Precision cut intestinal slices are an appropriate ex vivo model to study NSAID-induced intestinal toxicity in rats

In vitro toxicity of two functionalized reduced graphene oxide materials with potential application in food packaging

Functionalized graphene materials have been proposed as nanofillers in food packaging applications as they improve the characteristics of the resulting nanocomposites. But food contact materials require a toxicity evaluation previous their authorization and use. In this sense, reduced graphene oxide functionalized with dodecyl amine (DA-rGO), and [2-(methacryloyloxy) ethyl] trimethylammonium chloride (MTAC-rGO) were characterized and their internalization and cytotoxicity in Caco-2 and HepG2 cultures evaluated. Cell viability decreased from 100 μg/mL in all experimental trials, and oxidative stress by means of a reduction in glutathione levels was evidenced as one of the potential toxicity mechanisms involved. Moreover, both materials were subjected to an in vitro digestion process to investigate their potential changes along the gastrointestinal tract. Digested samples were characterized, and the cytotoxicity also evaluated showing an exacerbation. These results raise concerns about the impact of these materials after oral exposure, and therefore further research is necessary.

Toxic effects of environmentally relevant concentrations of naproxen exposure on Daphnia magna including antioxidant system, development, and reproduction

Naproxen (NPX) is one of common non-prescription non-steroidal anti-inflammatory drugs (NSAIDs) which is widely detected in aquatic environments worldwide due to its high usage and low degradation. NPX exerts anti-inflammatory and analgesic pharmacological effects through the inhibition of prostaglandin-endoperoxide synthase (PTGS), also known as cyclooxygenase (COX). Given its evolutionarily relatively conserved biological functions, the potential toxic effects of NPX on non-target aquatic organisms deserve more attention. However, the ecotoxicological studies of NPX mainly focused on its acute toxic effects under higher concentrations while the chronic toxic effects under realistic concentrations exposure, especially for the underlying molecular mechanisms still remain unclear. In the present study, Daphnia magna, being widely distributed in freshwater aquatic environments, was selected to investigate the toxic effects of environmentally relevant concentrations of NPX via determining the response of the Nrf2/Keap1 signaling pathway-mediated antioxidant system in acute exposure, as well as the changes in life-history traits, such as growth, reproduction, and behavior in chronic exposure. The results showed that the short-term exposure to NPX (24 h and 48 h) suppressed ptgs2 expression while activating Nrf2/Keap1 signaling pathway and its downstream antioxidant genes (ho-1, sod, cat and trxr). However, with prolonged exposure to 96 h, the opposite performance was observed, the accumulation of malondialdehyde (MDA) indicated that D. magna suffered from severe oxidative stress. To maintain homeostasis, the exposed organism may trigger ferroptosis and apoptosis processes with the help of Silent mating type information regulation 2 homologs (SIRTs). The long-term chronic exposure to NPX (21 days) caused toxic effects on D. magna at the individual and population levels, including growth, reproduction and behavior, which may be closely related to the oxidative stress induced by the drug. The present study suggested that more attention should be paid to the ecological risk assessment of NSAIDs including NPX on aquatic non-target organisms.

Impact of Gastrointestinal Digestion In Vitro Procedure on the Characterization and Cytotoxicity of Reduced Graphene Oxide

The growing interest in graphene derivatives is a result of their variety of applications in many fields. Due to their use, the oral route could be a potential way of entrance for the general population. This work assesses the biotransformation of reduced graphene oxide (rGO) after an in vitro digestion procedure (mouth, gastric, intestinal, and colon digestion), and its toxic effects in different cell models (HepG2, Caco-2, and 3D intestinal model). The characterization of rGO digestas evidenced the agglomeration of samples during the in vitro gastrointestinal (g.i.) digestion. Internalization of rGO was only evident in Caco-2 cells exposed to the colonic phase and no cellular defects were observed. Digestas of rGO did not produce remarkable cytotoxicity in any of the experimental models employed at the tested concentrations (up to 200 µg/mL), neither an inflammatory response. Undigested rGO has shown cytotoxic effects in Caco-2 cells, therefore these results suggest that the digestion process could prevent the systemic toxic effects of rGO. However, additional studies are necessary to clarify the interaction of rGO with the g.i. tract and its biocompatibility profile.

