[Metabonomics and its application in Chinese medicine processing].

Chinese medicine processing is a procedure to process medicinal materials under the guidance of traditional Chinese medicine(TCM) theories by using unique methods in China. The medicinal materials can only be used clinically after proper processing. With the development of the modernization of TCM, it is difficult to solve the problems in the inheritance, development, and internationalization of Chinese medicine processing. Metabonomics, a new omics technology developed at the end of the last century, is used to infer the physiological or pathological conditions of the organism with the methods such as NMR and LC-MS via investigating the changes in endogenous small molecule metabolic network after the organism is stimulated by external environment. Metabonomics coincides with the holistic view of TCM because it displays the characteristics of integrity, comprehensiveness, and dynamics, and it has been widely applied in the field of Chinese medicine processing in recent years. This study summarized the application of metabonomics in the processing mechanism and quality control of Chinese medicine processing and prospected the development of this technology in the field of Chinese medicine processing.

Structure, anti-inflammatory and anti-bacterial activities of novel pentacyclic triterpenoids and other constituents from the leaves of Pittosporum elevaticostatum.

The investigation of the leaves of Pittosporum elevaticostatum Chang et Yan led to the isolation of fifteen pentacyclic triterpenoids (1-15), including five previously undescribed ones (1-5), and nine others (16-24). The structures of compounds 1-5 were elucidated based on comprehensive spectroscopic techniques, including one dimension (1D) and 2D nuclear magnetic resonance (NMR), high resolution electrospray ionization mass spectroscopy (HR-ESI-MS), and other methods. Compounds 2 and 13 demonstrated significant inhibitory activity against Listeria monocytogenes (L. monocytogenes) with minimum inhibitory concentration (MIC) values of 32 µM. Scanning electron microscopy (SEM) observations revealed insights into the antibacterial mechanism, indicating that compounds 2 and 13 either prevent biofilm formation of dispersed the preformed cell membranes. Additionally, compounds 1, 5, 7, and 12 exhibited anti-inflammatory activity on lipopolysaccharide (LPS)-stimulated BV-2 microglial cells with IC50 values ranging from 11.27 to 17.80 µM.

A new anti-inflammatory thujane monoterpenoid glycoside ester from Pittosporum heterophyllum Franch.

Phytochemical investigation of EtOH extract of Pittosporum heterophyllum led to one new esterified thujane monoterpenoid glycoside, pitheteroside A (1), together with one eudesmane sesquiterpenoid (2) and twelve lignans (3－14). Their structures were elucidated by extensive spectroscopic analysis, including 1D and 2D NMR, ECD calculation and HRESIMS spectra. Pitheteroside A is an unreported and highly esterified monoterpenoid glycoside. All isolates were evaluated for their nitric oxide production inhibition against LPS-induced BV-2 microglial cells. Among them, compounds 1, 6 and 8 showed significant activities with IC50 values less than 10 µM. The results indicated the metabolisms from P. heterophyllum possess potential anti-inflammatory effects.

[Transport of limonin in rat intestine in situ and Caco-2 cells in vitro].

Limonin existed in citrus fruits has been shown to have anti-bacterial, anti-viral, anti-feedant, anti-nociceptive, anti-inflammatory activities and anti-carcinogenic activities. But the clinical use is limited by its low bioavailability. The aim of this study is to observe the absorption and secretion transport mechanisms of limonin in intestine which can pave the way for the further study and clinical use. The transport characteristics and mechanisms of limonin in rat were studied by in situ intestine perfusion and in vitro Caco-2 cells method. The intestinal absorption of limonin was probably via a facilitated diffusion pathway which was poor and without segment-selection. Verapamil and ketoconazole improved the absorption remarkably according to the result of in vitro Caco-2 cells study; however, probenecid had no significant effect on the absorption. The P-gp efflux and CYP3A4 metabolism were involved in the poor intestinal absorption and low bioavailability of limonin. The exploration of the intestinal absorption mechanism is crucial to the design of dosage form and clinical use of limonin.

Further sesquiterpenoids from Pittosporum qinlingense and their anti-inflammatory activity.

