Rat Bladder Epithelium Research Articles

Evaluation of the Mechanisms Involved in the Development of Bladder Toxicity following Exposure to Occupational Bladder Cancer Causative Chemicals Using DNA Adductome Analysis.

Occupational exposure to aromatic amines (AAs) is an important risk factor for urinary bladder cancer. This study aimed to evaluate the toxicity of AAs and analyze the carcinogenic mechanisms in rat bladder by comprehensive analysis of DNA adducts (DNA adductome). DNA was extracted from the bladder epithelia of rats treated with AAs, including acetoacet-o-toluidine (AAOT) and o-toluidine (OTD), and adductome analysis was performed. Principal component analysis-discriminant analysis revealed that OTD and AAOT observed in urinary bladder hyperplasia could be clearly separated from the controls and other AAs. After confirming the intensity of each adduct, four adducts were screened as having characteristics of the OTD/AAOT treatment. Comparing with the in-house DNA adduct database, three of four candidates were identified as oxidative DNA adducts, including 8-OH-dG, based on mass fragmentation together with high-resolution accurate mass (HRAM) spectrometry data. Therefore, findings suggested that oxidative stress may be involved in the toxicity of rat bladder epithelium exposed to AAs. Consequently, the administration of apocynin, an inhibitor of nicotinamide adenine dinucleotide phosphate oxidase, in six-week-old rats fed with 0.6% OTD in their diet resulted in simple hyperplastic lesions in the bladder that were suppressed by apocynin. The labeling indices of Ki67, γ-H2AX, and 8-OHdG were significantly decreased in an apocynin concentration-dependent manner. These findings indicate that oxidative stress may have contributed to the development of urinary cancer induced by OTD.

LncRNA MEG3 alleviates interstitial cystitis in rats by upregulating Nrf2 and inhibiting the p38/NF-κB pathway

PurposeInterstitial cystitis (IC), a chronic pain syndrome characterized by urinary frequency, urgency, and bladder or pelvic floor pain, severely affects the quality of life of patients. The aim of this study was to investigate the role and mechanism of long noncoding RNA Maternally Expressed Gene3 (lncRNA MEG3) in IC. MethodsAn IC rat model was established by intraperitoneal injection of cyclophosphamide combined with bladder perfusion of fisetin and tumor necrosis factor-α (TNF-α) to mimic IC. An in vitro model was established using TNF-α-induced rat bladder epithelium cells. H&E staining was used to assess bladder tissue damage and ELISA was used to measure inflammatory cytokine levels. Western blot analysis was used to examine Nrf2, Bax, Bcl-2, cleaved caspase-3, p-p38, p38, p-NF-κB and NF-κB protein expression levels. RNA immunoprecipitation and RNA pull-down assays were used to examine the interaction between MEG3 and Nrf2. ResultsMEG3 levels were upregulated in IC tissues and bladder epithelial cells, whereas Nrf2 expression was found to be downregulated. Knockdown of MEG3 reduced bladder tissue injury, inflammation, oxidative stress and apoptosis. MEG3 was negatively correlated with Nrf2. Downregulation of MEG3 alleviated IC inflammation and injury by upregulating Nrf2 and inhibiting the p38/NF-κB pathway. ConclusionDownregulation of MEG3 alleviated inflammation and injury in IC rats by upregulating Nrf2 and inhibiting the p38/NF-κB pathway.

Indirect immunofluorescence on rat bladder epithelium inpatients with pemphigus vulgaris with an extended follow-up.

BackgroundIndirect immunofluorescence (IIF) on rat bladder epithelium (RBE) has been widely used to detect anti‐plakin antibodies present in paraneoplastic pemphigus (PNP). However, anti‐plakin antibodies have also been found in a group of patients with pemphigus vulgaris (PV).ObjectivesTo assess the reactivity rate of PV sera in IIF using RBE as substrate and the diagnostic usefulness of the aforementioned test.MethodsPatients diagnosed with PV presenting to Razi Hospital, Tehran, Iran, were recruited. The patients' demographics, disease severity, and response to the initial treatment were recorded. Sera were collected and tested by IIF on RBE and by desmoglein 3/1 (Dsg 3/1) enzyme‐linked immunosorbent assay. Patients were followed up closely for a mean of 53.9 months for any evidence of malignancy.ResultsForty‐six patients were enroled (mean age of 42.9 years old, 31 females). Nine sera (19.6%) showed reactivity in IIF on RBE. Mean serum anti‐Dsg levels did not differ significantly among the two groups with positive and negative IIF results. Negative anti‐Dsg3 was related to a higher positive rate in IIF on RBE. There was no significant correlation between the reactivity of IIF on RBE and patients' demographic, clinical, or serological characteristics.ConclusionsIIF on RBE is a sensitive test for detecting antibodies against plakins. However, it has a relatively high false‐positive rate in PV, probably due to the epitope spreading phenomenon. This test should be suggested when there is a clinical or immunohistopathological suspicion of PNP and should be interpreted with caution.