NSAID-Associated Small Intestinal Injury: An Overview From Animal Model Development to Pathogenesis, Treatment, and Prevention

With the wide application of non-steroidal anti-inflammatory drugs (NSAIDs), their gastrointestinal side effects are an urgent health burden. There are currently sound preventive measures for upper gastrointestinal injury, however, there is a lack of effective defense against lower gastrointestinal damage. According to a large number of previous animal experiments, a variety of NSAIDs have been demonstrated to induce small intestinal mucosal injury in vivo. This article reviews the descriptive data on the administration dose, administration method, mucosal injury site, and morphological characteristics of inflammatory sites of various NSAIDs. The cells, cytokines, receptors and ligands, pathways, enzyme inhibition, bacteria, enterohepatic circulation, oxidative stress, and other potential pathogenic factors involved in NSAID-associated enteropathy are also reviewed. We point out the limitations of drug modeling at this stage and are also pleased to discover the application prospects of chemically modified NSAIDs, dietary therapy, and many natural products against intestinal mucosal injury.

Gutsy science: In vitro systems of the human intestine to model oral drug disposition

The intestine has important gate-keeping functions that can profoundly affect the systemic blood exposure of orally administered drugs. Thus, characterizing a new molecular entity's (NME) disposition within the intestine is of utmost importance in drug development. While currently used in vitro systems, such as Ussing chamber, precision-cut intestinal slices, immortalized cell lines, and primary enterocytes provide substantial knowledge about drug absorption and the intestinal first-pass effect, they remain sub-optimal for quantitatively predicting this process and the oral bioavailability of many drugs. Use of novel in vitro systems such as intestinal organoids and intestinal microphysiological systems have provided substantial advances over the past decade, expanding our understanding of intestinal physiology, pathology, and development. However, application of these emerging in vitro systems in the pharmaceutical science is in its infancy. Preliminary work has demonstrated that these systems more accurately recapitulate the physiology and biochemistry of the intact intestine, as it relates to oral drug disposition, and thus they hold considerable promise as preclinical testing platforms of the future. Here we review currently used and emerging in vitro models of the human intestine employed in pharmaceutical science research. We also highlight aspects of these emerging tools that require further study.

High concentrations of ammonia induced cytotoxicity and bronchoconstriction in a precision-cut lung slices rat model

Exposure to high concentrations of ammonia (NH3) can cause life-threatening lung damages. The objective of this study was to establish a translational in vitro model for NH3-induced lung injury. Precision-cut lung slices (PCLS) from rats were exposed to NH3 and toxicological responses and cell viability were quantified by analysis of LDH, WST-1, inflammatory mediators (IL-1β, IL-6, CINC-1, MMP-9, RAGE and IL-18), and by microscopic evaluation of bronchoconstriction induced by electric-field-stimulation (EFS) or methacholine (MCh). Different treatment strategies were assessed to prevent or reverse the damages caused by NH3 using anti-inflammatory, anti-oxidant or neurologically active drugs. Exposure to NH3 caused a concentration-dependent increase in cytotoxicity (LDH/WST-1) and IL-1β release in PCLS medium. None of the treatments reduced cytotoxicity. Deposition of NH3 (24-59 mM) on untreated PCLS elicited an immediate concentration-dependent bronchoconstriction. Unlike MCh, the EFS method did not constrict the airways in PCLS at 5 h after NH3-exposure (47-59 mM). Atropine and TRP-channel antagonists blocked EFS-induced bronchoconstriction but these inhibitors could not block the immediate NH3-induced bronchoconstriction. In conclusion, NH3 exposure caused cytotoxic effects and lung damages in a concentration-dependent manner and this PCLS method offers a way to identify and test new concepts of medical treatments and biomarkers that may be of prognostic value.