Four new sesquiterpenoid glycoside esters, Pitqinlingoside N-Q (1-4), together with eleven known metabolites (5-15), were isolated from 95% EtOH extract of the twigs, fruits and leaves of P. qinlingense. The structures of new compounds were elucidated on the basis of extensive spectroscopic analyses, including IR, UV, HRMS, NMR and electronic circular dichroism spectra. Unusal glycoside esters are characterized by the presence of polyacylated ß-D-fucopyranosyl and ß-d-glucopyranosyl units. Pitqinlingoside N (1), O (2), P (3), boscialin (5) and arvoside C (6) showed significant nitric oxide production inhibition in lipopolysaccharide (LPS)-induced BV-2 microglial cells with IC50 values ranging from 1.58 to 28.74 µM. Structure-activity relationships of the isolated compounds are discussed.

An overview of grayanane diterpenoids and their biological activities from the Ericaceae family in the last seven years.

Grayanane diterpenoids, possessing a unique 5/7/6/5 tetracyclic system, exist exclusively in plants of the Ericaceae family. Owing to their various skeletons, complex structures, and diverse bioactivities, grayanoids have been the topic of research in many phytochemical and pharmacological laboratories, offering opportunities for the development of new drugs with analgesic, anti-inflammatory, and protein tyrosine phosphatase 1B (PTP1B) properties. Recently, a number of new grayanane diterpenoids with unprecedented carbon skeletons have been obtained from plants of the Ericaceae family, and they exhibit diverse biological properties, such as agalgesic, antinociceptive, anticancer, antiviral, antifeedant, insecticidal, toxicity, and PTP1B. In this review, 162 new grayanoids with 14 carbon skeletons from the Ericaceae family over the past seven years (2012-October 2018) are discussed, including their occurrence and distribution, skeleton types, structural features, biological activities, and structure-activity relationships (SARs). Also, strategies for the structural elucidation are summarized to provide useful information for medicinal chemists in developing potent anticancer, antiviral, analgesic, anti-inflammatory, and novel PTP1B agents.

Creating single Majorana type topological zero mode in superfluids of cold fermionic atoms.

We explore the topological phase, which involves Majorana type topological zero mode fermions (MTZFs) at the edge, using d-wave superfluid with Rashba spin-orbit coupling (SOC) interactions. The self-Hermitian of this MTZF([Formula: see text]) is similar to that of the Majorana fermions (MFs) ([Formula: see text]). We show that, to realize a single MTZF at each edge in superfluid with d-wave pairing in a Majorana type Kramers Doublet (MTKD) state, it is important to lift both the spin and the Dirac Cones degeneracies. These non-Abelian anyons obey the non-Abelian statistics which may be useful to realize topological quantum computation. We suggest that the topological feature could be tested experimentally in superfluids of cold fermionic atoms with laser field induced spin orbit interactions. These studies give a new possible way to investigate the MTZFs in a two-dimensional (2D) system as compared to MFs in the one-dimensional (1D) nano-wire and 2D system, and enrich the theoretical research on finding non-Abelian anyons in topological system.

Insecticidal Constituents from Buddlej aalbiflora Hemsl.

Eleven known compounds, deoxymikanolide (1), 1,3-dihydroxyxanthone (2), kumatakenin (3), apigenin (4), chrysin (5), kaempferol (6), Iso-kaempferol (7), luteolin (8), luteolin-3',4'-dimethylether-7-O-ß-glucoside (9), luteolin-7-O-ß-glucoside (10) and quercetin (11) were identified in MeOH extract of Buddleja albiflora Hemsl (Oleaceae). These compounds (each, 1, 0.5 and 0.25 mg mL-1) were tested for insecticidal activity against 3rd and 4th-instar larvae of Plutella xylostella, 3rd-instar larvae of Mythimna separata and 3rd-instar larvae of Macrosiphoniella sanborni. The lowest 50% anti-feedant concentration (AFC50) against P. xylostella and 50% lethal concentration (LC50) against P. xylostella and M. sanborni were observed as 0.0058, 0.0046 and 3.4048 mg L-1, respectively.

α-Glucosidase inhibitors and phytotoxins from Streptomyces xanthophaeus.