Effect of Conjugated Linoleic Acid (CLA) Supplementation on Expression of B-Cell Lymphoma-2 (Bcl-2) in the Bladder Epithelium of Wistar (Rattus norvegicus) Rats Exposed to Cigarette Smoke.

Bladder carcinoma is the 10th most common cancer in the world with an incidence about 3% of all cancers. The risk factor for smoking is found in 81% of all cases of bladder carcinoma. One of the protein groups associated with bladder urothelial carcinoma is B-Cell Lymphoma-2 (Bcl-2). Nicotine-derived nitrosamine ketone (NNK) contained in cigarette smoke would increase the proliferation of cancer cells through increased the expression of Bcl-2. The expression of Bcl-2 could be suppressed in the presence of Conjugated Linoleic Acid (CLA), a polyunsaturated fatty acid that has role in reducing the risk of cancer development which is reported in several studies, and then stimulate cell apoptosis. To determine the effect of CLA supplementation on Bcl-2 expression in the bladder of rats which is exposed to cigarette smoke. The study is an experimental study with true experimental posttest only control group design on Wistar rats. Sample was divided into 2 case groups: 0.5% of diet (125 mg) CLA supplementation in group A, 1% of diet (250 mg) CLA in group B; and 2 control groups: group without CLA supplementation (group C) as positive control and without cigarette smoke exposure (group D) as negative control. The study takes 60 days of exposure and then Bcl-2 expression on bladder epithelial was evaluated by immunohistochemistry staining. The results descriptively showed that rats in group C has an average Bcl-2 expression of 25.8±7.33%, while rats in group D has an average Bcl-2 expression 14.1±7.73% which means cigarette smoke exposure has been shown to increase the expression of Bcl-2 by 45.35% (p=0.019) in the bladder mucosa of experimental animals. Group B obtained an average Bcl-2 expression was 14.2±9.6% and has a significant difference when compared to group C, it shows that the addition of 1% CLA would reduce the expression of Bcl-2 by 44.96% (p=0.032). However, for group A, group with 0.5% diet of CLA supplementation did not showed decrease of Bcl-2 expression when compared to the group C (p=0.37). Conjugated Linoleic Acid (CLA) supplementation 1% of diet can reduce Bcl-2 expression in bladder epithelium of wistar rats (Rattus norvegicus) exposed to cigarette smoke.

A Case of Thymoma-Associated Paraneoplastic Pemphigus Presenting as Psoriasis

Thymoma was reported to be frequently associated with autoimmune diseases, including not only Myasthenia Gravis (MG), but also a variety of dermatoses, such as lichen planus, pemphigus vulgaris, pemphigus foliaceous, graft-vs-host disease, and Paraneoplastic Pemphigus (PNP) [1-3]. Here, we report a rare case of thymoma-associated pemphigus presenting as psoriasis. A 48-year-old man presented with pruritic skin rash all over the body for 2 months. He underwent thymectomy (type B2 thymoma) 9 years ago, followed by postoperative chemotherapy and radiotherapy, but 2 years ago, pleural metastasis was found and he developed MG, which was controlled by pyridostigmine, prednisone and plasmapheresis. Two months before, he developed pruritic skin eruptions. Physical examination revealed annular erythemas with white scales on the trunk and extremities, no oral lesion was found (Figure 1a and 1b). Laboratory examination revealed an elevated SCC antigen level of >100ng/ml (normal 0-2.5 ng/ml). ANA, anti- SSA, anti-SSB, anti-dsDNA, and anti-Sm antibodies were all negative. Histopathology showed parakeratosis, psoriasis-like epidermal hyperplasia, necrotic keratinocytes, basal cell edema and lichenoid lymphocytes infiltration (Figure 1c). DIF showed positive intercellular IgG and C3 deposition. IIF identified positive intercellular IgG on rat bladder epithelium (titer 1: 80). Anti-Dsg1 and anti-Dsg3 antibodies were normal. CT scan revealed pleural metastasis of thymoma (Figure 1d). The patient was diagnosed as PNP based on the skin eruption, histopathology, IIF of rat bladder epithelium and pleural metastasis of the thymoma [4]. The lesions relieved partly with oral prednisone 40mg/d. The patient finally died from respiratory failure within half a year.