Bi-aryl Analogues of Salicylic Acids: Design, Synthesis and SAR Study to Ameliorate Endoplasmic Reticulum Stress

Introduction

Endoplasmic reticulum (ER) stress condition is characterized as the accumulation of misfolded or unfolded proteins in lumen of ER. This condition has been implicated in various diseases and pathologies including β-cell apoptosis, Alzheimer’s disease and atherosclerosis. We have reported that hydroxynaphthoic acids (HNA), naphthalene analogues of salicylic acid (SA), reduced ER stress. In this study, we explored structural modification to bi-aryl analogues of SA.

Methods

Palladium-catalyzed cross-coupling was applied to synthesize bi-aryl analogues of SA. Anti-ER stress activity was monitored by using our cell-based assay system where ER stress is induced by tunicamycin. To monitor ER stress markers, ER stress was induced physiologically relevant palmitate system.

Results

Many analogues decreased ER stress signal induced by tunicamycin. Compounds creating dihedral angle between Ar group and SA moiety generally increased the activity but gave some cytotoxicity to indicate the crucial role of flat conformation of aromatic region. The best compound (16e) showed up to almost 6-fold and 90-fold better activity than 3-HNA and tauro-ursodeoxycholic acid, positive controls, respectively. ER stress markers such as p-PERK and p-JNK were accordingly decreased in Western blotting upon treatment of 16e under palmitate-induced condition.

Conclusion

Anti-ER stress activity and toxicity profile of bi-aryl analogues of SA could provide a novel platform for potential therapy for protein misfolding diseases.

Modulation of non-steroidal anti-inflammatory drug-induced, ER stress-mediated apoptosis in Caco-2 cells by different polyphenolic antioxidants: a mechanistic study

OBJECTIVES

Direct scavenging of reactive oxygen species could not prevent ER stress-associated cytotoxicity of indomethacin or diclofenac in Caco-2 cells. This study investigated the effects of three polyphenolic antioxidants epigallocatechin gallate (EGCG), phyllanthin and hypophyllathin in non-steroidal anti-inflammatory drug-induced Caco-2 apoptosis.

METHODS

Cells were treated with ER stressors (indomethacin, diclofenac, tunicamycin or thapsigargin) and the polyphenols for up to 72 h. Cell viability, apoptosis and mitochondrial function were monitored by MTT, Hoechst 33342 and TMRE assays, respectively. Protein expression was measured by Western blot analysis.

KEY FINDINGS

Epigallocatechin gallate suppressed increases in p-PERK/p-eIF-2α/ATF-4/CHOP and p-IRE-1α/p-JNK1/2 expression levels in the cells treated with any of the ER stressors, leading to inhibition of apoptosis. In contrast, phyllanthin increased apoptosis in the cells subsequently exposed to either diclofenac, tunicamycin or thapsigargin, but not in the indomethacin-treated cells. The potentiation effect of phyllanthin seen with the three ER stressors was related to suppression of survival p-Nrf-2/HO-1 expression, resulting in increased activation of the eIF-2α/ATF-4/CHOP pathway. On the other hand, hypophyllanthin had no significant effect on the ER stressor-induced apoptosis.

CONCLUSION

Epigallocatechin gallate, phyllanthin and hypophyllanthin displayed different effects in the ER stress-mediated apoptosis, depending upon their interaction with the specific unfolded protein response signalling.

