慢性氟中毒大鼠肾脏自由基含量与形态学变化

目的研究慢性氟中毒大鼠肾脏自由基含量与形态学变化的关系。方法wistar大鼠随机分为三组。正常对照组,未作任何处理;染氟组,自由饮用含氟化钠132．6mg／L的含氟水;抗氧化中药一染氟组,自由饮用含氟化钠132．6mg／L的含氟水,同时每日经腹腔内注射抗氧化中药丹参绞股蓝复方3．125毫克／公斤／天,实验6个月时检查动物。用电子自旋共振的方法检测肾组织内自由基的含量,并观察肾脏的形态学变化。结果与正常对照组动物相比,染氟组自由基明显升高,电镜下见肾小管上皮细胞有巨大线粒体及髓鞘样结构形成,内质网扩张,粗面内质网上核糖体脱落,细胞浆内游离核糖体增加,胞核内异染色质有向核膜下聚集的趋势;光镜下呈颗粒性变,偶见坏死。抗氧化中药一染氟组肾组织中自由基含量不增高,光镜及电镜下均未见明显病变。结论慢性氟中毒时肾脏病变与自由基含量增多有密切关系。     

硒、钼、硼对氟中毒大鼠氟斑牙发生的影响

目的 研究硒、钼、硼对氟中毒大鼠的氟斑牙发生的影响.方法 Wristar大鼠随机分为8组(雌雄各半):硒1组、硒2组、钼1组、钼2组、硼1组、硼2组、氟组、对照组.各组均喂以舍F-45mg/L的蒸馏水及舍不同浓度微量元素的饲料,观察大鼠的一般情况,氟斑牙的发生.结果 硒组体质量增加与对照组接近,优于钼组和硼组(P＜0....     

Effects of fluoride on the expression of NCAM, oxidative stress, and apoptosis in primary cultured hippocampal neurons

The mechanisms underlying the neurotoxicity of endemic fluorosis still remain unknown. To investigate the expression level of neural cell adhesion molecules (NCAM), oxidative stress, and apoptosis induced by fluoride, the primary rat hippocampal neurons were incubated with 20, 40, and 80 mg/l sodium fluoride for 24 h in vitro. The results showed that the cell survival rate in the 80 mg/l fluoride-treated group was significantly lower than that of the control group. Forty and 80 mg/l of fluoride induced significantly increased lactate dehydrogenase release, intracellular reactive oxygen species, and the percentage of apoptosis. Compared with control group, the malondialdehyde levels were significantly elevated while glutathione levels and glutathione peroxidase activities were decreased in all fluoride-treated groups, accompanied by the markedly reduced superoxide dismutase activity in 80 mg/l fluoride-treated group. With respect to NCAM mRNA expression levels, a significant dose-dependent decrease was observed in 40 and 80 mg/l fluoride-treated groups against the control group. In addition, as compared to the control group, the protein expression levels of NCAM-180 in 40 and 80 mg/l fluoride-treated groups, NCAM-140 in all fluoride-treated groups, and NCAM-120 in the 80 mg/l fluoride-treated group were significantly decreased. Our study herein suggested that fluoride could cause oxidative stress, apoptosis, and decreased mRNA and protein expression levels of NCAM in rat hippocampal neurons, contributing to the neurotoxicity induced by fluoride.     

Effects of fluoride on DNA damage, S-phase cell-cycle arrest and the expression of NF-kappaB in primary cultured rat hippocampal neurons

The mechanisms underlying the neurotoxicity of fluorosis still remain obscure. To investigate DNA damage, cell-cycle distribution and expression of nuclear factor kappa B (NF-kappaB) induced by fluoride, the primary rat hippocampal neurons were incubated with various concentrations (20mg/l, 40 mg/l, and 80 mg/l) of sodium fluoride for 24 h in vitro. Our results showed that olive tail moments (OTMs) were significantly elevated in all fluoride-treated groups, while significant increases in the percentage of DNA in the tail were, respectively, observed at 40 mg/l and 80 mg/l levels of fluoride. An increase in the proportion of cells in S-phase was observed in response to the treatment of 40 mg/l and 80 mg/l fluoride. Gene expression of NF-kappaB was also enhanced by fluoride treatment in a dose-dependent manner. The results indicated that fluoride could induce S-phase cell-cycle arrest, up-regulation of NF-kappaB and DNA damage in primary rat hippocampal neurons.     