Twenty-four metabolites 1-24 were isolated from the fermentation broth of Streptomyces xanthophaeus. Their structures were elucidated on the basis of spectroscopic analysis and by comparison of their NMR data with literature data reported. Daidzein (1), genistein (2) and gliricidin (3) inhibited α-glucosidase in vitro with IC50 values of 174.2, 36.1 and 47.4 µM, respectively, more potent than the positive control, acarbose. Docking study revealed that the amino acid residue Thr 215 is the essential binding site for active ligands 2. In addition, the phytotoxic effects of all compounds were assayed on radish seedlings, five of which, 3, 8, 13, 15 and 18, inhibited the growth of radish (Raphanus sativus) seedlings with inhibitory rates of >60% at a concentration of 100 ppm, which was comparable or superior to the positive control glyphosate. This is the first report of the phytotoxicity of the compounds.

A novel Mn(2+)-doped core/shell quantum dot-based intracellular probe for fluoride anions sensing in MC3T3-E1 osteoblastic cells.

In this paper, 3-aminobenzeneboronic acid functionalized Mn(2+)-doped ZnTe/ZnSe quantum dots (APBA-dQDs) were prepared. The APBA functional groups had strong binding ability with F(-), resulting in the quenchment of dQDs photoluminescence (PL). Under the optimal condition, the fluorescence intensity of APBA-dQDs was related linearly to the concentration of F(-) in the range of 0.25-1.5µmol/L with a detection limit of 0.1µmol/L. The selectivity of fluorescence quenching of APBA-dQDs for F(-) was enhanced. Moreover, the proposed methodology for the sensing of F(-) at EM 560nm in MC3T3-E1 osteoblastic cells was demonstrated and got a satisfactory results. The results indicate that the APBA-dQDs are promising candidates for intracellular in MC3T3-E1 osteoblastic cells. To the best of our knowledge, it was the first report of F(-) sensing by using the quenched fluorescence of APBA-dQDs in non-cancerous cells.

Mechanisms of Intracellular Calcium Homeostasis in MC3T3-E1 Cells and Bone Tissues of Sprague-Dawley Rats Exposed to Fluoride.

Calcium homeostasis of osteoblasts (OBs) has an important role in the physiology and pathology of bone tissue. In order to study the mechanisms of intracellular calcium homeostasis, MC3T3-E1 cells and Sprague-Dawley rats were treated with different concentrations of fluoride. Then, we examined intracellular-free calcium ion ([Ca(2+)]i) in MC3T3-E1 cells as well as mRNA and protein levels of Cav1.2, the main subunit of L-type voltage-dependent calcium channels (VDCCs), Na(+)/Ca(2+) exchange carriers (NCS), and plasma membrane Ca(2+)-ATPase (PMCA), inositol 1,4,5-trisphosphate receptor (IP3R) channels, sarco/endoplasmic reticulum calcium ATPase 2b (SERCA2b)/ATP2A2 in vitro, and rat bone tissues in vivo. Our results showed that [Ca(2+)]i of fluoride-treated OBs increased in a concentration-dependent manner with an increase in the concentration of fluoride. We also found that the low dose of fluoride led to high expression levels of Cav1.2, NCS-1, and PMCA and low expression levels of IP3R and SERCA2b/ATP2A2, while the high dose of fluoride induced an increase in SERCA2b/ATP2A2 levels and decrease in Cav1.2, PMCA, NCS-1, and IP3R levels. These results demonstrate that calcium channels and calcium pumps of plasma and endoplasmic reticulum (ER) membranes keep intracellular calcium homeostasis by regulating Cav1.2, NCS-1, PMCA, IP3R, and SERCA2b/ATP2A2 expression.

Proteomic analysis of kidney in fluoride-treated rat.

The recent development of proteomic techniques has enabled investigators to directly examine the population of proteins present in biological systems. We first report here the proteomic changes of renal protein induced by fluoride. To investigate molecular mechanisms of renal injury induced by fluoride, proteins were isolated from rat kidney and profiled by two-dimensional gel electrophoresis (2DE). With the analysis of Image-Master 2D Elite software, 141 up-regulated and eight down-regulated protein spots in 2DE gels of fluoride-treated group were gained by comparison to the control group, 13 of which were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The identified proteins are mainly related with cell proliferation, metabolism and oxidative stress, and provide a valuable clue to explore the mechanism of renal fluorosis. This study also shows that the proteomic techniques were powerful in fluoride toxical field.

[Differential expression of osteopontin and bax, bcl-2 by fluoride].

