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OBJECTIVES@#Hypoxia can alter the oral bioavailability of drugs, including various substrates (drugs) of P-glycoprotein (P-gp), suggesting that hypoxia may affect the function of P-gp in intestinal epithelial cells. Currently, Caco-2 monolayer model is the classic model for studying the function of intestinal epithelial P-gp. This study combines the Caco-2 monolayer model with hypoxia to investigate the effects of hypoxia on the expression and function of P-gp in Caco-2 cells, which helps to elucidate the mechanism of changes in drug transport on intestinal epithelial cells in high-altitude hypoxia environment.@*METHODS@#Normally cultured Caco-2 cells were cultured in 1% oxygen concentration for 24, 48, and 72 h, respectively. After the extraction of the membrane proteins, the levels of P-gp were measured by Western blotting. The hypoxia time, with the most significant change of P-gp expression, was selected as the subsequent study condition. After culturing Caco-2 cells in transwell cells for 21 days and establishing a Caco-2 monolayer model, they were divided into a normoxic control group and a hypoxic group. The normoxic control group was continuously cultured in normal condition for 72 h, while the hypoxic group was incubated for 72 h in 1% oxygen concentration. The integrity and polarability of Caco-2 cells monolayer were evaluated by transepithelial electrical resistance (TEER), apparent permeability (Papp) of lucifer yellow, the activity of alkaline phosphatase (AKP), and microvilli morphology and tight junction structure under transmission electron microscope. Then, the Papp of rhodamine 123 (Rh123), a kind of P-gp specific substrate, was detected and the efflux rate was calculated. The Caco-2 cell monolayer, culturing at plastic flasks, was incubated for 72 h in 1% oxygen concentration, the expression level of P-gp was detected.@*RESULTS@#P-gp was decreased in Caco-2 cells with 1% oxygen concentration, especially the duration of 72 h (P<0.01). In hypoxic group, the TEER of monolayer was more than 400 Ω·cm2, the Papp of lucifer yellow was less than 5×10-7 cm/s, and the ratio of AKP activity between apical side and basal side was greater than 3. The establishment of Caco-2 monolayer model was successful, and hypoxia treatment did not affect the integrity and polarization state of the model. Compared with the normoxic control group, the efflux rate of Rh123 was significantly reduced in Caco-2 cell monolayer of the hypoxic group (P<0.01). Hypoxia reduced the expression of P-gp in Caco-2 cell monolayer (P<0.01).@*CONCLUSIONS@#Hypoxia inhibits P-gp function in Caco-2 cells, which may be related to the decreased P-gp level.
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Humans , ATP Binding Cassette Transporter, Subfamily B, Member 1 , Caco-2 Cells , ATP Binding Cassette Transporter, Subfamily B , Hypoxia , OxygenABSTRACT
ObjectiveTo verify the anti-oxidative stress effect of Huangqintang based on the nuclear factor E2-related factor 2 （Nrf2） signaling pathway by using Caco-2 cells as a carrier and RNA interference （RNAi） technology with in vitro experiments. MethodThe Caco-2 cells in the logarithmic growth phase were transfected with siRNA to construct siRNA Caco-2 cells. After normal Caco-2 cells and siRNA Caco-2 cells were incubated with Huangqintang of different doses， RNA and protein were extracted. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot were used to detect the mRNA and protein expression of heme oxygenase-1 （HO-1）， NAD（P）H quinone oxidoreductase 1 （NQO1）， glutathione S-transferase （GST）， Kelch-like ECH-associated protein 1 （Keap1）， and Nrf2. Meanwhile， the activities of superoxide dismutase （SOD） and GSH-Px， as well as the expression levels of malondialdehyde （MDA） and reactive oxygen species （ROS）， were detected by the colorimetric method and the probe method. ResultCompared with the results in the normal group， only the 400 mg·L-1 Huangqintang group and the sulforaphane （SFN） group could reduce the content of ROS and MDA in Caco-2 cells （P<0.01）， while the activities of SOD and GSH-Px in the cells of the Huangqintang groups and the SFN group showed an upward trend. Furthermore， there were significant differences in the 400 mg·L-1 Huangqintang group/the SFN group and the normal group （P<0.01）. Meanwhile， the protein and mRNA expression levels of HO-1， GST， Keap1， NQO1， and Nrf2 showed an upward trend in all groups （P<0.05， P<0.01）. After transfection， compared with the normal group， the model group showed increased content of MDA and ROS， blunted activities of GSH-Px and SOD， and reduced protein and mRNA expression of HO-1， GST， Keap1， and NQO1 （P<0.05， P<0.01）. After drug incubation， compared with the model group， the SFN group showed potentiated SOD activity， and the SFN group and the Huangqintang groups showed enhanced GSH-Px activity （P<0.01）. Moreover， the activities of SOD and GSH-Px in the 400 and 200 mg·L-1 Huangqintang groups and the SFN group showed an upward trend （P<0.01）， and the content of MDA in the 400 mg·L-1 Huangqintang group and the SFN group showed a downward trend. ROS decreased in all groups with drug intervention （P<0.01）， and the protein and mRNA expression of HO-1， GST， Keap1， NQO1， and Nrf2 increased to varying degrees （P<0.05， P<0.01）. ConclusionHuangqintang can play an anti-oxidative stress role by regulating the Nrf2 pathway.