The Past, Present and Future of Intestinal In Vitro Cell Systems for Drug Absorption Studies

The intestinal epithelium acts as a selective barrier for the absorption of water, nutrients and orally administered drugs. To evaluate the gastrointestinal permeability of a candidate molecule, scientists and drug developers have a multitude of cell culture models at their disposal. Static transwell cultures constitute the most extensively characterized intestinal in vitro system and can accurately categorize molecules into low, intermediate and high permeability compounds. However, they lack key aspects of intestinal physiology, including the cellular complexity of the intestinal epithelium, flow, mechanical strain, or interactions with intestinal mucus and microbes. To emulate these features, a variety of different culture paradigms, including microfluidic chips, organoids and intestinal slice cultures have been developed. Here, we provide an updated overview of intestinal in vitro cell culture systems and critically review their suitability for drug absorption studies. The available data show that these advanced culture models offer impressive possibilities for emulating intestinal complexity. However, there is a paucity of systematic absorption studies and benchmarking data and it remains unclear whether the increase in model complexity and costs translates into improved drug permeability predictions. In the absence of such data, conventional static transwell cultures remain the current gold-standard paradigm for drug absorption studies.

Time-Resolved Quantification of Nanoparticle Uptake, Distribution, and Impact in Precision-Cut Liver Slices

Much effort within the nanosafety field is currently focused on the use of advanced in vitro models to reduce the gap between in vitro and in vivo studies. Within this context, precision-cut tissue slices are a unique ex vivo model to investigate nanoparticle impact using live tissue from laboratory animals and even humans. However, several aspects of the basic mechanisms of nanoparticle interactions with tissue have not yet been elucidated. To this end, liver slices are exposed to carboxylated and amino-modified polystyrene known to have a different impact on cells. As observed in standard cell cultures, amino-modified polystyrene nanoparticles induce apoptosis, and their impact is affected by the corona forming on their surface in biological fluids. Subsequently, a detailed time-resolved study of nanoparticle uptake and distribution in the tissue is performed, combining fluorescence imaging and flow cytometry on cells recovered after tissue digestion. As observed in vivo, the Kupffer cells accumulate high nanoparticle amounts and, interestingly, they move within the tissue towards the slice borders. Similar observations are reproduced in liver slices from human tissue. Thus, tissue slices can be used to reproduce ex vivo important features of nanoparticle outcomes in the liver and study nanoparticle impact on real tissue.

Natural polyphenols prevent indomethacin-induced and diclofenac-induced Caco-2 cell death by reducing endoplasmic reticulum stress regardless of their direct reactive oxygen species scavenging capacity

Objectives

Indomethacin (INDO) and diclofenac (DIC) can induce intestinal cell death through induction of oxidative stress-mediated ER stress and mitochondrial dysfunction. This study investigated the cytoprotective potential of 11 polyphenols, namely caffeic acid (CAF), curcumin (CUR), epigallocatechin gallate (EGCG), gallic acid (GAL), hypophyllanthin (HYPO), naringenin (NAR), phyllanthin (PHY), piperine (PIP), quercetin (QUE), rutin (RUT) and silymarin (SLY) against these two NSAIDs in Caco-2 cells.

Methods

Reactive oxygen species (ROS) production was determined with fluorescence spectroscopy using specific probes (DHE, DCFH-DA, HPF). Cell viability and mitochondrial function were assessed by MTT and TMRE assays. The mRNA levels of Bax, Bcl-2 and CHOP proteins were determined by quantitative real-time polymerase chain reaction technique.

Key findings

All test polyphenols reduced NSAIDs-mediated ROS production. Only EGCG, QUE and RUT protected INDO-/DIC-induced cell death. These three polyphenols suppressed Bax/Bcl-2 mRNA ratio, CHOP up-regulation and MMP disruption in NSAIDs-treated cells. CAF and NAR prevented cytotoxicity from INDO, but not DIC. The cytoprotective effect of NAR, but not CAF, involved alteration of Bax/Bcl-2 mRNA ratio or MMP disruption, but not CHOP transcription.

Conclusion

The cytoprotective activity of polyphenols against NSAIDs-induced toxicity stemmed from either suppression of CHOP-related ER and mitochondria stresses or other CHOP-independent pathways, but not from the intrinsic ROS scavenging capacity.