OBJECTIVE: To study the differential expression of bax, bcl-2 and osteopontin by fluoride in the renal tubular cells in vitro. METHODS: The renal tubular cells were cultured and exposed to sodium fluoride (NaF) in 1, 5, 7.5, 12.5 mg F-/L level. The transcription level of bax, bcl-2 and osteopontin were investigated by reverse transcription - polymerase chain reaction (RT-PCR). RESULTS: The expression of bax mRNA in 7.5 and 12.5 mgF-/L groups (optical absorption ratio value was 2.37 +/- 0.18 and 2.64 +/- 0.19 respectively) was significantly increased (P < 0.01). On the contrary, the level of bcl-2 obviously decreased (5 mg F-/L group optical absorption ratio value, 0.80 +/- 0.22, P < 0.05; 7.5 mg F-/L group optical absorption ratio value 0.71 +/- 0.22, P < 0.01). The expression mRNA of osteopontin was significantly increased when cells were exposed to fluoride at 7.5 mg F-/L (optical absorption ratio value 2.01 +/- 0.40 P < 0.01), in that group the tubular cell apoptotic trend was obvious. CONCLUSION: NaF might induce tubular cell apoptosis via activation of bax expression and bcl-2 suppression. Osteopontin might protect the tubule against apoptosis in a lower fluoride level, but the function should be decreased in higher fluoride level.

[Ameliorative effect of ginseng glycopeptide on cross-linking of rat tail tendon collagen].

OBJECTIVE: To investigate the ameliorative effect of ginseng glycopeptide on cross-linking of rat tail tendon collagen. METHOD: ELISA was used to determine the inhibitory effect of ginseng glycopeptide on cross-linking of rat tail tendon collagen in vitro. After ginseng glycopeptide was intraperitoneally administrated to streptozotocin-induced diabetic rats for 12 weeks, the acid solubility, limited pepsin degradation properties and solubility in SDS-2-mercaptoethanol of the rat tail tendon collagen were determined, and the effect of ginseng glycopeptide on the tail tendon collagen cross-linking was evaluated. RESULT: Ginseng glycopeptide inhibited significantly the cross-linking of rat tail tendon collagen in vitro. The solubility of the tail tendon collagen (in acid, pepsin and SDS-2-mercaptoethanol) was markedly decreased in diabetic rats and ginseng glycopeptide-treated diabetic rats had significantly an increase in the collagen solubility in the above-mentioned solutions, suggesting that ginseng glycopeptide decreased severity of the collagen cross-linking. CONCLUSION: Ginsengglycopeptide exhibits an significantly ameliorative effect on cross-linking of rat tail tendon collagen.

Fluoride Affects Calcium Homeostasis by Regulating Parathyroid Hormone, PTH-Related Peptide, and Calcium-Sensing Receptor Expression.

Parathyroid hormone (PTH), PTH-related peptide (PTHrP), and calcium-sensing receptor (CaSR) play important roles in maintaining calcium homeostasis. Here, we study the effect of fluoride on expression of PTH, PTHrP, and CaSR both in vitro and in vivo. MC3T3-E1 cells and Sprague-Dawley rats were treated with different concentrations of fluoride. Then, the free calcium ion concentration in cell culture supernatant and serum were measured by biochemical analyzer. The expression of PTH, PTHrP, and CaSR was analyzed by qRT-PCR and Western blot. We found that the low dose of fluoride increased ionized calcium (i[Ca(2+)]) and the high dose of fluoride decreased i[Ca(2+)] in cell culture supernatant. The low dose of fluoride inhibited the PTH and PTHrP expression in MC3T3-E1 cells. The high dose of fluoride improved the PTHrP expression in MC3T3-E1 cells. Interestingly, we found that NaF decreased serum i[Ca(2+)] in rats. Fluoride increased CaSR expression at both messenger RNA (mRNA) and protein levels in MC3T3-E1 cells and rats. The expression of PTHrP protein was inhibited by fluoride in rats fed regular diet and was increased by fluoride in rats fed low-calcium diet. Fluoride also increased the expression of PTH, NF-kappaB ligand (RANKL), and osteoprotegerin (OPG) in rats. The ratio of RANKL/OPG in rats fed low-calcium food in presence or absence of fluoride was significantly increased. These results indicated that fluoride might be able to affect calcium homeostasis by regulating PTH, PTHrP, and CaSR.

[Expression of proto-oncogenes c-fos and c-jun in osteoblasts activated by excessive fluoride].

