Human AKR1A1 involves in metabolic activation of carcinogenic aristolochic acidⅠ

OBJECTIVE To investigate whether aldo-keto reductases(AKRs)can act as a nitrore⁃ductase(NR)and bioactivate aristolochic acidⅠ(AA-Ⅰ)to produce AA-Ⅰ-DNA adducts.METHODS①Human-induced hepatocytes(hiHeps)and human bladder RT4 cells were used as tool cells and treated with AA-Ⅰ0,0.5,1.0 and 2μmol·L^(-1)for 24 h.Cell viability was detected using the CCK-8 method,and the half maximal inhibition concentration(IC_(50))was calculated using the CCK-8 method and the level of DNA adduct production was calculated.②hiHeps and RT4 cells were treated with AKR inhibitor luteotin(0,5,10 and 25μmol·L^(-1))+AA-Ⅰ0.2 and 1.0μmol·L^(-1)for 24 h,respectively,and the levels of DNA adducts were detected by a liquid chromatography-tandem mass spectrometer(LC-MS/MS).③hiHeps cells were incubated with 80 nmol·L^(-1)small interfering RNAs(si-AKRs)for 48 h and treated with AA-Ⅰ1.0μmol·L^(-1)for 24 h.Real-time qualitative PCR(RT-qPCR)method was used to detect the mRNA expression of AKRs gene and LC-MS/MS technology was used to investigate the effect of specific AKR gene knockdown on DNA adduct levels.④500 nmol·L^(-1)human AKR recombinant proteins AKR1A1 and AA-Ⅰwere incubated in vitro under anaerobic conditions and the formation of AA-Ⅰ-DNA adducts was detected.RESULTS①The IC_(50)of AA-Ⅰto hiHeps and RT4 cells was 1.9 and 0.42μmol·L^(-1),respec⁃tively.The level of DNA adduct production of the two cell lines was significantly different(P<0.01).②Luteolin≥5μmol·L^(-1)significantly inhibited the production of AA-Ⅰ-DNA adducts in both cells(P<0.05),and there was a concentration-dependent effect in hiHeps cells(P<0.01,R=0.84).③In the AKR family,the knockdown of AKR1A1 gene up to 80%inhibited the generation of AA-Ⅰ-DNA adducts by 30%-40%.④The AA-Ⅰ-DNA adducts were detected in the incubation of recombinant protein AKR1A1 and AA-Ⅰunder anaerobic conditions in vitro,approximately 1 adduct per 107 nucleotides.CONCLU⁃SION AKR1A1 is involved in AA-Ⅰbioactivation,providing a reference for elucidation of the carcino⁃genic mechanism of AA-Ⅰ.

Nephrotoxicity and carcinogenesis of aristolochic acids and their derivates

Aristolochic acids （AAs）, a natural mixture of 8-methoxy-6-nitro-phenanthro-（3,4-d）-1,3-dioxolo-5-carboxylic acid （AAI）and 6-nitro-phenanthro-（3,4-d）-1,3-dioxolo-5-carboxylic acid （AAII）, derived from aristolochiaceae species, has beenreported to cause AAS-induced nephropathy and upper urothelial cancer. In this review, we summarize the informationon the nephrotoxicity and carcinogenesis of AAs and their derivatives. AAs nephrotoxicity can lead to apoptosis andoxidative stress of renal tubular cells, and inhibition of the expression of aquaporins. AAs can also reduce the capabilityfor renal tubular epithelial cell repair after acute injury and further produce renal fibrosis by activating TGF-β-Smadsignaling and promoting the migration of macrophages. Moreover, AAs-induced carcinogenesis may be due to theformation of covalent adducts with DNA which can lead to the mutation in certain tumor suppressor genes orproto-oncogenes and the different catalyzing capacity of the microsomal cytochrome P450 of individuals in AAImetabolism.