Berberine ameliorates non-steroidal anti-inflammatory drugs-induced intestinal injury by the repair of enteric nervous system

The study was to detect the role of GDNF, PGP9.5 (a neuronal marker), and GFAP (EGCs' marker) in the mechanism of non-steroidal anti-inflammatory drugs (NSAIDs) related to intestinal injury and to clarify the protective effect of berberine in the treatment of NSAID-induced small intestinal disease. Forty male SD rats were divided randomly into five groups (A-E): Group A: control group; Group B: model group received diclofenac sodium 7.5 mg/(kg*day) for 5 days; Group C-E: berberine low, medium and high dose groups were treated by 7.5 mg/(kg*day) diclofenac sodium for 5 days then received berberine 25 mg/(kg*day), 50 mg/(kg*day), and 75 mg/(kg*day), respectively, between the sixth and eighth day. Intestinal mucosa was taken on the ninth day to observe the general, histological injuries, and to measure the intestinal epithelial thickness. Then, immunohistochemistry was performed to detect the expression of PGP9.5 and GFAP, and Western blot was performed to detect GDNF expression. The histological score and the general score in the model group were, respectively, 5.75 ± 1.04 and 4.83 ± 0.92. Scores in berberine medium and high berberine group were lower compared with the model group (P < 0.05). The intestinal epithelial thickness in the model group was lower than in the control group and the berberine groups (P < 0.05). PGP9.5, GFAP, and GDNF content in the model group and the three berberine groups were significantly lower than in the control groups (P < 0.05). PGP9.5, GFAP, and GDNF content in the control group and the three berberine groups were higher compared with the model groups (P < 0.05). Berberine can protect the intestinal mucosa of NSAID users, and the mechanism is associated with the reparation of the enteric nervous system via upregulating the expression of PGP9.5, GFAP, and GDNF.

In vitro estimation of metal-induced disturbance in chicken gut-oviduct chemokine circuit

Backgrounds

Heavy metals affect various processes in the embryonic development. Embryonic fibroblasts (EFs) play key roles in the innate recognition and wound healing in reproductive tissues.

Methods

Based on the relative toxicities of different inorganic metals and inorganic nonmetallic compounds against murine and chicken EF cells, mechanistic estimations were performed based on transcriptomic analyses.

Results

Lead (II) acetate induced preferential injuries in the chicken EF and mechanistic analyses using transcriptome revealed that chemokine receptor-associated events are potently involved in metal-induced adverse actions. As an early sentinel of metal exposure, the precision-cut intestine slices (PCIS) induced the expression of chemokines including CXCLi1 or CXCLi2, which were potent gut-derived factors that activate chemokine receptors in reproductive organs after circulation.

Conclusion

EF-selective metals can be estimated to trigger the chemokine circuit in the gut-reproductive axis of chickens. This in vitro methodology using PCIS-EF culture could be used as a promising alternate platform for the reproductive immunotoxicological assessment.

Understanding the effect of repeated administration of meloxicam on feline renal cortex and medulla: A lipidomics and metabolomics approach

Repeated administration of meloxicam can cause kidney damage in cats by mechanisms that remain unclear. Metabolomics and lipidomics are powerful, noninvasive approaches used to investigate tissue response to drug exposure. Thus, the objective of this study was to assess the effects of meloxicam on the feline kidney using untargeted metabolomics and lipidomics approaches. Female young-adult purpose-breed cats were allocated into the control (n = 4) and meloxicam (n = 4) groups. Cats in the control and meloxicam groups were treated daily with saline and meloxicam at 0.3 mg/kg subcutaneously for 17 days, respectively. Renal cortices and medullas were collected at the end of the treatment period. Random forest and metabolic pathway analyses were used to identify metabolites that discriminate meloxicam-treated from saline-treated cats and to identify disturbed metabolic pathways in renal tissue. Our results revealed that the repeated administration of meloxicam to cats altered the kidney metabolome and lipidome and suggest that at least 40 metabolic pathways were altered in the renal cortex and medulla. These metabolic pathways included lipid, amino acid, carbohydrate, nucleotide and energy metabolisms, and metabolism of cofactors and vitamins. This is the first study using a pharmacometabonomics approach for studying the molecular effects of meloxicam on feline kidneys.