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Saikosaponins (SSs) are the main active components extracted from Bupleuri Radix (BR) which has been used as an important herbal drug in Asian countries for thousands of years.It has been reported that the intestinal bacteria plays an important role in the in vivo disposal of oral SSs.Although the deglycosylated derivatives (saikogenins,SGs) of SSs metabolized by the intestinal bacteria are speculated to be the main components absorbed into the blood after oral administration of SSs,no studies have been reported on the characteristics of SGs for their intestinal absorption,and those for SSs are also limited.Therefore,a rapid UHPLC-MS/MS method was developed to investigate and compare the apparent permeability of three common SSs (SSa,SSd,SSb2) and their corresponding SGs (SGF,SGG,SGD) through a bidirectional transport experiment on Caco-2 cell monolayer model.The method was validated according to the latest FDA guidelines and applied to quantify the six analytes in transport medium samples extracted via liquid-liquid extraction (LLE).The apparent permeability coefficient (Papp) determined in this study indicated that the permeability of SGs improved to the moderate class compared to the corresponding parent compounds,predicting a higher in vivo absorption.Moreover,the efflux ratio (ER) value demonstrated an active uptake of SSd and the three SGs,while a passive diffusion of SSa and SSb2.
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Objective: To prepare the taxifolin and determine its apparent oil-water partition coefficient in different media, and to study the mechanism of absorption and transport of taxifolin in Caco-2 cell model. Methods: Taxifolin was prepared by enzymolysis. HPLC was used to determine the saturated solubility of taxifolin in 37 ℃, different pH buffer solution and water, apparent oil-water distribution coefficient of taxifolin obtained by calculation formula of oil-water distribution coefficient; CCK-8 experiment was used to investigate the safe concentration range of taxifolin in Caco-2 cells, and then the single-layer model of Caco-2 cells was used to study the mechanism of bilateral transmembrane absorption and transport. CCK-8 experiment was used to investigate the safe concentration range of taxifolin in HDMEC cells. The inflammatory model of HDMEC cells induced by lipopolysaccharide was established, and the activity of lactic dehydrogenase was detected by the intervention of floxacin. The activity of lactic dehydrogenase was detected by lactic dehydrogenase kit. Results: The lgP values of taxifolin in the following solvents were 0.29 (0.1 mol/L hydrochloric acid), 0.48 (pH 2.0), 0.46 (pH 5.8), 0.34 (pH 6.8), 0.26 (pH 7.4), and 0.38 (water), respectively; There was no significant toxic effect on Caco-2 cells in the range of 50-500 μg/mL; There was no significant difference in Papp value of bilateral transport between different concentrations of taxifolin in Caco-2 monolayer cell model, and it was less than 1 × 10-6 cm/s and ER was less than 2. There was no significant toxic effect on HDMEC cells in the range of 50-300 μg/mL; After treatment with taxifolin, compared with LPS stimulation group, the activity of LDH in each treatment group was decreased significantly (P < 0.05), and the activity of LDH was decreased significantly in the range of 50-100 μg/mL, and tended to be stable in the range of 100-250 μg/mL. Conclusion: Taxifolin is a kind of drug which is difficult to absorb in the intestine. The mechanism of transmembrane transport is passive transport. It can inhibit the inflammation of hdmec cells induced by LPS and has anti-inflammatory activity.
