一氧化氮合酶表达的影响

目的 动态观察亚慢性氟中毒大鼠骨组织中诱导型一氧化氮合酶(iNOS)的表达变化,分析亚慢性氟中毒骨组织中一氧化氮(NO)自由基损伤机制.方法 将雄性Wistar大鼠按体质量随机分成两组.氟化钠组每日饮用含氟150mg/L的水溶液,对照组饮用自来水,共饲养24周,每4周处死一批动物,测定大鼠血清及骨组织中的含氟量,Griess Reagent法检血清NO,RT-PCR法和免疫组化法检测骨组织中iNOSmRNA及蛋白表达.结果 氟化钠组血清NO波动较大,第8周时(19.94±3.04)nmol/L]明显高于对照组(9.11±1.21)nmol/L].差异有统计学意义(t=9.36,P＜0.01),而第20、24周时(11.55±3.54)、(20.83±2.49)nmol/L]明显低于对照组(31.13±3.93)、(33.10±7.37)nmol/L],两组比较差异均有统计学意义(t值分别为10.47、4.46,P＜0.01):第4、8、12、16、20、24周时氟化钠组(1.87±0.11)、(1.87±0.78)、(1.90±0.29)、(1.93±0.67)、(1.88±0.38)、(1.84±0.03)]骨组织iNOS mRNA表达均明显高于对照组(0.41±0.25)、(0.30±0.17)、(0.18±0.06)、(0.63±0.15)、(0.66±0.04)、(0.65±0.55)],两组比较差异均有统计学意义(t值分别为13.09、4.82、14.23、4.64、7.82、5.29.P＜0.01).iNOS蛋白主要表达在干骺端肥大区软骨细胞、关节软骨的深层软骨细胞、成骨细胞和韧带细胞中.结论 高剂量氟可以持续诱导iNOS表达,催化NO合成,通过局部调节成骨细胞和破骨细胞活性参与氟中毒骨转换过程.

Effect of subchronic fluoride intoxication on inducible nitric oxide synthase expression in rat bone tissue

Objective To observe the expressions of inducible nitric oxide synthase(iNOS) in the progress of rat subchronic fluorosis,and analyse the mechanism of nitric oxide(NO) free radical injnry in bone.Methods Male wistar rats were divided randomly by body weight into two groups.i.e.sodium fluoride group and control group.Sodium fluoride group was given drinking water with 150 mg/L sodium fluoride,and control group was given tap water only.The animals were bred for 24 weeks.Every four weeks some rats were killed.The contents of serum and bone fluoride were examined and analyzed.The levels of serum NO were determined by Griess Reagent.The expressions of iNOS mRNA and protein were analyzed by RT-PCR and immunohistochemistry.Results The serum NO contents significantly increased(t=9.36,P＜0.01) in NaF-treated rats after 8 weeks(19.94±3.04)nmol/L],but significantly decreased(t=10.47,4.46,P＜0.01) after 20 weeks(11.55±3.54)nmol/L]and 24 weeks(20.83±2.49)nmol/L],compared with control group(9.11±1.21,31.13±3.93,33.10±7.37)nmol/L].The expression of iNOS mRNA significantly increased(t=13.09,4.82,14.23,4.64,7.82,5.29,P＜0.01)in rats treated with sodium fluoride(1.87±0.11),(1.87±0.78),(1.90±0.29),(1.93±0.67),(1.88±0.38),(1.84±0.03)],compared with control group(0.41±0.25),(0.30±0.17),(0.18±0.06),(0.63±0.15),(0.66±0.04),(0.65±0.55)],and these proteins mainly appeared in hyperplasie zone and hypertrophic zone cells of epiphyseal plate,cartilages,articular cartilage cells,osteoblasts and ligament cells.Conclusions High dose fluoride might persistentlv induce the expressions of iNOS and catalyze synthesis of NO,then regulates osteoblast and osteoclast activitv and finally influences bone turnover.