Effects of sodium fluoride on hyperactivation and Ca2+ signaling pathway in sperm from mice: an in vivo study

Sperm hyperactivation is crucial for a successful fertilization; however, the influence of fluoride (F) to hyperactivation is still in its infancy. The purpose of this study was to investigate the effect of sodium fluoride (NaF) on sperm hyperactivation, Ca²⁺/CALM-CAMK2 signaling, and CatSper1 and CatSper2 mRNA expression in mice sperm. Adult male Kunming mice were administrated with 30, 70, and 150 mg NaF/l (corresponding to 2.84 ± 0.29, 6.28 ± 0.61, and 14.18 ± 1.00 mg F/kg body weight per day) through drinking water for 49 days. The results showed that NaF reduced the sperm hyperactivated motility in a dose-dependent manner. Compared with the controls, intracellular Ca²⁺ concentration and CAMK2 protein were significantly decreased in mice treated with 70 and 150 mg NaF/l, while no effect on CALM was determined in all treatment groups. Furthermore, decreased sperm CatSper1 mRNA expression was also observed in response to middle and higher doses of NaF (70, 150 mg/l) with comparison to the control group, whereas no change in the mRNA expression of CatSper2 was detected in NaF administrated groups. Treatment with 30 mg NaF/l exhibited slight effects on the above indexes with no statistical difference. These findings indicated that exposure to 70 and 150 mg/l NaF for 49 days could result in low hyperactivation via alteration of Ca²⁺ signaling pathway involving CatSper1 in sperm from mice.     

Protein and mRNA expression of Shh,Smo and Gli1 and inhibition by cyclopamine in hepatocytes of rats with chronic fluorosis

In order to investigate the Sonic hedgehog (Shh) signaling pathway and the effect of cyclopamine in rat hepatocytes with chronic fluorosis, 48 Wistar rats were randomly divided into 4 groups. The control group was provided with tap water in which the fluorine concentration was <1 mg/L, while the remaining three groups were provided with water containing sodium fluoride (NaF) at a concentration of 50 mg/L. After 6 months, the blocking and blocking control groups were injected intraperitoneally once every 2 days for 6 days with 10 mg/kg cyclopamine or dimethyl sulfoxide, respectively. The urinary and skeletal fluoride contents were determined by the ion selective electrode method. Levels of aspartate transaminase (AST), alanine transaminase (ALT), total protein (TP) and albumin (Alb) in the serum were determined by using autobiochemical machine. Histological changes in liver tissue were evaluated with Hematoxylin & Eeosin (H&E) staining using light microscopy. The protein and mRNA expression of Shh, Smo and Gli1 in hepatocytes of experimental animals was determined by immunohistochemistry (IHC), Western blotting (Wb) and Real-time quantitative PCR (RT-qPCR). Fluoride content of the urine and bone was increased in the fluorosis and blocking groups compared to those in the control group (P < 0.05), while fluoride content in the blocking group was decreased compared to the fluorosis and blocking control groups (P < 0.05). The expression of Shh, Smo and Gli1 at the mRNA and protein levels was significantly increased in hepatocytes from the fluorosis and blocking control groups compared with the control group, and expression in the blocking group was lower than that of the fluorosis and blocking control groups. The difference between any two groups was considered to be statistically significant (P < 0.05). Taken together, our study indicates that the expression of Shh, Smo and Gli1 at the protein and mRNA level in hepatocytes of rats with chronic fluorosis can be increased by fluoride and may be inhibited by cyclopamine and that the Shh signaling pathway plays an important role in the liver pathogenesis caused by fluorosis.     