EFFECTS OF PROSTAGLANDIN E1 ON THE PROGRESSION OF ARISTOLOCHIC ACID NEPHROPATHY

Objective To investigate the effects of prostaglandin E1 (PGE1) on the progression of aristolochic acid nephropathy (AAN). Methods Twenty-four patients diagnosed as AAN with serum creatinine (Scr) between 1.5 mg/dL and 4 mg/dL during September 2001 to August 2003 were randomly divided into 2 groups. All patients had ingested long dan xie gan wan con-taining aristolochic acid (0.219 mg/g) for at least 3 months. Twelve patients were injected with Alprostadil (10 μg/d for 10 days in one month, summing up to 6 months). Except for PGE1, the other therapy was same in both groups. Renal function was assessed using reciprocal serum creatinine levels (1/Scr). Results The level of Scr and serum hemoglobin (Hgb) was similar in both groups prior to therapy. During follow-up, 1/Scr levels in PGE1 group were significantly higher than control group (P < 0.01), and Hgb levels in PGE1 group were sig-nificantly increased compared with control (P < 0.05).Conclusion PGE1 can slow the progression of renal failure and increase Hgb level of AAN patient.

NMR Studies on the Subacute Biochemical Effects of Aristolochic Acid on Rat Serum

The subacute effect of aristolochic acid （AA） on rat serum was studied by NMR method. The biochemical effects induced by AA were characterized by an increase in the amounts of creatinine, trimethylamine N-oxide, acetoacetate, acetate and 3-D-hydroxybutyrate and lactate in serum from ^1H NMR spectra. Principal component analysis was used for further comparing the similarities of ^1H NMR spectral profiles of serum from rats treated with AA and model toxins.

Improved preparation and identification of aristolochic acid-DNA adducts by solid-phase extraction with liquid chromatography-tandem mass spectrometry

Aristolochic acid （AA） is a known nephrotoxin and potential carcinogen, which can form covalent DNA adducts after metabolic activation in vivo and in vitro. A simple method for preparation and characterization of aristolochic acid-DNA adducts was developed. Four AA-adducts were synthesized by a direct reaction of AAI/AAII with 2′-deoxynucleosides. The reaction mixture was first cleaned-up and pre-concentrated using solid phase extraction （SPE）, and further purified by a reversed-phase high performance liquid chromatography （HPLC）. By the application of developed SPE procedure, matrices and byproducts in reaction mixture could be greatly reduced and adducts of high purity （more than 94% as indicated by HPLC） were obtained. The purified AA-DNA adducts were identified and characterized with liquid-electrospray ionization-quadrupole-time of flight-mass spectrometry （LC-ESI-Q-TOF-MS/MS） and LC-Diode array detector-fluorescence （LC-DAD-FL） analysis. This work provides a robust tool for possible large-scale preparation of AA-DNA adduct standards, which can promote the further studies on carcinogenic and mutagenic mechanism of aristolochic acids.

Electrochemistry of aristolochic acid interacting with guanine

Interaction of Aristolochic acid （AA） and guanine （G） was studied by electrochemical techniques in this paper. When AA was added into the guanine solution, the oxidation peak currents of mixture solution decreased, while the peak potential and the electrochemical kinetic parameters remained the same as when AA was absent, except that the electrode process of guanine that involved two protons and two electrons changed from adsorption controlled to diffusion controlled. It is suggested that an electrochemical inactive supramolecular adduct AA-Gua （1：1） was formed in the system. The adduct cannot be oxidized on the glassy carbon electrode, which indirectly results in the decrease of the free concentration of guanine in the reaction solution and the decrease of peak currents. The binding constant （13） of this adduct is calculated as 7.14× 10^3 mol/L. The possible mechanism for the interaction of Aristolochic acid and DNA was proposed, that may provide a possible pathway for the nosogenesis research of aristolochic acid.

A NEW ARISTOLOCHIC ACID FROM ARISTOLOCHIA CINNABARINA

A new compound, aristolochoc acid Ⅲ a- 6-0-β-D-glucoside, was isolated along with four known compounds from Aristolochia cinnabarina. The structure of the new,compound was elucidated on the basis of spectral evidences

Chemical profiling of principle active and toxic constituents in herbs containing aristolochic acids

