ABSTRACT
Objective To comprehensively study the oxidative stress of bone tissue in rats with chronic fluorosis treated with anti-oxidant,the oxidative damage of lipid,protein and DNA.Methods Forty Wistar rats weaned 2 weeks were randomized by weight and divided into 4 groups according to body weight,control group (treated with tap water) and 3 NaF (sodium fluoride) exposure groups (treated with NaF at 50,150 and 250 mg/L),5 female rats and 5 male rats in each group.NaF was given through drinking water.After 6 months of treatment,a 12-hour urine samples were collected,then rats were killed,serum was collected,right rear tibiofibula was separated.Bone and urinary fluoride content and incidence rate of dental fluorine were studied and the levels of bone tissue suppression function of hydroxy free radical,superoxide dismutase (SOD),catalase (CAT),glutathione peroxidase (GSH-Px),8-hydroxydeoxyguanosine (8-OHdG),protein carbonyls (PCO),and malonaldehyde (MDA) were assayed.Results ① Results of suppression function of hydroxy free radical:The difference of bone tissue suppression function of hydroxy free radical among control [(22.99 ± 4.31)U/mg prot],low-excess dose [(22.76 ± 8.11)U/mg prot],medium-excess dose [(13.47 ± 4.56)U/mg prot] and high-excess dose [(19.40 ± 5.92)U/mg prot] groups was statistically significant (F =5.01,P ＜0.05).②Results of SOD:The difference of bone tissue SOD among control [(5.06 ± 1.16)U/mg prot],low-excess dose [(5.32 ± 1.18)U/mg prot],medium-excess dose [(3.71 ± 0.72)U/mg prot] and high-excess dose [(4.80 ± 1.10)U/mg prot] groups was statistically significant (F =4.44,P ＜0.05).③ Results of CAT:The difference of bone tissue CAT among control [(25.20 ± 5.91)U/mg prot],low-excess dose [(22.53 ± 7.10) U/mg prot],medium-excess dose [(17.96 ± 4.71)U/mg prot] and high-excess dose [(19.52 ± 5.52)U/ mg prot] groups was statistically significant (F =2.85,P ＜0.05).④Results of GSH-Px:The differences of bone tissue GSH-Px among control [(52.86 ± 12.88)U/mg prot],low-excess dose [(70.05 ± 15.72)U/mg prot],medium-excess dose [(51.55 ± 6.97)U/mg prot] and high-excess dose [(57.47 ± 10.99) U/mg prot] groups was statistically significant (F =4.89,P ＜0.05).⑤Results of PCO:The differences of bone tissue PCO among control [(58.73 ± 20.86)ng/L],low-excess dose [(89.41 ± 26.20)ng/L],medium-excess dose [(97.07 ± 22.24)ng/L] and highexcess dose [(83.96 ± 29.55)ng/L] groups was statistically significant (F =4.43,P ＜0.05).⑥Results of 8-OHdG:The differences of bone tissue 8-OHdG among control [(87.66 ± 6.32)ng/L],low-excess dose [(86.31± 6.30)ng/L],medium-excess dose [(92.17 ± 4.28)ng/L] and high-excess dose [(88.02 ± 6.14)ng/L] groups was not statistically significant (F =1.88,P ＞ 0.05).⑦Results of MDA:The differences of bone tissue MDA among control [(3.70 ± 1.73) nmol/mg prot],low-excess dose [(2.10 ± 0.95)nmol/mg prot],medium-excess dose [(3.32± 2.20)nmol/mg prot] and high-excess dose [(2.71 ± 2.18)nmol/mg prot] groups was not statistically significant (F =1.37,P ＞ 0.05).Conclusions The activity of SOD and CAT of bone tissue are inhibited and suppression function of hydroxy free radical is decreasing under fluorosis influence,which results in protein damage.Oxidative stress is considered to be one of the mechanisms of skeletal fluorosis.