Development of a Novel Ex-vivo 3D Model to Screen Amoebicidal Activity on Infected Tissue

Amoebiasis is a parasitic disease that causes thousands of deaths every year, its adverse effects and resistance to conventional treatments have led to the search of new treatment options, as well as the development of novel screening methods. In this work, we implemented a 3D model of intestine and liver slices from hamsters that were infected ex vivo with virulent E. histolytica trophozoites. Results show preserved histology in both uninfected tissues as well as ulcerations, destruction of the epithelial cells, and inflammatory reaction in intestine slices and formation of micro abscesses, and the presence of amoebae in the sinusoidal spaces and in the interior of central veins in liver slices. The three chemically synthetized compounds T-001, T-011, and T-016, which act as amoebicides in vitro, were active in both infected tissues, as they decreased the number of trophozoites, and provoked death by disintegration of the amoeba, similar to metronidazole. However, compound T-011 induced signs of cytotoxicity to liver slices. Our results suggest that ex vivo cultures of precision-cut intestinal and liver slices represent a reliable 3D approach to evaluate novel amoebicidal compounds, and to simultaneously detect their toxicity, while reducing the number of experimental animals commonly required by other model systems.

Repeated administration of the NSAID meloxicam alters the plasma and urine lipidome

Non-steroidal anti-inflammatories (NSAIDs), such as meloxicam, are the mainstay for treating painful and inflammatory conditions in animals and humans; however, the repeated administration of NSAIDs can cause adverse effects, limiting the long-term administration of these drugs to some patients. The primary aim of this study was to determine the effects of repeated meloxicam administration on the feline plasma and urine lipidome. Cats (n = 12) were treated subcutaneously with either saline solution or 0.3 mg/kg body weight of meloxicam daily for up to 31 days. Plasma and urine lipidome were determined by LC-MS before the first treatment and at 4, 9 and 13 and 17 days after the first administration of meloxicam. The repeated administration of meloxicam altered the feline plasma and urine lipidome as demonstrated by multivariate statistical analysis. The intensities of 94 out of 195 plasma lipids were altered by the repeated administration of meloxicam to cats (p < 0.05). Furthermore, we identified 12 lipids in plasma and 10 lipids in urine that could serve as biomarker candidates for discriminating animals receiving NSAIDs from healthy controls. Expanding our understanding about the effects of NSAIDs in the body could lead to the discovery of mechanism(s) associated with intolerance to NSAIDs.

The use of liver slices from the Cape vulture (Gyps coprotheres) to better understand the role of liver toxicity of non-steroidal anti-inflammatory drugs (NSAIDs) in vultures

Diclofenac, a non-steroidal anti-inflammatory drug (NSAID) was responsible for the death of millions of vultures on the Asian subcontinent, following the consumption of diclofenac contaminated carcasses. The aim of this research was to establish if liver slices could serve as an alternate means of predicting the toxicity of NSAIDs in Gyps vultures. The Cape vulture liver slices was prepared and incubated with four NSAIDs for 6 h. A percent clearance of 1.0 ± 0.253, 0.58 ± 0.153, 0.961 ± 0.312 and 1.242 ± 0.406 (%/h*g) was attained for diclofenac, carprofen, ketoprofen and meloxicam respectively. Both meloxicam and diclofenac exerted toxic effects on the hepatic cells. Protein content indicated that the vulture tissue had lower enzyme levels than expected for an animal of its size. The poor distinction between the ex vivo hepatic percent clearance of meloxicam and diclofenac indicates that liver slices is not an ideal model to investigate NSAIDs toxicity in Cape vulture.

Infection of porcine precision cut intestinal slices by transmissible gastroenteritis coronavirus demonstrates the importance of the spike protein for enterotropism of different virus strains

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Porcine precision cut intestinal slices can be used to analyze virus infection.