Objective:To clear the amounts of the principal active/toxic components in herbs containing aristolochic acids(HCAAs),which are still used as medicine and/or seasoning in many ethnic minority areas of China.Methods:In this study,six major active and toxic components in HCAAs were extracted with ultrasonic extraction.With 6-O-methyl guanosine as internal standard,the target compounds were analyzed qualitatively and quantitatively by using ultrahigh performance liquid chromatography-electrospray ionization-tandem mass spectrometry(UPLC-ESI-MS/MS)with multiple reaction monitoringinformation dependent acquisition-enhanced production ion scanning mode(MRM-IDA-EPI)combined with dynamic background subtraction(DBS)function.Results:The method showed good linearity in the linear range of the six analytes.The limit range of detection was from 0.01 ng/mL to 0.27 ng/mL.All of the detection repeatability,extraction repeatability and accuracy of the method were good.After extraction,the samples remained stable at 15℃ within 24 h.Six analytes were all found in samples except aristolactam(AL)in sample 2,and the contents varied greatly.The contents of these compounds decreased in fruits,leaves and stems of Aristolochia delavayi successively.Conclusion:This method has the advantages of less sample dosage,simple operation,short analysis cycle,high sensitivity,specificity and accuracy.It laid a good foundation for guiding the safety of HCAAs,the indepth study of pharmacological and toxicological effects and the scientific and standardized processing and compatibility of HCAAs.

No Incidence of Liver Cancer Was Observed in A Retrospective Studyof Patients with Aristolochic Acid Nephropathy

Objective:To assess the risk of aristolochic acid(AA)-associated cancer in patients with AA nephropathy(AAN).Methods:A retrospective study was conducted on patients diagnosed with AAN at Peking University First Hospital from January 1997 to December 2014.Long-term surveillance and follow-up data were analyzed to investigate the influence of different factors on the prevalence of cancer.The primary endpoint was the incidence of liver cancer,and the secondary endpoint was the incidence of urinary cancer during 1 year after taking AA-containing medication to 2014.Results:A total of 337 patients diagnosed with AAN were included in this study.From the initiation of taking AA to the termination of follow-up,39 patients were diagnosed with cancer.No cases of liver cancer were observed throughout the entire follow-up period,with urinary cancer being the predominant type(34/39,87.17%).Logistic regression analysis showed that age,follow-up period,and diabetes were potential risk factors,however,the dosage of the drug was not significantly associated with urinary cancer.Conclusions:No cases of liver cancer were observed at the end of follow-up.However,a high prevalence of urinary cancer was observed in AAN patients.Establishing a direct causality between AA and HCC is challenging.

Activation of LONP1 by 84-B10 alleviates aristolochic acid nephropathy via re-establishing mitochondrial and peroxisomal homeostasis

Pharmaceutical formulations derived from Aristolochiaceae herbs, which contain aristolochic acids(AAs), are widely used for medicinal purposes. However, exposure to these plants and isolated AAs is linked to renal toxicity, known as AA nephropathy(AAN). Currently, the mechanisms underlying AAN are not fully understood, leading to unsatisfactory treatment strategies. In this study, we explored the protective role of 84-B10(5-[[2-(4-methoxyphenoxy)-5-(trifluoromethyl) phenyl] amino]-5-oxo-3-phenylpentanoic acid) against AAN. RNA-seq analysis revealed that the mitochondrion and peroxisome were the most affected cellular components following 84-B10 treatment in AAN mice. Consistently, 84-B10 treatment preserved mitochondrial ultrastructure, restored mitochondrial respiration, enhanced the expression of key transporters(carnitine palmitoyltransferase 2) and enzymes(acylCoenzyme A dehydrogenase, medium chain) involved in mitochondrial fatty acid β-oxidation, and reduced mitochondrial ROS generation in both aristolochic acid I(AAI)-challenged mice kidneys and cultured proximal tubular epithelial cells. Additionally, 84-B10 treatment increased the expression of key transporters(ATP binding cassette subfamily D) and rate-limiting enzymes(acyl-CoA oxidase 1) involved in peroxisomal fatty acid β-oxidation and restored peroxisomal redox balance. Knocking down LONP1 expression diminished the protective effects of 84-B10 against AAN, suggesting LONP1-dependent protection. In conclusion, our study provides evidence that AAN is associated with significant disturbances in both mitochondrial and peroxisomal functions. The LONP1 activator 84-B10 demonstrates therapeutic potential against AAN, likely by maintaining homeostasis in both mitochondria and peroxisomes.