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To study the biopharmaceutics characteristics of paris saponin VII (PSVII). The solubility of PSVII was evaluated by measurement of the equilibrium solubility in different solvents and media. The permeability of PSVII was evaluated by measuring the oil/water partition coefficient (lgP) and determining the apparent permeability coefficient (PC) on a mono-layer Caco-2 cell model. The effects of p-glycoprotein and multidrug resistance related protein 2 on PSVII transport in mono-layer Caco-2 cell model were further investigated. Finally, the small intestinal absorption of PSVII was investigated in rat. In solvents of different pH, the equilibrium solubility of PSVII was quite low, and the dose number of PSVII was larger than 1. The lgP of PSVII was less than 0. The apparent permeability coefficient [PC] of PSVII in mono-layer Caco-2 cell model was less than 14.96 × 10 cm·s, and the efflux ratio of PSVII in mono-layer Caco-2 cell model was less than 1. The transport rate of PSVII in mono-layer Caco-2 cell model was not affected by the inhibitors of p-glycoprotein and multidrug resistance related protein 2. After oral administration, PSVII could be detected in rat intestinal contents, but could not be detected in the small intestinal mucosa. PSVII showed low solubility and permeability, which would result in low oral bioavailability in clinic. PSVII belonged to Class IV compound in biopharmaceutics classification system.
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Wutou-Gancao herb-pair is extensively used to attenuate the toxicity and enhance the efficacy of aconite. In this study, potential synergic mechanism of the herb pair was investigated by utilizing multiple ap-proaches. In silico and in vitro Caco-2 cell models were applied to study the potential binding mode of bioactive ingredients existing in liquorice with P-glycoprotein (P-gp), as well as the inhibition effects on P-gp. Additionally, anti-inflammatory activity of aconitine (AC) combined with active ingredients of liquorice, as well as pharmacokinetic patterns of AC after co-administration was investigated. Anti-inflammatory effect of AC (1 mg/kg) in rats was enhanced in combination with bioactive ingredients of liquorice (10 mg/kg). In the meanwhile, the exposure of AC in vivo was altered, in terms of Cmax and AUC. For instance, the Cmax and AUC were increased to 1.9 and 1.3 folds, respectively, when used in combination with liquiritigenin. The in silico study revealed the potential binding mode with outward facing conformation of P-gp. The resulting data obtained from transport of rhodamine-123 (Rh-123) across Caco-2 cell monolayer further indicated that the function of P-gp was inhibited by chemicals in liquorice. The synergic effect was therefore proposed to be attributed to inhibition of P-gp by liquorice since AC has been demonstrated to be the substrate of P-gp. The resuls revealed that potential synergic mechanism of Wutou-Gancao herb-pair by inhibiting function of key efflux transporter P-gp to enhance the exposure of AC in systematic circulation, and further the anti-inflammatory effect, which helps clarify the compatibility rationale of these two herbs.
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Objective: To investigate transport mechanism of cyperotundone in Caco-2 cell model and provide experimental basis for clinical application of Cyperi Rhizoma. Method: The toxicity of cyperotundone with different concentrations to Caco-2 cells was investigated by methyl thiazolyl tetrazolium (MTT) colorimetry, in order to determine the concentration of administration in transport test. The content of cyperotundone was determined by liquid chromatography-mass spectrometry (LC-MS) with apparent permeability coefficient (Papp) and cumulative transport capacity as indexes. The chromatographic conditions were as following:mobile phase of acetonitrile (A)-water (B) for gradient elution (0-1.5 min, 35%A; 1.5-2 min, 35%-90%A; 2-4 min, 90%A; 4-4.1, 90%-35%A; 4.1-8 min, 35%A), the flow rate at 0.3 mL · min-1, injection volume of 1 μL, and temperature of column at 30℃. The mass spectrometric conditions was electrospray ionization (ESI) and positive ion mode, the detection ions of cyperotundone and osthole (internal standard substance) were m/z 219.2-110.9 and m/z 245.0-189.0, respectively. Effect of concentration of cyperotundone, administration time, ethylenediamine tetraacetic acid (EDTA) and P-glycoprotein (P-gp) inhibitor on the transmembrane transport of cyperotundone on in vitro cell model were investigated. Result: Cyperotundone didn't have significant toxicity to Caco-2 cells at 3-90 mg · L-1 after incubation for 4 h. The transportion of cyperotundone in Caco-2 cell model was related to the concentration and time to a certain extent, its Papp was higher than 1×10-6 cm · s-1, which indicated that absorption of cyperotundone was good, the efflux rate (ER) of cyperotundone was 0.5-1.5.There was no significant difference in bidirectional Papp of cyperotundone after the addition of cell bypass transport inhibitor (EDTA) and P-gp transport inhibitor (verapamil). Conclusion: The transport mechanism of cyperotundone in Caco-2 cell model is mainly passive diffusion, and cell bypass transport and P-gp are not involved in its transport.