Characterization of Urothelial Inclusions in Male Wistar Han Rats Treated Orally With the Novel α2A-Adrenoceptor Agonist Tasipimidine.

Intracellular inclusions were observed in urinary bladder epithelium of male Wistar rats, following oral treatment with high doses of the α2A-adrenoceptor agonist tasipimidine for 28 days. No cell death or inflammation was associated with the brightly eosinophilic inclusions. Electron microscopy (EM) studies showed that the inclusions represented intact or fragmented red blood cells (RBC) resulting from erythrophagocytosis, further supported by the presence of iron in urothelial cells. In addition, scattered iron-positive macrophages were observed in the submucosa and muscle layer, indicating microvascular leakage, as no major hemorrhage was evident. Despite the presence of inclusions, the urothelium showed normal uroplakin III distribution, normal cell turnover, and an absence of α-2u-globulin. It is, therefore, concluded that the inclusions were not associated with urothelial damage or increased renewal of the epithelium. This finding shows also that urothelial cells have the capability to phagocytize and break down RBCs originating from submucosal microvascular leakage. Similar changes were not observed in tasipimidine-treated beagle dogs (28 days), suggesting these findings were rat specific. The leakage of RBCs into the urothelium is suggested to be a consequence of exaggerated pharmacology leading to vasoconstriction of submucosal blood vessels in combination with transient increased bladder distension and pressure.

Pemphigus and Bullous Pemphigoid

Pemphigus disorders are characterized by acantholysis, whereas pemphigoid disorders are characterized by a dermal-epidermal split. Diagnosis of pemphigus or pemphigoid relies on a combination of positive anti-desmoglein or anti-collagen XVII serology, confirmatory direct immunofluorescence, and clinical features. Treatment for immunobullous disease revolves around various immunosuppressants, most often some combination of rituximab, prednisone, and IVIg. Paraneoplastic pemphigus is characterized by hemorrhagic crusting of the lips with positive indirect immunofluorescence on rat bladder epithelium, which should prompt a search for malignancy. Hailey-Hailey disease is a genetically mediated pemphigus that typically occurs in skin folds and responds to a number of agents including botulinum toxin, topical steroids, and other anecdotal therapies. This review contains 17 figures, 2 tables, and 109 references. Keywords: blister, pemphigus, bullous, rituximab, bullae, prednisone

Pemphigus and Bullous Pemphigoid

Pemphigus disorders are characterized by acantholysis, whereas pemphigoid disorders are characterized by a dermal-epidermal split. Diagnosis of pemphigus or pemphigoid relies on a combination of positive anti-desmoglein or anti-collagen XVII serology, confirmatory direct immunofluorescence, and clinical features. Treatment for immunobullous disease revolves around various immunosuppressants, most often some combination of rituximab, prednisone, and IVIg. Paraneoplastic pemphigus is characterized by hemorrhagic crusting of the lips with positive indirect immunofluorescence on rat bladder epithelium, which should prompt a search for malignancy. Hailey-Hailey disease is a genetically mediated pemphigus that typically occurs in skin folds and responds to a number of agents including botulinum toxin, topical steroids, and other anecdotal therapies. This review contains 17 figures, 2 tables, and 109 references. Keywords: blister, pemphigus, bullous, rituximab, bullae, prednisone