Pharmacokinetica studies of aristolochic acid-I and-II in rats after intragastrical administration of Radix Aristolochiae and Muskone

The pharmacokinetic parameters of aristolochic acid-Ⅰ （AA-Ⅰ） and -Ⅱ （AA-Ⅱ） in rat serum after intragastrical administration of the crude drug powders of Radix Aristolochiae （RA） and Muskone containing equal amounts of RA were compared. The pharmacokinetic profiles of AA-Ⅰ and AA-Ⅱ could be fitted with a two-compartment model The elimination half time （T1/2β） of AA-Ⅰ in Muskone was 1573.2 min and that of AA-Ⅰ in RA was 475.8 min; T1/2β of AA-Ⅱ in Muskone was 2344.8 min and that of AA-Ⅱ in RA was 427.8 rain. The area under the concentration-time curve （AUC） of AA-Ⅰ in Muskone was 13.07 μg/h/mL and that of AA-Ⅰ in RA was 3.86 μg/h/mL; AUC of AA-Ⅱ in Muskone was 67.67 μg/h/mL and that of AA-Ⅱ in RA was 23.93 μg/h/mL. The bioavailabilities of AA-Ⅰ and AA-Ⅱ in Muskone were markedly increased compared with that in RA based on the elimination half-time and A UC values.

Rapid determination of eight aristolochic acid analogues in five Aristolochiaceae plants by ultra-high performance liquid chromatography quadrupole/time-of-flight mass spectrometry

Aristolochic acids （AAs） and aristololactams （ALs） are commonly found in some Aristolochiaceae plants, and they have been reported to be AA nephropathy （AAN）, nephrotoxicity and carcinogenicity. In the present study, we established an ultra high performance liquid chromatography （UHPLC） coupled with quadmpole/time-of-flight mass spectrometry （Q/TOF-MS） method for the rapid analysis of eight AA analogues in 19 samples originated from the five Aristolochiaceae plants, the roots and rhizomes ofAsarum sieboldii Miq. var. seoulense Nakai, the fruits ofAristolochia contorta Bunge or A. debilis Sieb. et Zucc., the roots ofAristolochia debilis Sieb. et Zucc., the stems ofAristolochia manshuriensis Kom., and the roots of Aristolochiafangchi Y. C. Wu ex L. D. Chou et S. M. Hwang. A total of five AAs and three ALs were identified by co-chromatography of sample extract and comparing the retention time, UV spectra, and characteristic molecular ions and fragment ions with those of authentic standards, or tentatively identified by MS/MS determination along with Mass Fragment software. Moreover, the method was validated for the simultaneous quantification or semi-quantification of them. The samples significantly differed in the quality and quantity of AA analogues, which aUowed the possibility of showing their chemical distinctness, and it might be helpful in their standardization and quality control. Furthermore, in order to holistically compare the difference between the five Aristolochiaceae plants, dataset obtained from UHPLC-Q/TOF-MS was processed with principal component analysis （PCA） and orthogonal partial least squared discriminant analysis （OPLS-DA）.

In situ metabolomics in nephrotoxicity of aristolochic acids based on air flow-assisted desorption electrospray ionization mass spectrometry imaging

Understanding of the nephrotoxicity induced by drug candidates is vital to drug discovery and development.Herein,an in situ metabolomics method based on air flow-assisted desorption electrospray ionization mass spectrometry imaging(AFADESI-MSI)was established for direct analysis of metabolites in renal tissue sections.This method was subsequently applied to investigate spatially resolved metabolic profile changes in rat kidney after the administration of aristolochic acid I,a known nephrotoxic drug,aimed to discover metabolites associated with nephrotoxicity.As a result,38 metabolites related to the arginine-creatinine metabolic pathway,the urea cycle,the serine synthesis pathway,metabolism of lipids,choline,histamine,lysine,and adenosine triphosphate were significantly changed in the group treated with aristolochic acid I.These metabolites exhibited a unique distribution in rat kidney and a good spatial match with histopathological renal lesions.This study provides new insights into the mechanisms underlying aristolochic acids nephrotoxicity and demonstrates that AFADESI-MSI-based in situ metabolomics is a promising technique for investigation of the molecular mechanism of drug toxicity.