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Twenty-one protostane-type triterpenoids with diverse structures, including nine new compounds (-), were isolated from the of Linn. Structurally, alisolides A‒F (-), composed of an oxole group coupled to a five-membered ring, represent unusual C-17 spirost protostane-type triterpenoids. Alisolide H () is a novel triterpenoid with an unreported endoperoxide bridge. Alisolide I () represents the first example of 23,24-acetal triterpenoid. Their structures were elucidated based on spectroscopic analysis, wherein the absolute configurations of ‒, were further confirmed by the Mo(OAc)-induced ECD method. Furthermore, all isolates were evaluated for their inhibitory effects on LPS-induced NO production in Caco-2 cells, and all the compounds showed remarkable inhibitory activities, with IC values in the range of 0.76-38.20 μmol/L.
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OBJECTIVE: To study the effects of three aconitine transporters in Caco-2 cells and tannin (tannic acid) in Terminalia on the transport of three di-ester aconitine (aconitine, meoaconitine and hypaconitine) in Aconitum chinensis. METHODS: The components were detected by UPLC/Q exactive MS in terms of the cumulative transshipment volume of three aconitine and the apparent permeability coefficient Papp as indicators to investigate the two-way transport behaviors of three aconitine in the Caco-2 cell model, as well as the proportion of tannic acid, and the changes of the transport behaviors of three aconitine. RESULTS: There was a positive correlation between the cumulative transshipment volume of aconitine and the incubation time. There was no statistical difference in Papp values of the three aconitine, and the efflux effect was significantly stronger than the absorption, with an external ratio close to 1.5.When the compatibility ratio of three aconitine with tannic acid was 1∶1 and 1∶0.5, the absorption of aconitine was significantly inhibited (P was 0.05), but the transport behavior with effluent was not significantly affected. CONCLUSION: Aconitine, meoaconitine, and hypaconitine in P. aeruginosa are mainly passive transporters, and may involve in efferent proteins, which are a kind of drug with good absorption.When mixed with tannic acid, the absorption and transshipment of three kinds of alkali were significantly reduced, which proves that Terminalia chebula could detoxify aconitum by inhibiting its absorption.
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Objective To study the uptake property of apigenin in Caco-2 cells.Methods Caco-2 cell monolayer model was used to research the effects of apigenin on cell uptake in different times, concentrations, temperatures, pH values, and P-gp inhibitors. HPLC was used to determine the content of apigenin in cells.Results The linearity of apigenin concentration curve was found in good linear range of 0.33–80 μg/mL (r=0.9994). Uptake determination of apigenin in Caco-2 cells depended a certain of time, concentration and pH values, and P-gp inhibitors could not increase the apigenin uptake.Conclusion This method is simple and sensitive. P-gp is not involved in apigenin transport process, and uptake of apigenin in Caco-2 cells is mainly passive transported.
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OBJECTIVE: To develop an analytical method for the quantification of scopoletin (Sco) and investigate the cellular uptake and metabolism of polyvinylcaprolactam-polyvinyl acetate-polyethylene glycol (soluplus)-based Sco micelles (Sco-Ms) in Caco-2 cells, as well as exploring the possible mechanisms involved in the oral absorption of Sco-Ms.METHODS: Combined with enzymatic hydrolysis for pretreatment, a liquid chromatography-electrospray ionization-tandem mass spectrometric (LC-MS/MS) method was developed for the quantification of Sco and its corresponding metabolite. Then, cellular uptake efficiency and metabolic rate of Sco were calculated.RESULTS: This method was proven to be linear over the concentration range of 5-1 000 ng•mL-1. Cellular uptake of Sco-Ms increased significantly compared with that of free Sco at various time points. Meanwhile, Sco-Ms inhibited the enzymatic degradation of Sco. Sco-Ms were primarily internalized into enterocytes via macropinocytosis and clathrin-dependent pathways.CONCLUSION: Enhanced cellular uptake and decreased metabolic rate are pivotal mechanisms by which Sco-Ms promotes oral absorption of Sco.
