过量氟摄入对大鼠骨组织氧化应激的影响

Impact of excessive fluoride intake on bone tissue oxidative stress

目的观察过量氟摄入对大鼠骨组织氧化应激的影响。方法将40只断乳2周的Wistar大鼠按体质量采用随机数字表法分为4组，分别为对照组（自来水）和低过剂量氟组[含50mg／L氟化钠（NaF）自来水1、中过剂量氟组（含150mg／LNaF自来水）、高过剂量氟组（含250mg／LNaF自来水），每组10只，雌雄各半，采用自由饮用的方式进行染毒，连续染毒6个月。染毒结束后，收集大鼠的12h尿液，处死大鼠采集血液，分离右后胫腓骨。检测大鼠尿氟、血清氟及骨氟含量及氟斑牙发生率，并检测大鼠骨组织中抑制羟自由基能力，过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GSH—Px）、超氧化物歧化酶（SOD）的活力及8．羟基脱氧鸟苷（8．OHdG）、蛋白质羰基（PCO）、丙二醛（MDA）的含量。结果①抑制羟自由基能力测定结果：对照组，低、中、高过剂量氟组的抑制羟自由基能力分别为（22．99±4．31）、（22．76±8．11）、（13．47±4．56）、（19．40±5．92）U／mgprot，各组比较差异有统计学意义（F=5．01，P〈0．05）。@）SOD测定结果：对照组，低、中、高过剂量氟组的SOD分别为（5．06±1．16）、（5．32±1．18）、（3．71±0．72）、（4．80±1．10）U／mgprot，各组比较差异有统计学意义（F=4．44，P〈0．05）。③CAT测定结果：对照组，低、中、高过剂量氟组的CAT分别为（25．20±5．91）、（22．53±7．10）、（17．96±4．71）、（19．52±5．52）U／gprot，各组比较差异有统计学意义（F=2．85，P〈0．05）。@GSH-Px测定结果：对照组，低、中、高过剂量氟组的GSH．P][分别为（52．86±12．88）、（70．05±15．72）、（51．55±6．97）、（57．47±10．99）U／mgprot，各组比较差异有统计学意义（F：4．89，P〈0．05）。（1）PCO测定结果：对照组，低、中、高过剂量氟组的PCO分别为（58．73±20．86）、（89．41±26．20）、（97．07±22．24）、（83．96±29．55）ng／L，各组比较差异有统计学意义（F=4．43，P〈0．05）。⑥8-OHdG测定结果：对照组，低、中、高过剂量氟组的8-OHdG分别为（87．66±6．32）、（86．31±6．30）、（92．17±4．28）、（88．02±6．14）ng／L，各组比较差异无统计学意义（F=1．88，P〉0．05）。⑦MDA测定结果：对照组，低、中、高过剂量氟组的MDA分别为（3．70±1．73）、（2．10±0．95）、（3．32±2．20）、（2．71±2．18）nmol／mgprot，各组比较差异无统计学意义（F=1．37，P〉0．05）。结论①慢性氟中毒可使大鼠骨组织抑制羟自由基能力下降及SOD及CAT的活性受到抑制致蛋白质受到氧化损伤。②氧化应激是氟骨症发生的机制之一。

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 mgL）, 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 earbonyls （PCO）, and malonaldehyde （MDA） were assayed.Results 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）. @Results 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/rag prot] groups was statistically significant （F = 4.44, P 〈 0.05）. （2） Results of CAT： The difference of bone tissue CAT among control [（25.20 ± 5.91）U/rag 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）. Results of GSH-Px： The differences of bone tissue GSH-Px among control [（52.86 ±12.88）U/rag prot], low-excess dose [（70.05 ± 15.72）U/mg pro 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）.Results 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 high- excess dose [（83.96 ± 29.55）ng/L] groups was statistically significant （F = 4.43, P 〈 0.05）. Results 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）. （2）Results 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.