Analysis of aristolochic acids, aristololactams and their analogues using liquid chromatography tandem mass spectrometry

More than 80 aristolochic acids(AAs) and aristololactams(ALs) have been found in plants of the Aristolochiaceae family, but relatively few have been fully studied. The present study aimed at developing and validating a liquid chromatography tandem mass spectrometry(LC/MS^n) for the analysis of these compounds. We characterized the fragmentation behaviors of 31 AAs, ALs, and their analogues via high performance liquid chromatography coupled with electrospray ionization mass spectrometry. We summarized their fragmentation rules and used these rules to identify the constituents contained in Aristolochia contorta, Ar. debilis, Ar. manshurensis, Ar. fangchi, Ar. cinnabarina, and Ar. mollissima. The AAs and ALs showed very different MS behaviors. In MS1 of AAs, the characteristic pseudomolecular ions were [M + NH_4]^+, [M + H]^+, and [M + H - H_2O]^+. However, only [M + H]^+ was found in the MS1 of ALs, which was simpler than that of AAs. Distinct MSn fragmentation patterns were found for AAs and ALs, showing the same skeleton among the different substituent groups. The distribution of the 31 constituents in the 6 species of Aristolochia genus was reported for the first time. 25 Analogues of AAs and ALs were detected in this genus. A hierarchical schemes and a calculating formula of the molecular formula of these nitrophenanthrene carboxylic acids and their lactams were proposed. In conclusion, this method could be applied to identification of similar unknown constituents in other plants.

Characterization and quantitation of aristolochic acid analogs in different parts of Aristolochiae Fructus, using UHPLC-Q/TOF-MS and UHPLC-Qq Q-MS

Aristolochiae Fructus, a Chinese herbal medicine derived from the fruit of Aristolochia contorta Bge., contains nephrotoxic aristolochic acid analogues(AAAs). According to ancient medical texts, various medicinal parts of the fruit of A. contorta were ever used. In order to reveal which part could be safely and effectively used, it is necessary to analyze the chemical profiles of different medicinal parts. Herein we compared the chemical compositions and determined aristolochic acid I(AA-I) and aristolochic acid II(AA-II) in the four parts viz. outer pericarp, inner pericarp, septum, and seed. Ultra-high performance liquid chromatography equipped with quadrupole time-of-flight mass spectrometry(UHPLC-QTOF-MS) was applied for chemical profiling. Ultra-high performance liquid coupled with triple quadrupole mass spectrometry(UHPLC-Qq Q-MS) was employed to quantify AA-I and AA-II in different parts. It was found that the chemical compositions of the four parts varied both qualitatively and quantitatively. A total of 10 AAAs, including 5 aristolochic acids and 5 aristolactams, together with 3 alkaloids, were unambiguously or tentatively identified by UHPLC-QTOF-MS. The quantitatively analytical results obtained by UHPLC-Qq Q-MS showed that AA-I and AA-II exclusively accumulate in the seeds of A. contorta. These findings provide supporting data for the rational selection of medicinal parts.

AristolochicacidI inducedapoptosisinLLC PK1cellsandameliorationoftheapoptoticdamagebycalciumantagonist