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TGEV strains differ in their ability to infect cells of the jejunal epithelium.

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Enterotropism of TGEV is determined by its spike protein S.

TGEV is a coronavirus that is still widely spread in pig farming. On molecular level this virus has been studied in detail. However, studying TGEV infection within the complexity of the porcine intestinal epithelium reveals difficulties due to limiting infection models. Here we established a new ex vivo model to analyze the enterotropism of TGEV in porcine intestinal tissue. Precision cut intestinal slices (PCIS) were produced and ATP level was measured to proof vitality of the slices. ATP measurements and HE staining revealed living tissue in culture for up to 24 h. PCIS were infected with three different TGEV strains. TGEV PUR 46-MAD is a commonly used TGEV strain that is known to be attenuated. TGEV Miller was passaged in piglets several times to reveal high infection. Finally, TGEV GFP is a recombinant strain that obtained its main body from TGEV PUR 46-MAD, but its spike protein from TGEV PUR-C11 that showed high mortality in piglets in vivo. Our results were in complete consensus of these statements. TGEV Miller mildly and TGEV GFP extensively infected the cells in the jejunum based on the amount of positive stained epithelial cells. However, for TGEV PUR 46-MAD no nucleocapsid protein was detected in the epithelial cells of the tissue. This shows that differences in TGEV strains and their infectious potential are highly dependent on their S protein.

In Vitro Intestinal and Liver Models for Toxicity Testing

The human body is exposed to hundreds of chemicals every day. Many of these toxicants have unknown effects on the body that can be deleterious. Furthermore, chemicals can have a synergistic effect, resulting in toxic responses of cocktails at relatively low individual exposure levels. The gastrointestinal (GI) tract and the liver are the first organs to be exposed to ingested pharmaceuticals and environmental chemicals. As a result, these organs often experience extensive damage from xenobiotics and their metabolites. In vitro models offer a promising method for testing toxic effects. Many advanced in vitro models have been developed for GI and liver toxicity. These models strive to recapitulate the in vivo organ architecture to more accurately model chemical toxicity. In this review, we discuss many of these advances, in addition to recent efforts to integrate the GI and the liver in vitro for a more holistic toxicity model.

Role of endoplasmic reticulum stress in drug-induced toxicity

Drug‐induced toxicity is a key issue for public health because some side effects can be severe and life‐threatening. These adverse effects can also be a major concern for the pharmaceutical companies since significant toxicity can lead to the interruption of clinical trials, or the withdrawal of the incriminated drugs from the market. Recent studies suggested that endoplasmic reticulum (ER) stress could be an important event involved in drug liability, in addition to other key mechanisms such as mitochondrial dysfunction and oxidative stress. Indeed, drug‐induced ER stress could lead to several deleterious effects within cells and tissues including accumulation of lipids, cell death, cytolysis, and inflammation. After recalling important information regarding drug‐induced adverse reactions and ER stress in diverse pathophysiological situations, this review summarizes the main data pertaining to drug‐induced ER stress and its potential involvement in different adverse effects. Drugs presented in this review are for instance acetaminophen (APAP), arsenic trioxide and other anticancer drugs, diclofenac, and different antiretroviral compounds. We also included data on tunicamycin (an antibiotic not used in human medicine because of its toxicity) and thapsigargin (a toxic compound of the Mediterranean plant Thapsia garganica) since both molecules are commonly used as prototypical toxins to induce ER stress in cellular and animal models.