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ABSTRACT The present study describes the impact of chrysosplenetin, in the absence and presence of artemisinin, on in vitro breast cancer resistance protein-mediated transport activity in Caco-2 cell monolayers using aristolochic acid I as a specific probe substrate. We observed that novobiocin, a known breast cancer resistance protein active inhibitor, increased Papp (AP-BL) of aristolochic acid I 3.13 fold (p < 0.05) but had no effect on Papp (BL-AP). Efflux ratio (PBA/PAB) declined 4.44 fold (p < 0.05). Novobiocin, consequently, showed a direct facilitation on the uptake of AAI instead of its excretion. Oppositely, both artemisinin and chrysosplenetin alone at dose of 10 µM significantly decreased Papp (BL-AP) instead of Papp (AP-BL). Chrysosplenetin alone attenuated the efflux ratio, which was suggestive of being as a potential breast cancer resistance protein suppressant. Oddly, Papp (BL-AP) as well as efflux ratio were respectively enhanced 2.52 and 2.58 fold (p < 0.05), when co-used with artemisinin and chrysosplenetin in ratio of 1:2. The potential reason remains unclear; it might be relative to binding sites competition between artemisinin and chrysosplenetin or the homodimer/oligomer formation of breast cancer resistance protein bridged by disulfide bonds, leading to an altered in vitro breast cancer resistance protein-mediated efflux transport function.
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Objective To explore the role of P-glycoprotein(P-gp)on cellular uptake and metabolism in the transmembrane transport of quercitrin.Methods Caco-2 cell monolayer and P-gp inhibitor Cyclosporin A(CysA)were used in the study.Quercitrin, quercetin,isorhamnetin and tamarixetin were determined by LC-MS to study cellular uptake and metabolism of quercitrin on Caco-2 cells.Results Uptake of quercitrin by Caco-2 cells:in different concentration groups of quercitrin coincubating with and without Cy?sA,intracellular accumulation presented the following characteristics:the amount of quercitrin first rose,reached the peak in 60 min and then declined to a steady-state in 120 min.And meanwhile there were significant differences between the two different processing groups incubating with and without CysA(P<0.05);quercetin was detected in all groups(3.0,9.0 and 27.0 mg/L).But in the higher concentration groups incubating with and without CysA,the intracellular quercetin presented a characteristics similar to its original glycosides and showed a significant difference(P<0.05),while the other groups showed no concentration-and time-dependence.At the same time,isorhamnetin and tamarixetin were detected in two higher concentration groups incubating with and without CysA, which showed the trend similar to the original glycosides but no significant difference was obtained between the two processing groups(P>0.05).Isorhamnetin and tamarixetin were not detected in the low and middle concentration groups.Transmembrane transport:on the basal lateral of all groups,the content of the quercitrin in 150 min incubation time showed a trend of continuous rise,and there was no significant difference between the two processing groups.Quercetin,isorhamnetin and tamarixetin were not detected.Conclu?sion Intact quercitrin could be absorbed into the Caco-2 cells and transported across the Caco-2 cell monolayer,and suffered a series of further metabolism in the Caco-2 cells and the basal side of Caco-2 cell monolayer,leading to different characteristics between intra?cellular accumulation and transmembrane transport.P-gp reduces the transmembrane transport of quercitrin by its efflux function,but did not involved in quercitrin metabolism.
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Aim To investigate the protective effect of paeoniflorin on TNF-α induced intestinal epithelial barrier dysfunction and its mechanisms.Methods The Caco-2 cells were cultured and the MTF assay was used to determine the effects of the paeoniflorin on Caco-2 cell activity.The Caco-2 cell intestinal epithelial barrier dysfunciton model was established through incubation of cells with TNF-α.The effects of paeoniflorin on intestinal epithelial barrier dysfunciton were studied.Results The transmembrane resistance in Caco-2 epithelial barrier was significantly reduced by TNF-α incubation;MLCK significantly increased,while tight junction protein occludin and ZO-1 significantly decreased by TNF-α.These changes were significantly reversed by paeoniflorin,which reduced MLCK expression and enhanced expression of occludin and ZO-1.The protective effects against epithelial barrier dysfunction could be abrogated by small interfering RNA(siRNA) of MLCK.Conclusions Paeoniflorin alleviates the epithelial barrier dysfunction induced by TNF-αthrough down-regulation of MLCK and enhancement of tight junction protein occludin and ZO-1.This study supplies a potential candidate drug for the clinical treatment of inflammatory bowel diseases.