Paraneoplastic pemphigus: Retrospective study of a case series

Paraneoplastic pemphigus (PNP) is a rare condition associated with poor prognosis. It associates polymorphic mucocutaneous manifestations with neoplasia. Diagnosis is difficult because of the various clinical and histological features involved and the lack of specificity of immunological examinations. We retrospectively analyzed the records of patients presenting with PNP in the Poitou-Charentes region between 2000 and 2015. Seven patients were included. They presented 9 neoplasias (1 lymphoma, 1 melanoma, and 7 carcinomas) diagnosed from 4 months before to 25 months after the occurrence of cutaneous (6/7) and/or mucosal (6/7) polymorphic lesions. Histological examination revealed epidermal acantholysis (7/7), keratinocytic necrosis (4/7), and interface lichenoid dermatitis (5/7). Intercellular deposits of IgG and C3 or along the dermo-epidermal junction were detected with direct immunofluorescence (IF) (7/7). Four of 6 patients tested had positive indirect IF on rat bladder epithelium. Follow-up ranged from 1-132 months with a one-year survival of 85.7%. The clinical and histopathological presentations observed in our patients were polymorphic, with overlap between the clinical and histological features of PNP and classical pemphigus. Prognosis and survival appear better in our series than in the literature. It is possible that in some cases, the association of pemphigus with neoplasia was fortuitous, which might account for the better prognosis. A new consensus on the diagnostic criteria for PNP is needed to help practitioners to consensually diagnose it for prognostic or therapeutic trials.

γ-H2AX formation in the urinary bladder of rats treated with two norharman derivatives obtained from o-toluidine and aniline.

Aminomethylphenylnorharman (AMPNH) and aminophenylnorharman (APNH) are mutagenic norharman derivatives obtained from o-toluidine and aniline, respectively. APNH is carcinogenic to the urinary bladder of rats and present in urine samples of healthy volunteers, indicating that norharman derivatives may be associated with cancer development in the urinary bladder of humans. To evaluate the possible role of AMPNH and APNH in bladder carcinogenesis, we examined the formation of γ-H2AX, a DNA damage response marker, in the urinary bladder of rats. Seven-week-old male F344 rats were treated with 400ppm AMPNH or 40ppm APNH in the diet for 4weeks. Animals were killed at the end of administration or after 2weeks of recovery, and immunohistochemistry for γ-H2AX and Ki67, a cell proliferation marker, was performed. At week 4, γ-H2AX formation in bladder epithelial cells was significantly increased by APNH treatment as compared with that in controls. AMPNH also induced upregulation of γ-H2AX formation, although there was no statistical significance. After the recovery period, γ-H2AX-positive cells were reduced but remained significantly higher in AMPNH and APNH groups than in the control group. Ki67-positive cells were significantly increased by AMPNH and APNH at week 4 and reduced to the same level as the control after 2weeks of recovery. Expression of KRT14, a bladder stem cell marker, was also increased in the basal layer by the two norharman derivatives. Thus, AMPNH and APNH showed in vivo genotoxicity in the bladder epithelium of rats, and APNH may be a potent causative agent of bladder carcinogenesis.

Castration increases PGE2 release from the bladder epithelium in male rats

AimsAndrogen deprivation therapy has been widely used for the treatment of prostate cancer. While sexual side effects including decreased sexual desire and function are well studied, there are only limited reports about its influences on lower urinary tract symptoms. The aim of this study is to clarify the influences of castration in male rats. MethodsTen-week-old male rats were divided into treatment group (bilateral orchiectomy) and control group (sham surgery). Two-months after the surgery, adenosine triphosphate (ATP), prostaglandin E2 (PGE2), and nerve growth factor (NGF) released from stretched bladder epithelium were measured by luciferin-luciferase assay or ELISA. The mRNA levels of bladder cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) were determined by real-time PCR. The protein level of bladder COX-2 was analyzed by western blot analysis. Bio-Plex Pro cytokine assay was performed to quantify the level of proinflammatory cytokine interleukin (IL)-1β in the bladder. ResultsThe PGE2 release from stretched bladder epithelium was significantly increased after castration, which increased more than 50% compared with control. On the other hand, those of ATP and NGF were not different from those of the controls. Testosterone replacement restored the PGE2 increase. Castration significantly increased bladder IL-1β protein level and COX-2 at both mRNA and protein levels, whereas caused no marked changes in the COX-1 mRNA level. ConclusionsThese findings suggest that castration induces inflammation in the rat bladder, which causes elevated PGE2 release from bladder epithelium and may finally contribute to the disruption of bladder storage function.