肾小管上皮细胞线粒体氧化损伤在肾间质纤维化中的病理学机制研究

目的：研究肾小管上皮细胞线粒体氧化损伤在肾间质纤维化中的病理学机制。方法：80只雄性大鼠随机平分为假手术组和UUO模型组,每组40只,行大鼠左侧输尿管结扎术,假手术组游离左侧输尿管但不予结扎,其余手术与UUO模型组相同。分别于术后d3、d7、d10、d14、d21每组处死8只,取大鼠左侧肾脏。①检测并比较假手术组和UUO模型组大鼠线粒体相关基因的表达水平;②检测两组大鼠肾脏组织COX和SOD含量变化;③检测两组大鼠肾脏组织RIF指数变化;④检测并比较肾体比、肾功能和肾组织Hyp含量动态变化。结果：与假手术组大鼠相比,①UUO模型组大鼠的线粒体相关基因的表达水平显著升高（P＜0.05）,包括线粒体mtDNA、再生基因（PGC1a、NRF1和Tfam）、断裂基因（Mfn1、Mfn2和Opa1）和融合基因（Drp1和Fis1）;②UUO模型组大鼠在造模后10d、14d和21d,肾脏组织中的COX水平显著升高（P＜0.05）,SOD水平显著降低（P＜0.05）,造模时间越长,UUO模型组大鼠COX水平越高（P＜0.05）,SOD水平越低;③UUO模型组大鼠造模后10d、14d和21d,肾脏组织RIF指数均显著升高（P＜0.05）;④UUO模型组大鼠肾体比明显升高且一直维持在较高水平（P＜0.05）,造模时间越长,模型大鼠血清Scr和BUN水平及肾组织Hyp含量水平逐渐升高,与假手术组相比均具有显著差异（P＜0.05）。结论：与假手术组大鼠相比,UUO模型组大鼠肾组织中的线粒体更活跃,线粒体基因、再生基因、断裂基因和融合基因含量升高,COX含量升高,SOD含量降低,RIF指数升高,肾体比、血清Scr和BUN和肾组织Hyp水平显著升高。     

Prevention of brick tea fluorosis in rats with low-fluoride brick tea on laboratory observation.

To test whether low-fluoride brick tea can prevent the occurrence of fluorosis, rats had access only to a specially prepared low-fluoride brick tea for 1 year. The daily fluoride intake, fluoride metabolism, tissue distribution and development of tooth fluorosis were observed at 4-monthly intervals, at the end of months 4, 8 and 12, respectively. Rats drinking ordinary brick tea (F- 503.5 mg/kg) served as control. The daily intake of fluoride in the ordinary brick tea group was 0.3 mg, and this group developed dental fluorosis characterized as brown and white horizontal marks at the end of month 8, and white chalky dental fluorosis developed at the end of month 12. The total incidence was 75%. In contrast, the daily fluoride intake of the low-fluoride brick tea (F- 210 mg/kg) group was 0.19 mg, and this group did not develop any signs of dental fluorosis. Fluoride distribution was mainly retained in the bone tissue, and about half of the absorbed fluoride was excreted via urine and feces. The results suggest that this low-fluoride brick tea did not induce fluorosis in rats and can be used as an effective control measure for humans.     

The dose-time effects of fluoride on the expression and DNA methylation level of the promoter region of BMP-2 and BMP-7 in rats

Skeletal fluorosis is a chronic metabolic bone disease caused by excessive exposed to fluoride. Recent studies have shown that fluoride causes abnormal bone metabolism through disrupting the expression of Bone Morphogenetic Proteins (BMPs). However, the relationship between fluoride and BMPs is not fully understood, and the mechanism of fluoride on BMPs expression is still unclear. This study investigated the dose-time effects of fluoride on BMP-2 and BMP-7 levels and DNA methylation status of the promoter regions of these two genes in peripheral blood of rats. Eighty Wistar male rats were randomly divided into four groups and treated for 1 month and 3 months with distilled water (control), 25 mg/L, 50 mg/L or 100 mg/L of sodium fluoride (NaF). Rats exposed to fluoride had higher protein expression of BMP-2 and BMP-7 in plasma at 1 month and 3 months. An increase in BMP-2 expression was also observed with an increase of fluoride exposure time. Significant hypomethylation was observed in 2 CpG sites (CpGs) of BMP-2 and 1 CpG site of BMP-7 promoter regions in the fluoride treatment groups. It concludes that fluoride has a dose-response effect on BMP-2 in fluorosis rats, and fluoride-induced hypomethylation of specific CpGs may play an essential role in the regulation of BMP-2 and BMP-7 expression in rats.     