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Objective To explore the effects of arsenic trioxide and paclitaxel on the expression level of metastasis-associated gene 1(MTA1) mRNA in Caco-2 cells.Methods Methylthiazolyldiphenyl-tetrazolium bromide(MTT) assay was performed to detect the inhibition rate of different concentrations of arsenic trioxide and paclitaxel on the growth of Caco-2 cells,reverse transcription real-time polymerase chain reaction was performed to detect the expression level of MTA1 mRNA.Results With the increasing of the concentrations of arsenic trioxide and paclitaxel,the inhibition rate increased,while the expression level of MTA1 mRNA decreased.The inhibition rate was negatively correlated with the expression levle of MTA1 mRNA(r=-0.636,P<0.05).Conclusion The effects of arsenic trioxide and paclitaxel on the growth of Caco-2 cells and the expression level of MTA1 mRNA could be with dosage-dependence,and the inhibition effects might be negatively correlated with the expression level of MTA1 mRNA.
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PAMAM dendrimer is one of the most widely studied dendrimers in recent years, which has a large number of functional groups on the surface and cavities inside, specific three-dimensional structure and good biocompatibility, permeability and stability. It has been widely applied in drug and gene carrier fields and may become a new absorption enhancer. In order to study the absorption enhancing effects of PAMAM dendrimers, liquiritin was selected as the model drug, with the protection of spleen and liver, detoxification and other functions, but it had not been widely used in clinical application because of its difficult absorption, first pass effect, and low bioavailability. This topic was based on the two main determinants (solubility and permeability) of intestinal absorption in the body, researched the physicochemical properties of liquiritin, analyzed the transport volume of liquiritin with or without PAMAM dendrimers by using Caco-2 cell model, and analyzed the cytotoxicity of PAMAM dendrimers on Caco-2 cells by MTT experiments. These results showed that 0.1% of the G4 generation PAG can promote the absorption of liquiritin safely and effectively, and it was suitable for further development into a new type of pharmaceutical excipients.
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ABSTRACT The aim of this study was to provide scientific knowledge to support the use of Vernonia condensata Baker, Asteraceae, beverages for their alleged hypocholesterolemic properties by testing their action as HMG-CoA reductase inhibitors and their capacity to lower dietary cholesterol permeation. Chlorogenic acid, and other caffeoylquinic acids derivatives were identified as the main components of these beverages by LC–MS/MS. No changes in the composition were notice after the in vitro gastrointestinal digestion and no toxicity against Caco-2 and HepG2 cell lines was detected. Cholesterol permeation through Caco-2 monolayers was reduced in 37% in the presence of these herbal teas, and the caffeoylquinic acids permeated the monolayers in 30–40% of their initial amount in 6 h. HMG-CoA reductase activity was reduced with these beverages, showing an IC50 of 217 µg ml−1. It was concluded that caffeoylquinic acids, the major components, justified 98% of the enzyme inhibition measured.