To examine the effect of different concentrations of aristolochic acid I (AAI) in inducing apoptosis of cultured porcine renal cell line LLC PK1 and to investigate the relationship between intracellular free calcium concentration ([Ca ++ ]i) and LLC PK1 apoptosis induced by AAI and the influence of a calcium antagonist, lacidipine on apoptosis and [Ca ++ ]i Methods LLC PK1 cells were treated in different groups: a the normal group without treatment; b the group with AAI alone (0 01?g·L 1 , 0 02?g·L 1 , 0 04 ?g·L 1 , 0 08?g·L 1 ); c the group with lacidipine alone (10?ng·L 1 , 10 2 ?ng·L 1 , 10 3?ng·L 1 ); d the group with AAI (0 04?g·L 1 ) plus lacidipine (10?ng·L 1 , 10 2? ng·L 1 , 10 3?ng·L 1 ) Light microscopy, agarose gel electrophoresis, Annexin V Flous apoptosis detection kit and flow cytometry using propidium iodide staining to identify or quantify the apoptosis of LLC PK1 cells Mean [Ca ++ ]i was measured by laser confocus microscopy using Fluo 3/AM staining Results A series of morphologic changes that were characteristic of apoptosis, Annexin V Flous staining positive apoptotic cells and “DNA ladder' were identified in AAI (0 02?g·L 1 -0 08?g·L 1 ) treated LLC PK1 cells Quantitative analysis of apoptotic cells showed that the percentage of apoptotic cells in AAI (0 02?g·L 1 , 0 04?g·L 1 or 0 08?g·L 1 ) group was significantly higher than that in normal group (5 3%, 48 5%, 78 7% vs 2 6%, P <0 001) Mean [Ca ++ ]i was significantly higher in cells treated with AAI (0 04?g·L 1 ) than that in normal cells (58 01±18 89 vs 22 66±4 78, P <0 001) In group treated with AAI plus lacidipine (102?ng·L 1 , 103?ng·L 1 ), mean [Ca ++ ]i was significantly lower than that treated with AAI alone (35 47±12 85, 28 55±10 16 vs 58 01±18 89, P <0 001) And the percentage of apoptotic cells in group treated with AAI plus lacidipine (10 2?ng·L 1 , 10 3?ng·L 1 ) was also significantly lower than that treated with AAI alone (19 0%, 27 8% vs 34 7%, P <0 001) Conclusions High concentrations of AAI may induce apoptosis of LLC PK1 cells The mean [Ca ++ ]i in AAI treated LLC PK1 cells was increased significantly, sugguesting that the increase of [Ca ++ ]i may be related to apoptosis in LLC PK1 cells Lacidipine may decrease the raised mean [Ca ++ ]i levels caused by AAI and the percentage of apoptotic cells, and lacidipine may ameliorate AAI induced apoptotic damage by inhibiting the increase of [Ca ++ ]i in LLC PK1 cells

Transitional cell carcinoma associated with aristolochic acid nephropathy： most common cancer in chronic hemodialysis patients in China

Background The research of cancer in patients on hemodialysis （HD） in China has not been reported. The aim of this study was to investigate the clinical and histological features and outcomes of cancer in Chinese HD patients. Methods The study subjects were 49 cancer patients （1.4%） out of 3448 end stage renal disease （ESRD） patients maintained on HD at China-Japan Friendship Hospital from October 1997 to July 2011. Results Urinary tract cancer （74%） was the most common followed by gastrointestinal tract cancer （12%）, breast cancer （6%）, lung cancer （4%）, thyroid cancer （2%）, and hematologic cancer （2%）. Thirty-three patients （67%） had urinary tract transitional cell carcinoma （TCC） and 29 of them had aristolochic acid nephropathy （AAN） as underlying disease. Death occurred in eight patients out of 49, and the survival rate of HD patients with cancer was similar to those without cancer （P=0.120）. Conclusion The urinary tract TCC is the most common cancer in HD patients with AAN in one of the centers of northern China.

Aristolochic Acid-Induced Genotoxicity and Toxicogenomic Changes in Rodents

Aristolochic acid(AA)is a group of structurally related nitrophenanthrene carboxylic acids found in many plants that are widely used by many cultures as traditional herbal medicines.AA is a causative agent for Chinese herbs nephropathy,a term replaced later by AA nephropathy.Evidence indicates that AA is nephrotoxic,genotoxic,and carcinogenic in humans;and it also induces tumors in the forestomach,kidney,renal pelvis,urinary bladder,and lung of rats and mice.Therefore,plants containing AA have been classified as carcinogenic to humans(Group 1)bytheInternational AgencyforResearchonCancer.In our laboratories,we have conducted a series of genotoxicity and toxicogenomic studies in the rats exposed to AA of 0.1–10 mg/kg for 12 weeks.Our results demonstrated that AA treatments induced DNA adducts and mutations in the kidney,liver,and spleen of rats,as well as significant alteration of gene expression in both its target and nontarget tissues.AA treatments altered mutagenesis-or carcinogenesis-related microRNA expression in rat kidney and resulted in significant changes in protein expression profiling.We also applied benchmark dose(BMD)modeling to the 3-month AA-induced genotoxicity data.The obtained BMDL10(the lower 95%confidence interval of the BMD10 that is a 10%increase over the background level)for AA-induced mutations in the kidney of rats was about 7μg/kg body weight per day.This review constitutes an overview of our investigations on AA-induced genotoxicity and toxicogenomic changes including gene expression,microRNA expression,and proteomics;and presents updated information focused on AA-induced genotoxicity in rodents.