OBJECTIVE: To study expression of proto-oncogenes c-fos and its accompanying gene c-jun in osteoblasts activated by action of excessive fluoride in vivo and in vitro. METHODS: Experimental Wistar rats were exposed to sodium fluoride (NaF) added to their drinking water, and NaF was also added in cell culture supernatant for osteoblast-like cells in vitro. Expression of both mRNA and protein of c-fos and c-jun in bone-tissue of rats with chronic fluorosis and cultured osteoblast-like cells were determined by hybridization in situ, Western blot and immunohistochemistry at varied time periods after exposure. RESULTS: Sodium fluoride could stimulate the proliferation of osteoblast in rats with chronic fluorosis and induce expression of both c-fos and c-jun in all envelops of the spine bone, as compared with its control group. Value of optical absorption in mRNA expression of c-fos and c-jun was 139.63 and 126.37, respectively, in rats with NaF plus high-calcium, significantly lower than that in control group with high-calcium only (107.74 and 117.48, respectively) (P < 0.001). Immunohistochemical analysis showed that protein level of c-fos and c-jun was significantly higher in rats with NaF plus high-calcium than that in control rats with high-calcium only, with values of optical absorption of 139.16, 131.15, 149.98 and 149.19 (P < 0.05), respectively, and protein level of c-fos and c-jun was significantly higher in rats with NaF plus low-calcium than that in control rats with low-calcium only, with values of optical absorption of 117.24, 111.46, 132.46 and 129.79 (P < 0.05), respectively. Western blotting showed that level of protein expression of c-fos and c-jun in periosteal osteoblasts was significantly higher in all rat groups with NaF than that in all control groups, with values of optical absorption of 123.32, 116.60, 115.97 and 108.30, respectively. mRNA expression of c-fos and c-jun in osteoblast-like cells treated with NaF for 12 h increased obviously, and remained at high level 48 h after exposure, with values of optical absorption of 114.80, 161.14, 118.20, and 150.41, respectively, as compared with that in control group (P < 0.001 and P < 0.05). CONCLUSIONS: Exposure to excessive fluoride could stimulate activation and proliferation of both osteoblasts in rats and cultured osteoblast-like cells in vitro, and cause enhanced expression of mRNA and protein of both c-fos and c-jun. Over-expression of c-fos could play an important role in development and proliferation of skeletal lesions in rats with chronic fluorosis.

Fluoride affects calcium homeostasis and osteogenic transcription factor expressions through L-type calcium channels in osteoblast cell line.

Osteoblast L-type voltage-dependent calcium channels (VDCC) play important roles in maintaining intracellular homeostasis and influencing multiple cellular processes. In particular, they contribute to the activities and functions of osteoblasts (OBs). In order to study how L-type VDCC modulate calcium ion (Ca(2+)) homeostasis and the expression of osteogenic transcription factors in OBs exposed to fluoride, MC3T3-E1 cells were exposed to a gradient of concentrations of fluoride (0, 2.0, 5.0, 10.0 mg/L) in combination with 10 µM nifedipine, a specific inhibitor of VDCC, for 48 h. We examined messenger RNA (mRNA) and protein levels of Cav1.2, the main subunit of VDCC, and c-fos, c-jun, runt-related transcription factor 2 (Runx2), osterix (OSX), and intracellular free Ca(2+) ([Ca(2+)]i) concentrations in MC3T3-E1 cells. Our results showed that [Ca(2+)]i levels increased in a dose-dependent manner with increase in concentration of fluoride. Meantime, results indicated that lower concentrations of fluoride (less than 5 mg/L, especially 2 mg/L) can lead to high expression of Cav1.2 and enhance osteogenic function, while high concentration of fluoride (10 mg/L) can induce decreased Cav1.2 and osteogenic transcriptional factors in MC3T3E1 cells exposed to fluoride. However, the levels of [Ca(2+)]i, Cav1.2, c-fos, c-jun, Runx2, and OSX induced by fluoride were significantly altered and even reversed in the presence of nifedipine. These results demonstrate that L-type calcium channels play a crucial role in Ca(2+) homeostasis and they affect the expression of osteogenic transcription factors in fluoride-treated osteoblasts.

[Effects of filamentous macroalgae on the methane emission from urban river: a review].