Defective mitochondrial function and motility due to mitofusin 1 overexpression in insulin secreting cells

Mitochondrial dynamics and distribution is critical for their role in bioenergetics and cell survival. We investigated the consequence of altered fission/fusion on mitochondrial function and motility in INS-1E rat clonal β-cells. Adenoviruses were used to induce doxycycline-dependent expression of wild type (WT-Mfn1) or a dominant negative mitofusin 1 mutant (DN-Mfn1). Mitochondrial morphology and motility were analyzed by monitoring mitochondrially-targeted red fluorescent protein. Adenovirus-driven overexpression of WT-Mfn1 elicited severe aggregation of mitochondria, preventing them from reaching peripheral near plasma membrane areas of the cell. Overexpression of DN-Mfn1 resulted in fragmented mitochondria with widespread cytosolic distribution. WT-Mfn1 overexpression impaired mitochondrial function as glucose- and oligomycin-induced mitochondrial hyperpolarization were markedly reduced. Viability of the INS-1E cells, however, was not affected. Mitochondrial motility was significantly reduced in WT-Mfn1 overexpressing cells. Conversely, fragmented mitochondria in DN-Mfn1 overexpressing cells showed more vigorous movement than mitochondria in control cells. Movement of these mitochondria was also less microtubule-dependent. These results suggest that Mfn1-induced hyperfusion leads to mitochondrial dysfunction and hypomotility, which may explain impaired metabolism-secretion coupling in insulin-releasing cells overexpressing Mfn1.     

Second generation antipsychotic-induced mitochondrial alterations: Implications for increased risk of metabolic syndrome in patients with schizophrenia

Metabolic syndrome (MetS) is seen more frequently in persons with schizophrenia than in the general population, and these metabolic abnormalities are further aggravated by second generation antipsychotic (SGA) drugs. Although the underlying mechanisms responsible for the increased prevalence of MetS among patients under SGA treatment are not well understood, alterations in mitochondria function have been implicated. We performed a comprehensive evaluation of the role of mitochondrial dysfunction in the pathophysiology of drug-induced MetS in schizophrenia. We found a downregulation in genes encoding subunits of the electron transport chain complexes (ETC), enzyme activity, and mitochondrial dynamics in peripheral blood cells from patients at high-risk for MetS. Additionally, we evaluated several markers of energy metabolism in lymphoblastoid cell lines from patients with schizophrenia and controls following exposure to antipsychotics. We found that the high-risk drugs clozapine and olanzapine induced a general down-regulation of genes involved in the ETC, as well as decreased activities of the corresponding enzymes, ATP levels and a significant decrease in all the functional parameters of mitochondrial oxygen consumption in cells from patients and controls. We also observed that the medium-risk SGA quetiapine decreased oxygen consumption and respiratory control ratio in controls and patients. Additionally, clozapine and olanzapine induced a downregulation of Drp1 and Mfn2 both in terms of mRNA and protein levels. Together, these data suggest that an intrinsic defect in multiple components of oxidative metabolism may contribute to the increased prevalence of MetS in patients under treatment with SGAs known to cause risk for MetS.     

Antioxidant defense system and lipid peroxidation in patients with skeletal fluorosis and in fluoride-intoxicated rabbits.

Fluorosis is a serious public health problem in many parts of the world where drinking water contains more than 1 ppm of fluoride. The main manifestations of skeletal fluorosis are crippling bone deformities, spinal compressions, and restricted movements of joints. Although fluorosis is irreversible, it could be prevented by appropriate and timely intervention through understanding the process at biochemical and molecular levels. As in the case of many chronic degenerative diseases, increased production of reactive oxygen species (ROS) and lipid peroxidation has been considered to play an important role, even in the pathogenesis of chronic fluoride toxicity. However, there is inconclusive proof for an altered oxidative stress and antioxidant balance in fluorosis, and the existing data are not only conflicting but also contradictory. In the present communication we have evaluated the antioxidant defense system (both enzymatic and nonenzymatic) and lipid peroxidation in both humans from an endemic fluorosis area (5 ppm fluoride in the drinking water) and in rabbits receiving water with 150 ppm of fluoride for six months. There was no significant difference in lipid peroxidation, glutathione, and vitamin C in the blood of human fluorotic patients and fluoride-intoxicated rabbits as compared to respective controls. Neither were there any changes in the activities of catalase, superoxide dismutase, glutathione peroxidase, or glutathione S-transferase in the blood due to fluoride intoxication (of rabbits) or fluorosis in humans. The results together do not subscribe to oxidative stress theory in fluorosis. Thus, in the absence of clear proof of oxidative damage and to counter toxic effects of fluoride through supplementation of antioxidants, extensive investigations are needed to conclusively prove the role of oxidative stress in skeletal fluorosis.     