High salt loading induces urinary storage dysfunction via upregulation of epithelial sodium channel alpha in the bladder epithelium in Dahl salt-sensitive rats

We aimed to investigate whether high salt intake affects bladder function via epithelial sodium channel (ENaC) by using Dahl salt-resistant (DR) and salt-sensitive (DS) rats. Bladder weight of DR + high-salt diet (HS, 8% NaCl) and DS + HS groups were significantly higher than those of DR + normal-salt diet (NS, 0.3% NaCl) and DS + NS groups after one week treatment. We thereafter used only DR + HS and DS + HS group. Systolic and diastolic blood pressures were significantly higher in DS + HS group than in DR + HS group after the treatment period. Cystometrogram showed the intercontraction intervals (ICI) were significantly shorter in DS + HS group than in DR + HS group during infusion of saline. Subsequent infusion of amiloride significantly prolonged ICI in DS + HS group, while no intra-group difference in ICI was observed in DR + HS group. No intra- or inter-group differences in maximum intravesical pressure were observed. Protein expression levels of ENaCα in the bladder were significantly higher in DS + HS group than in DR + HS group. ENaCα protein was localized at bladder epithelium in both groups. In conclusion, high salt intake is considered to cause urinary storage dysfunction via upregulation of ENaC in the bladder epithelium with salt-sensitive hypertension, suggesting that ENaC might be a candidate for therapeutic target for urinary storage dysfunction.

Examination of in vivo mutagenicity of sodium arsenite and dimethylarsinic acid in gpt delta rats

Arsenic is a well-known human bladder and liver carcinogen, but its exact mechanism of carcinogenicity is not fully understood. Dimethylarsinic acid (DMAV) is a major urinary metabolite of sodium arsenite (iAsIII) and induces urinary bladder cancers in rats. DMAV and iAsIII are negative in in vitro mutagenicity tests. However, their in vivo mutagenicities have not been determined. The purpose of present study is to evaluate the in vivo mutagenicities of DMAV and iAsIII in rat urinary bladder epithelium and liver using gpt delta F344 rats. Ten-week old male gpt delta F344 rats were randomized into 3 groups and administered 0, 92mg/L DMAV, or 87mg/L iAsIII (each 50mg/L As) for 13weeks in the drinking water. In the mutation assay, point mutations are detected in the gpt gene by 6-thioguanine selection (gpt assay) and deletion mutations are identified in the red/gam genes by Spi− selection (Spi− assay). Results of the gpt and Spi− assays showed that DMAV and iAsIII had no effects on the mutant frequencies or mutation spectrum in urinary bladder epithelium or liver. These findings indicate that DMAV and iAsIII are not mutagenic in urinary bladder epithelium or liver in rats.

Aldehyde dehydrogenase induction in arsenic-exposed rat bladder epithelium

Arsenic is widely distributed in the environment. Many human cancers, including urothelial carcinoma (UC), show a dose-dependent relationship with arsenic exposure in the south-west coast of Taiwan (also known as the blackfoot disease (BFD) areas). However, the molecular mechanisms of arsenic-mediated UC carcinogenesis has not yet been defined. In vivo study, the rat bladder epithelium were exposed with arsenic for 48h. The proteins were extracted from untreated and arsenic-treated rat bladder cells and utilized two-dimensional gel electrophoresis and mass spectrometry. Selected peptides were extracted from the gel and identified by quadrupole-time of flight (Q-TOF) Ultima-Micromass spectra. The significantly difference expression of proteins in arsenic-treated groups as compared with untreated groups was confirmed by immunohistochemistry (IHC) and western blotting. We found that thirteen proteins were down-regulated and nine proteins were up-regulated in arsenic-treated rat bladder cells when compared with untreated groups. The IHC and western blotting results confirmed that aldehyde dehydrogenase (ALDH) protein was up-regulated in arsenic-treated rat bladder epithelium. Expression of ALDH protein was significantly higher in UC patients from BFD areas than those from non-BFD areas using IHC (p=0.018). In conclusion, the ALDH protein expression could be used as molecular markers for arsenic-induced transformation.