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Objective To investigate the role of Rho kinase (ROCK) in the protective effects of hydrogen on intestinal epithelial barrier function in sepsis. Methods Caco-2 cells were cultured routinely, and divided into 6 groups randomly (n=3):control group (C group), hydrogen-rich medium group (H group), lipopolysaccharide (LPS)-treatment group (L group), hy?drogen+LPS-treatment group (HL group), Rho kinase inhibitor (Y-37632) treatment group (Y group) and Rho kinase inhibi?tor Y-27632+LPS-treatment group (YL group). H group was treated with 0.6 mmol/L hydrogen-rich media. The concentra?tion of LPS and Y-27632 were 50 mg/L and 25μmol/L separately. After the Caco-2 monolayer model was established, the transepithelial electrical resistance (TEER) values were measured regularly. When the TEER value reached 800Ω·cm2, the treatment was administered. Then TEER values were measured at 6 h, 12 h and 24 h, and FITC-dextran permeability was de?tected at 24 h. Cells were seeded on 6-well plates. After cell density reached 80%-90%, treatments were given randomly. The real time-polymerase chain reaction (RT-PCR) was conducted to assess mRNA levels of ZO-1 and ROCK mRNA. ZO-1 and ROCK protein expression levels were detected by Western blot assay. Results Compared with C group, TEER values were elevated in 12 h and 24 h in H group (P protein expression levels of ZO-1 and ROCK between C group and H group (P>0.05). TEER values were elevated at 6 h, 12 h and 24 h in Y group (P 0.05). The mRNA expression of ZO-1 increased and mRNA expression of ROCK decreased in Y group (P <0.05). The TEER values reduced at 6 h, 12 h and 24 h in L group. The FITC-dextran permeability increased significantly, mRNA and protein expressions of ZO-1 significantly decreased, mRNA and protein expressions of ROCK significantly in?creased in L group (all P<0.05). Compared with L group, TEER values increased significantly at 6 h, 12 h and 24 h in YL group, FITC-dextran permeability decreased, mRNA expressions of ZO-1 increased, mRNA expressions of ROCK de?creased in YL group (P<0.05). Compared with L group, TEER values increased at 6 h, 12 h and 24 h in HL group, FITC-dextran permeability reduced markedly, protein expressions of ZO-1 increased at each time point, protein expressions of ROCK decreased at each time point in HL group (P<0.05). Conclusion Hydrogen can protect intestinal barrier function against sepsis, ameliorate the integrity and permeability of intestinal epithelium and increase the expressions of intercellular tight junction proteins. The suppression of Rho kinase over-expression induced by LPS may be involved in these protective effects of hydrogen.
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Objective: To develop 5-FU multiple emulsion entrapped into thermo-sensitive gel (5-FU-DEG) and detect the ab-sorption and transportation in Caco-2 cell monolayer model. Methods:The 5-FU multiple emulsion was prepared by a two-step emulsif-ying method. Poloxamer 407 (P407) was used as the thermo-sensitive material and sodium alginate (SA) was used as the bioadhesive material for the preparation of 5-FU-DEG. Caco-2 cell monolayer model was used to investigate the transportation and absorption of 5-FU. Results:5-FU-DEG gelled at the ambient temperature and turned into liquid below 10℃ The apparent permeability coefficient (Papp) of 5-FU-DEG was 1.47 ±0.11 ×10 -5(cm·s-1), which was about 6 times higher than that of 5-FU water solution(2.39 ± 0.21 ×10 -6 cm·s-1)(P<0.01). The cellular uptake rate of 5-FU-DEG was (17.1 ±0.24) %, which was 3.9 times greater than that of 5-FU water solution (4. 41 ± 0. 23%)(P<0. 01). Conclusion:5-FU-DEG can efficiently enhance the transportation and ab-sorption of drug in rectal site by using micro-emulsion technology combined with thermo-sensitive technology, which can be an effective rectal delivery system for 5-FU to treat rectal cancer.
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OBJECTIVE:To investigate the function change of intestinal CYP3A4 and P-glycoprotein (P-gp) under diabetic conditions and its mechanism. METHODS:Caco-2 cells were respectively added with 25, 50 and 100 μmol/L midazolam (CYP3A4 probe substrate) for incubation for 15,30,60,120,180 min;with 0.1,0.2,0.4 μg/ml rhodamine 123 (P-gp sub-strate)for incubation for 15,30,60,90,120 min to determine the substrate concentrations and incubation time. Caco-2 cells were added with insulin,glucose and fatty acid (palmitic acid and oleic acid) at different concentrations,and then the production of 1′-OH-midazolam,the metabolite of midazolam,and the intake of rhodamine 123 were determined,in order to investigated the ef-fect on the function of CYP3A4 and P-gp. RESULTS:The optimal substrate concentrations and incubation time were as follows as 50 μmol/L midazolam,0.1 μg/ml rhodamine 123 and incubation for 2 h. With the increase in the concentration of insulin,glucose and palmitic acid,the production of 1′-OH-midazolam and the activity of CYP3A4 reduced;the intake of rhodamine 123 in-creased,and the efflux transport function of P-gp decreased. Oleic acid had no significant effect on the production of 1′-OH-mid-azolam or the intake of rhodamine 123. CONCLUSIONS:Under diabetes condition,the increase of insulin,glucose and palmitic acid may reduce the function of CYP3A4 and P-gp,while oleic acid has no effect on the function.