Drp1-dependent mitochondrial fission in cardiovascular disease

Mitochondria are highly dynamic organelles undergoing cycles of fusion and fission to modulate their morphology, distribution, and function, which are referred as ‘mitochondrial dynamics’. Dynamin-related protein 1 (Drp1) is known as the major pro-fission protein whose activity is tightly regulated to clear the damaged mitochondria via mitophagy, ensuring a strict control over the intricate process of cellular and organ dynamics in heart. Various posttranslational modifications (PTMs) of Drp1 have been identified including phosphorylation, SUMOylation, palmitoylation, ubiquitination, S-nitrosylation, and O-GlcNAcylation, which implicate a role in the regulation of mitochondrial dynamics. An intact mitochondrial homeostasis is critical for heart to fuel contractile function and cardiomyocyte metabolism, while defects in mitochondrial dynamics constitute an essential part of the pathophysiology underlying various cardiovascular diseases (CVDs). In this review, we summarize current knowledge on the critical role of Drp1 in the pathogenesis of CVDs including endothelial dysfunction, smooth muscle remodeling, cardiac hypertrophy, pulmonary arterial hypertension, myocardial ischemia–reperfusion, and myocardial infarction. We also highlight how the targeting of Drp1 could potentially contribute to CVDs treatments.     

The absorption and excretion of fluoride and arsenic in humans

The absorption and excretion of fluoride and arsenic were measured in a group of healthy volunteers given drinking water with naturally high concentration of fluoride (F 2.3 mg/l)(,) or high concentration of arsenic (As 0.15 mg/l), or high concentrations of both fluoride and arsenic (F 2.25 mg/l, As 0.23 mg/l and F 4.05 mg/l, As 0.58 mg/l), respectively. The results indicated that, for arsenic, the absorption rate, the proportion of urinary excretion and the biological-half-life did not show statistically significant differences between drinking water containing high arsenic alone and drinking water containing different levels of high arsenic and fluoride. Excretion and retention of arsenic were positively correlated to the total arsenic intake. Similar results were observed for fluoride. This suggests that there are different metabolic processes for arsenic and fluoride in respect to absorption and excretion; and no joint action can be attributed by these two elements.     

Characterization of mitophagy in the 6-hydoxydopamine Parkinson's disease model

In the present study, the activation of autophagy and its interaction with the mitochondrial fission machinery was investigated in an experimental model of Parkinson's disease. The addition of 50μM 6-hydroxydopamine (6-OHDA) to the dopaminergic cell line SH-SY5Y profoundly stimulated formation of autophagosomes within 12h. Under these conditions, mitochondrial fission was also activated in a sustained manner, but this occurred at earlier time points (after 3h). Upon 6-OHDA treatment, dynamin-related protein 1 (Drp1) transiently translocated to mitochondria, with increased levels of mitochondrial Drp1 being observed after 3 and 9h. Pharmacological inhibition of Drp1, through treatment with the mitochondrial-division inhibitor-1 (mdivi-1), resulted in the abrogation of mitochondrial fission and in a decrease of the number of autophagic cells. In addition, 6-OHDA failed to induce the expression of the proapoptotic protein Bax in total cellular extracts although it did induce its migration to mitochondria. In our model, Bax migrated later than Drp1. However, Drp1 inhibition did not block Bax migration. These results show that reactive oxygen species but not quinone derivates act as mediators of autophagy at an early stage of the process. 6-OHDA induces hydrogen peroxide production, which was placed upstream of mitochondrial fission, given that mdivi-1 did not abrogate this increase. Furthermore, the 6-OHDA-induced activation of autophagy was also suppressed by addition of the free radical scavengers TEMPOL and MnTBAP. This effect could be reproduced by the addition of hydrogen peroxide, but not with aged 6-OHDA. To our knowledge, this is the first detailed study highlighting the various mediators that are implicated in mitochondrial alterations and autophagy of cells in response to 6-OHDA.     