Consequences of Mrp2 deficiency for diclofenac toxicity in the rat intestine ex vivo

The non-steroidal anti-inflammatory drug diclofenac (DCF) has a high prevalence of intestinal side effects in humans and rats. It has been reported that Mrp2 transporter deficient rats (Mrp2) are more resistant to DCF induced intestinal toxicity. This was explained in vivo by impaired Mrp2-dependent biliary transport of DCF-acylglucuronide (DAG), leading to decreased intestinal exposure to DAG and DCF. However, it is not known to what extent adaptive changes in the Mrp2 intestine itself influence its sensitivity to DCF toxicity without the influence of liver metabolites. To investigate this, DCF toxicity and disposition were studied ex vivo by precision-cut intestinal slices and Ussing chamber using intestines from wild type(WT) and Mrp2 rats. The results show that adaptive changes due to Mrp2 deficiency concerning Mrp2, Mrp3 and BCRP gene expression, GSH content and DAG formation were different between liver and intestine. Furthermore, Mrp2 intestine was intrinsically more resistant to DCF toxicity than its WT counterpart ex vivo. This can at least partly be explained by a reduced DCF uptake by the Mrp2 intestine, but isnot related to the other adaptive changes in the intestine. The extrapolation of this data to humans with MRP2 deficiency is uncertain due to species differences in activity and regulation of transporters.

Biliary tract external drainage increases the expression levels of heme oxygenase-1 in rat livers

BACKGROUND

Heme oxygenase-1 (HO-1) protects cells by anti-oxidation, maintaining normal microcirculation and anti-inflammatory under stress. This study investigated the effects of biliary tract external drainage (BTED) on the expression levels of HO-1 in rat livers.

METHODS

Biliary tract external drainage was performed by inserting a cannula into the bile duct. Sixty Sprague-Dawley rats were randomized to the following groups: sham 1 h group; BTED 1 h group; bile duct ligation (BDL) 1 h group; sham 6 h group and BTED 6 h group. The expression levels of HO-1 mRNA were analyzed using real-time RT-PCR. The expression levels of HO-1 were analyzed using immunohistochemistry.

RESULTS

The expression levels of HO-1 mRNA in the liver of the BTED group increased significantly compared with the sham group 1 and 6 h after surgery (p < 0.05).The expression levels of HO-1 in the BTED group increased significantly compared with the sham group 1 and 6 h after surgery. The expression levels of HO-1 mRNA in the liver in the BDL group decreased significantly compared with the sham group 1 h after surgery (p < 0.05).The expression levels of HO-1 in the BDL group decreased significantly compared with the sham group at this time.

CONCLUSION

Biliary tract external drainages increase the expression levels of HO-1 in the liver.

Protective effects of Lycium barbarum polysaccharides against carbon tetrachloride-induced hepatotoxicity in precision-cut liver slices in vitro and in vivo in common carp (Cyprinus carpio L.)

The protective effects of Lycium barbarum polysaccharides (LBPs) against carbon tetrachloride-induced hepatotoxicity in common carp were investigated in vitro and in vivo. Precision-cut liver slices (PCLSs) were employed as an in vitro model system. LBPs (0.1, 0.3 and 0.6 mg/ml) was added to PCLSs culture system before (pre-treatment), after (post-treatment) and both before and after (pre- and post-treatment) the exposure of PCLSs to 12 mM CCl4. The supernatants and PCLSs were collected for biochemical analyses. Results showed that LBPs inhibited the elevations of the marker enzymes (GOT, GPT, LDH and AKP) and MDA induced by CCl4 in all LBPs treatments and it also enhanced the suppressed antioxidant enzymes (SOD, CAT, GSH-Px, GST) and GSH, in the pre-treatment and pre- and post-treatment. In vivo, fish were fed diets containing LBPs at 0.1, 0.5 and 1% for 60 d before an intraperitoneal injection of 30% CCl4 in olive oil at a volume of 0.05 ml/10 g body weight. At 72 h post-injection, blood and liver samples were taken for biochemical analyses. Results showed that LBPs at 0.5 and 1% significantly reduced the levels of GOT, GPT and LDH in the serum; the decreases of the antioxidant enzymes and the increase of MDA in the liver tissue were inhibited markedly. Moreover, LBPs even at lower concentration exerted a potent DPPH scavenging activity. Overall results prove the hepatoprotective and antioxidant effects of LBPs and support the use of LBPs as a hepatoprotective agent in fish.