The global warming caused by greenhouse gases emission has raised serious concerns. Recent studies found that the carbon dioxide (CO2) and methane (CH4) emissions from river ecosystem can partly offset the carbon sequestration by terrestrial ecosystem, leading to a rethink of the effects of river ecosystem on the global carbon balance and greenhouse gases emission inventory. As an important primary producer in urban river ecosystem, filamentous macroalgae can deeply affect the carbon cycle process of river system through changing the abiotic and biotic factors in the interface of water-sediment. This paper reviewed the effects of filamentous macroalgae on the CH4 emission from urban river system from the aspects of 1) the effects of urbanization on the river ecosystem and its CH4 emission flux, 2) the effects of filamentous macroalgae on the CH4 generation and emission process in natural river systems, and 3) the effects of filamentous macroalgae on the primary productivity and CH4 emission process in urban river systems. The current problems and future directions in related researches were discussed and prospected.

[Effects of climate warming on oil flax growth and water use efficiency in semi-arid region of Loess Plateau, Northwest China].

By using the site-specific observation data of oil flax growth and related meteorological records in semi-arid region of Loess Plateau, this paper studied the effects of climate change on the oil flax growth, and analyzed the relationships between the oil flax water use efficiency and meteorological condition. In this region, the annual precipitation displayed a decreasing trend, and its climatic trend rate was -15.80 mm (10 a)(-1), with an annual periodic change of 3 a and 6 a, whereas the annual air temperature had an increasing trend, and its climatic trend rate was 0.36 degrees C (10 a)(-1). In crop growth period, the aridity index displayed a marked increasing trend, its climatic trend rate was 0.12 (10 a)(-1), and the aridity tendency was more obvious from the beginning of 1990s to the year 2009. From sowing to maturation, oil flax needed 120-150 d, 1700-2100 degrees C d of > or = 0 degrees C accumulated temperature, 200-250 mm precipitation, and 1000-1300 h sunshine hours. The main meteorological factors affecting the oil flax growth in the region were air temperature and precipitation. The increase of air temperature shortened the prophase vegetative growth stage, whereas the increase of air temperature and the decrease of precipitation extended the reproductive growth stage, causing the extension of the whole growth period of the oil flax. The air temperature in the oil flax whole growth period except at seeding stage and maturing stage had negative effect on the yield formation, being more obvious at squaring stage, whereas the precipitation in the whole growth period except at blooming stage had positive effect on the yield formation, being more obvious at seeding stage. The water use efficiency of the oil flax was significantly positively correlated with the air temperature and sunshine hours at seeding stage as well as the aridity index from squaring stage to maturing stage, and negatively correlated with the precipitation from squaring stage to maturing stage. In the study region, the aridity index from May to July was the key factor affecting the water use efficiency of oil flax.

Activation of PERK signaling through fluoride-mediated endoplasmic reticulum stress in OS732 cells.

Our proteomical analysis of osteoblasts exposed to fluoride revealed a distinctive upregulation of proteins in osteoblast. These upregulated proteins play key roles in the protein folding. The PRK-like ER kinase (PERK) signaling, one branch of unfolded protein response (UPR) to combat ER stress, is a transcription factor needed for osteoblast proliferation and differentiation. The mechanism of skeletal fluorosis by which fluoride regulates osteoblast is not fully defined. Here we studied the effect of fluoride on PERK signaling genes and x-box binding protein 1 (xbp-1) in OS7232 cells (human osteoblast-like cell line). Meantime, genes associated with bone turnover were examined in this study. We found that early and continuous fluoride exposure increased the binding immunoglobulin protein (BiP) expression and activated the PERK signaling pathway, resulting in activation of transcription factor 4 (ATF4) and nuclear factor erythroid 2-related factor 2 (Nrf2). The altered expression of cbfa1, osteoprotegerin (OPG)/nuclear factor kappa B ligand (RANKL) were viewed in this study. These results showed fluoride impelled a distinctive ER stress response in OS732 cells, primarily by activating PERK and PERK-dependent signaling. Little effects were viewed for activating xbp-1, a common target of the other two canonical sensors of ER stress, ATF6 and IRE1. In this study the altered expression of bone turnover genes were consistent with activation of ER stress and PERK signaling. This study proved that PERK signaling play major roles in action of fluoride on osteoblast, and suggested that bone response in skeletal fluorosis may be due in part to PERK signaling pathway.