一氧化碳对脂多糖诱导大鼠肺巨噬细胞损伤的影响

摘要： 目的 探讨一氧化碳（CO）对脂多糖（LPS）诱导大鼠肺巨噬细胞损伤的影响及可能机制。方法 用含有10%胎牛血清的细胞培养基, 在 37 ℃、 5%CO2细胞培养孵箱内培养大鼠肺巨噬细胞, 采用随机数字表法将其分为 4组（n=10）： 空白对照组（C 组）、 CO 组、 LPS 组、 LPS+CO 组。CO 组加入体外一氧化碳释放分子-2（CORM-2） 100μmol/L 孵育, LPS 组加入 LPS 10 mg/L, LPS+CO 组加入 CORM-2 100 μmol/L 预处理 1 h 后加入 LPS 10 mg/L 孵育, C组加入等量 PBS 液作为对照。每组细胞处理完毕后继续孵育 24 h, 采用 MTT 法测定细胞活力; 流式细胞仪测定细胞凋亡率和线粒体膜电位; ATP 酶含量试剂盒测定细胞内 ATP 含量; RT-PCR 法测定细胞中线粒体分裂相关蛋白Drp1 的 mRNA 含量; Western blot 法测定 Drp1 的蛋白表达。结果 与 C 组相比, LPS 组和 LPS+CO 组细胞活力、 ATP含量和线粒体膜电位下降, 细胞凋亡率、 线粒体分裂蛋白 Drp1 mRNA 及蛋白表达增加 （P < 0.05）, CO 组上述指标比较差异无统计学意义; 与 LPS 组比较, LPS+CO 组细胞活力、 ATP 含量和线粒体膜电位增加 （P < 0.05）, 细胞凋亡率、Drp1 mRNA 及蛋白表达减少（P < 0.05）。结论 CO 可减轻 LPS 诱导的大鼠肺巨噬细胞损伤, 其机制与下调线粒体分裂相关蛋白 Drp1 和改善线粒体功能有关。     

瑞舒伐他汀通过调控UCP2-SIRT3通路减轻脑缺血/再灌注对神经元线粒体的损伤

目的探讨瑞舒伐他汀(rosuvastatin,RS)通过UCP2-SIRT3信号通路在脑缺血/再灌注(CIR)神经元线粒体损伤中的作用及其机制。方法建立SH-SY5Y细胞的脑梗死再灌注模型(OGD/R),给予不同浓度RS(40和2.5μmol·L^-1)分别处理,观察两组中细胞增殖和凋亡的变化及UCP2和SIRT3分子的表达;构建UCP2沉默细胞系,研究不同浓度RS对UCP2沉默前后细胞形态和线粒体膜电位的影响、以及SIRT3分子、线粒体外膜异位酶20(TOMM20)和线粒体合成相关蛋白(Drp1、Opa1和PGC1)的表达变化。结果RS能提高OGD/R细胞的存活率、抑制细胞凋亡、改变细胞形态、稳定细胞线粒体膜电位;增加OGD/R细胞中UCP2、SIRT3分子和TOMM20蛋白表达,并诱导Drp1和Opa1 mRNA的表达,抑制PGC1 mRNA的表达;沉默UCP2后能明显降低OGD/R细胞的存活率及TOMM20蛋白的表达,降低Drp1和Opa1 mRNA的表达,使PGC1 mRNA的表达增加。结论RS通过调控UCP2-SIRT3通路减轻CIR对神经元线粒体的损伤,发挥神经细胞保护作用。     

Brick tea fluoride as a main source of adult fluorosis.

An epidemiological survey was conducted in Naqu County, Tibet in September 2001 to investigate the manifestations of fluorosis in adults caused by the habitual consumption of brick tea. Profiles were obtained for the total daily fluoride intake, environmental fluoride levels and average urinary fluoride concentration, and a physical examination and a skeletal radiographic study were conducted. One hundred and eleven 30-78-year-old adults were enrolled. It was found that the fluoride level of water sources in Naqu County was 0.10+/-0.03 mg/l; no evidence of fluoride air pollution was found, but the brick tea water processed foods--zamba and buttered tea--had fluoride contents of 4.52+/-0.74 mg/kg and 3.21+/-0.65 mg/l, respectively. The adult daily fluoride intake reached 12 mg, of which 99% originated from the brick tea-containing foods. The positive rate of clinical symptoms by physical examination was 89%; furthermore, 42 of the 111 subjects were diagnosed by X-ray. The positive examination rate was 83%. Although the osteosclerosis-type skeletal fluorosis (overall increased bone matrix density) affected 74%, arthropathy and arthritis affected a significant number of the patients, resulting in functional disability. The results suggest that this brick tea-type fluorosis had even more severe adverse effects on human health compared with both the water-type and coal combustion-type fluorosis that occurred in other areas of China.