Recent progress in quantitative analysis of DNA adducts of nephrotoxin aristolochic acid

Aristolochic acid (AA), a mixture of structure-related nitrophenanthrene carboxylic acid derivatives derived from Aristolochia spp, is associated with nephrotoxin and carcinogen. AA-DNA adducts induced by reductive metabolic activation of AA were detected in tissues of animals and in patients exposed to AA. The DNA adducts were generally used as biomarkers in toxicological study of AA. In this short review, quantitative analysis of AA-DNA adducts in various in vitro and in vivo systems by using 32P-postlabelling assay, HPLC-UV, HPLC-radiation monitor, HPLC-FLD, HPLC-ESI/MS and UPLC-MS/MS methods is discussed. The distribution of AA-DNA adducts in various tissues is also summarized.

Schisandra chinensis Oil Attenuates Aristolochic Acid Ⅰ-Induced Nephrotoxicity in vivo and in vitro

Objective: To investigate the protective effects of Schisandra chinensis oil(SCEO) against aristolochic acid Ⅰ(AAⅠ)-induced nephrotoxicity in vivo and in vitro and elucidate the underlying mechanism.Methods: C57BL/6 mice were randomly divided into 5 groups according to a random number table, including control group, AAⅠ group, and AAⅠ+SCEO(0.25, 0.5 and 1 g/kg) groups(n=5 per group). Pretreatment with SCEO was done for 2 days by oral administration, while the control and AAⅠ groups were treated with sodium carboxymethyl cellulose. Mice of all groups except for the control group were injected intraperitoneally with AAⅠ(5 mg/kg) from day 3 until day 7. Histopathological examination and apoptosis of kidney tissue were observed by hematoxylin and eosin and TdT-mediated dUTP nick-end labeling(TUNEL) staining, respectively. The levels of serum alanine aminotransferase(ALT), aspartate aminotransferase(AST), blood urea nitrogen(BUN), and serum creatinine(SCr), as well as renal malondialdehyde(MDA), glutathione, r-glutamyl cysteingl+glycine(GSH), and superoxide dismutase(SOD) were analyzed using enzyme-linked immunosorbent assay(ELISA).Expressions of hepatic cytochrome P450 1A1(CYP1A1), CYP1A2, and nad(p)hquinonedehydrogenase1(NQO1) were analyzed using ELISA, quantitative real-time polymerase chain reaction(qPCR) and Western blot,respectively. In vitro, SCEO(40 μg/mL) was added 12 h before treatment with AAⅠ(40 μmol/mL for 48 h) in human renal proximal tubule cell line(HK-2), then apoptosis and reactive oxygen species(ROS) were analyzed by flow cytometry. Results: SCEO 0.5 and 1 g/kg ameliorated histopathological changes and TUNEL+ staining in the kidney tissues of mice with AAⅠ-induced nephrotoxicity, and reduced serum levels of ALT, AST, BUN and SCr(P<0.01 or P<0.05). SCEO 0.5 and 1 g/kg alleviated the ROS generation in kidney, containing MDA,GSH and SOD(P<0.01 or P<0.05). SCEO 1 g/kg increased the expressions of CYP1A1 and CYP1A2 and decreased NQO1 level in the liver tissues(P<0.01 or P<0.05). Besides, in vitro studies also demonstrated that SCEO 40 μg/mL inhibited apoptosis and ROS generation(P<0.05 or P<0.01). Conclusions: SCEO can alleviate AAⅠ-induced kidney damage both in vivo and in vitro. The protective mechanism may be closely related to the regulation of metabolic enzymes, thereby inhibiting apoptosis and ROS production.