DMA(V) in Drinking Water Activated NF-κB Signal Pathway and Increased TGF-β and IL-1β Expressions in Bladder Epithelial Cells of Rats.

Dimethylarsinic acid (DMAV) is the main product of arsenic methylation metabolism in vivo and is rat bladder carcinogen and tumor promoting agent. In this study, we measured the expressions of mRNA and proteins of NF-κB pathway members, IKKα, IKKβ, p65, and p50 in rat bladder epithelium by qRT-PCR and immunohistochemical analysis after rats received drinking water containing 100 and 200 ppm DMAV for 10 weeks. Transforming growth factor-β (TGF-β) immunoexpression in rat bladder epithelium and urine level of IL-1β also were determined. We found that DMAV dramatically increased the mRNA levels of NF-κB p50 and IKKα in the bladder epithelium of rats compared to the control group. Immunohistochemical examinations showed that DMAV increased immunoreactivities of IKKα, IKKβ, and phospho-NF-κB p50 in the cytoplasm and phospho-NF-κB p50 and p65 in nucleus of rat urothelial cells. In addition, DMAV treated rats exhibited significantly increased inflammatory factor TGF-β immunoreactivity in bladder epithelium and IL-1β secretion in urine. These data suggest that DMAV could activate NF-κB signal pathway and increase TGF-β and IL-1β expressions in bladder epithelial cells of rats.

Effects of co-administration of dietary sodium arsenate and 2,3-dimercaptopropane-1-sulfonic acid (DMPS) on the rat bladder epithelium

Inorganic arsenic is a known human carcinogen, inducing tumors of the skin, urinary bladder and lung. It is metabolized to organic methylated arsenicals. 2,3-Dimercaptopropane-1-sulfonic acid (DMPS), a chelating agent, is capable of reducing pentavalent arsenicals to the trivalent state and binding to the trivalent species, and it has been used in the treatment of heavy metal poisoning in humans. Therefore, we investigated the ability of DMPS to inhibit the cytotoxicity and regenerative urothelial cell proliferation induced by arsenate administration in vivo. Female rats were treated for 4 weeks with 100ppm AsV. DMPS (2800ppm) co-administered in the diet significantly reduced the AsV-induced cytotoxicity of superficial cells detected by scanning electron microscopy (SEM), and the incidence of simple hyperplasia observed by light microscopy and the bromodeoxyuridine (BrdU) labeling index. It also reduced the total concentration of arsenicals in the urine and the methylation of arsenic. There were no differences in oxidative stress as assessed by immunohistochemical staining for 8-hydroxy-2′-deoxyguanosine (8OHdG) of the bladder urothelium. No differences were detected in urine sediments between groups. These data suggest that DMPS has the ability to inhibit both arsenate-induced acute toxicity and regenerative proliferation of the rat bladder epithelium, most likely by decreasing exposure of the urothelium to trivalent arsenicals excreted in the urine. These data provide additional evidence that the effects of arsenate exposure in vivo do not appear to be related to oxidative effects on dG in DNA.

Analysis of the reactivity of indirect immunofluorescence in patients with pemphigus foliaceus and pemphigus vulgaris using rat bladder epithelium as a substrate

OBJECTIVES:To evaluate the reactivity of indirect immunofluorescence using rat bladder epithelium as a substrate in patients with pemphigus foliaceus and pemphigus vulgaris from the Department of Dermatology, University of São Paulo Medical School, Brazil.METHODS:Thirty-two patients (8 male and 24 female) from the Department of Dermatology, University of São Paulo Medical School, were selected. Three had mucosal pemphigus vulgaris, 20 had mucocutaneous pemphigus vulgaris, and 9 had pemphigus foliaceus. Patients' sera were tested by indirect immunofluorescence performed on human foreskin and rat bladder epithelium and by ELISA assays utilizing baculovirus-expressed recombinant desmoglein 3 and desmoglein 1.RESULTS:No patients with mucosal pemphigus vulgaris, 5 of 20 patients with mucocutaneous pemphigus vulgaris (25%) and 4 of 9 patients with pemphigus foliaceus (44%) had positive indirect immunofluorescence using rat bladder epithelium as a substrate.CONCLUSION:Indirect immunofluorescence using rat bladder epithelium as a substrate is recommended whenever a diagnosis of paraneoplastic pemphigus is considered. The identification of a subset of pemphigus foliaceus and pemphigus vulgaris patients that recognizes desmoplakins by this laboratory tool is critical to avoid the misdiagnosis of paraneoplastic pemphigus.

Analysis of the reactivity of indirect immunofluorescence in patients with pemphigus foliaceus and pemphigus vulgaris using rat bladder epithelium as a substrate

Analysis of the reactivity of indirect immunofluorescence in patients with pemphigus foliaceus and pemphigus vulgaris using rat bladder epithelium as a substrate

Effects of co-administration of dietary sodium arsenite and an NADPH oxidase inhibitor on the rat bladder epithelium

Arsenite (As III), an inorganic arsenical, is a known human carcinogen, inducing tumors of the skin, urinary bladder and lung. It is metabolized to organic methylated arsenicals. Oxidative stress has been suggested as a mechanism for arsenic-induced carcinogenesis. Reactive oxygen species (ROS) can be important factors for carcinogenesis and tumor progression. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is known to produce intracellular ROS, therefore, we investigated the ability of apocynin (acetovanillone), an NADPH oxidase inhibitor, to inhibit the cytotoxicity and regenerative cell proliferation of arsenic in vitro and in vivo. Apocynin had similar effects in reducing the cytotoxicity of As III and dimethylarsinous acid (DMA III) in rat urothelial cells in vitro. When tested at the same concentrations as apocynin, other antioxidants, such as l-ascorbate and N-acetylcysteine, did not inhibit As III-induced cytotoxicity but they were more effective at inhibiting DMA III-induced cytotoxicity compared with apocynin. In vivo, female rats were treated for 3 weeks with 100 ppm As III. Immunohistochemical staining for 8-hydroxy-2′-deoxyguanosine (8-OHdG) showed that apocynin reduced oxidative stress partially induced by As III treatment on rat urothelium, and significantly reduced the cytotoxicity of superficial cells detected by scanning electron microscopy (SEM). However, based on the incidence of simple hyperplasia and the bromodeoxyuridine (BrdU) labeling index, apocynin did not inhibit As III-induced urothelial cell proliferation. These data suggest that the NADPH oxidase inhibitor, apocynin, may have the ability to partially inhibit arsenic-induced oxidative stress and cytotoxicity of the rat bladder epithelium in vitro and in vivo. However, apocynin did not inhibit the regenerative cell proliferation induced by arsenite in a short-term study.

Effects of an epidermal growth factor receptor inhibitor on arsenic associated toxicity in the rat bladder epithelium

Arsenite (As(III)), an inorganic arsenical, is a known human carcinogen, inducing tumors of the skin, urinary bladder and lung. It is known to be metabolized to organic methylated arsenicals in vivo. As(III) has been reported to have the ability to up-regulate the epidermal growth factor receptor (EGFR)-associated pathway in epithelial cells, including human urothelial cells in vitro. EGFR is a cell-surface receptor belonging to the ErbB family of receptor tyrosine kinases, and the EGFR-associated signaling pathway has been reported to play an important role in carcinogenesis and cancer progression, including in bladder cancer. In this study, we investigated the growth effects of As(III) and an organic trivalent arsenical, dimethylarsinous acid (DMA(III)), and the effects of co-exposure of gefitinib, an EGFR inhibitor, with As(III) to a rat urothelial cell line (MYP3). We also investigated the effects of co-administration of dietary As(III) and gefitinib in vivo. In vitro, concentrations of 1.0microM As(III) or 0.5microM DMA(III) induced cytotoxicity. However, lower concentrations of As(III) treatment had a slight mitogenic growth effect whereas lower concentrations of DMA(III) did not. Gefitinib blocked As(III)-induced cell growth in vitro. In vivo, a high dose of gefitinib alone induced slight urothelial cytotoxicity, and did not reduce cytotoxicity and regenerative cell proliferation when co-administered with As(III). The majority of arsenic metabolites present in the urine of As(III)-treated rats were organic arsenicals, mainly dimethylarsinic acid (DMA(V)). As(III) was also present, and its concentration was higher than the concentration required to produce cytotoxicity in vitro. These data suggest that an EGFR inhibitor has the ability to block As(III)-induced cell proliferation in vitro but not in vivo in a short-term study.