Highly flexible yet strain-insensitive conjugated polymer.

Imparting excellent electrical properties, mechanical robustness, suppleness, conduction stability during deformation, and self-healing to intrinsic conducting polymers is a challenging endeavor. The reversibly interlocked macromolecular networks (RILNs) approach is utilized to tackle this problem. Specifically, poly(3,4-ethylenedioxythiophene) (PEDOT) is mixed with flexible polysulfonic acid networks crosslinked by reversible Diels-Alder bonds, while rigid polyaniline networks crosslinked by reversible Schiff base bonds act as molecular staples. Owing to the joint actions of the doping effect of polyaniline on PEDOT, the specific interlocking architecture and synergy between the component materials, the electrical conductivity (59.3-980.5 S cm-1), tensile strength (8.4-81.6 MPa) and elongation at break (44.5-411.0%) of the resultant PEDOT/RILNs films is significantly tunable according to different usage scenarios by adjusting the PEDOT content from 1.48 to 22.24 wt%. More importantly, the electrical resistance of PEDOT/RILNs remains constant during not only a single large extension and deflection but also repeated stretching (up to 1500 cycles) and bending (up to 106 cycles). The built-in reversible covalent bonds enable the PEDOT/RILNs to autonomously restore damaged mechanical and electrical performance. These record-breaking results and the demonstration of self-powered sensor made of PEDOT/RILNs suggest that the proposed approach successfully satisfies various conflicting requirements of flexible electronics regarding the properties of conducting polymers.

Efficacy of radiofrequency ablation combined with sorafenib for treating liver cancer complicated with portal hypertension and prognostic factors.

BACKGROUND: Patients with liver cancer complicated by portal hypertension present complex challenges in treatment. AIM: To evaluate the efficacy of radiofrequency ablation in combination with sorafenib for improving liver function and its impact on the prognosis of patients with this condition. METHODS: Data from 100 patients with liver cancer complicated with portal hypertension from May 2014 to March 2019 were analyzed and divided into a study group (n = 50) and a control group (n = 50) according to the treatment regimen. The research group received radiofrequency ablation (RFA) in combination with sorafenib, and the control group only received RFA. The short-term efficacy of both the research and control groups was observed. Liver function and portal hypertension were compared before and after treatment. Alpha-fetoprotein (AFP), glypican-3 (GPC-3), and AFP-L3 levels were compared between the two groups prior to and after treatment. The occurrence of adverse reactions in both groups was observed. The 3-year survival rate was compared between the two groups. Basic data were compared between the survival and non-surviving groups. To identify the independent risk factors for poor prognosis in patients with liver cancer complicated by portal hypertension, multivariate logistic regression analysis was employed. RESULTS: When comparing the two groups, the research group's total effective rate (82.00%) was significantly greater than that of the control group (56.00%; P < 0.05). Following treatment, alanine aminotransferase and aspartate aminotransferase levels increased, and portal vein pressure decreased in both groups. The degree of improvement for every index was substantially greater in the research group than in the control group (P < 0.05). Following treatment, the AFP, GPC-3, and AFP-L3 levels in both groups decreased, with the research group having significantly lower levels than the control group (P < 0.05). The incidence of diarrhea, rash, nausea and vomiting, and fatigue in the research group was significantly greater than that in the control group (P < 0.05). The 1-, 2-, and 3-year survival rates of the research group (94.00%, 84.00%, and 72.00%, respectively) were significantly greater than those of the control group (80.00%, 64.00%, and 40.00%, respectively; P < 0.05). Significant differences were observed between the survival group and the non-surviving group in terms of Child-Pugh grade, history of hepatitis, number of tumors, tumor size, use of sorafenib, stage of liver cancer, histological differentiation, history of splenectomy and other basic data (P < 0.05). Logistic regression analysis demonstrated that high Child-Pugh grade, tumor size (6-10 cm), history of hepatitis, no use of sorafenib, liver cancer stage IIIC, and previous splenectomy were independent risk factors for poor prognosis in patients with liver cancer complicated with portal hypertension (P < 0.05). CONCLUSION: Patients suffering from liver cancer complicated by portal hypertension benefit from the combination of RFA and sorafenib therapy because it effectively restores liver function and increases survival rates. The prognosis of patients suffering from liver cancer complicated by portal hypertension is strongly associated with factors such as high Child-Pugh grade, tumor size (6-10 cm), history of hepatitis, lack of sorafenib use, liver cancer at stage IIIC, and prior splenectomy.

Effects of different patterns of movement for correcting a deep curve of Spee with clear aligners on the anterior teeth: a finite element analysis.

OBJECTIVE: To analyse the anterior teeth effects of clear aligners on five different patterns of mandibular molar movement and to define the most effective configuration to be implemented with clear aligners through finite element analysis. METHODS: A three-dimensional mandibular model with a deep overbite in the mandible was constructed using cone beam computerized tomography (CBCT) data. The model included the mandibular dentition, mandibular periodontal ligaments, attachments, and aligners. Five models were created: (1) configuration A: second molar distalization (0.25 mm); (2) configuration B: second molar distalization (0.25 mm), first molar extrusion (0.15 mm); (3) configuration C: second molar distalization (0.25 mmm), first and second premolar extrusion(0.15 mm); (4) configuration D: second molar distalization (0.25 mm), first molar and first/second premolar extrusion(0.15 mm); and (5) configuration E: second molar distalization (0.25 mm), first molar and first/second premolar extrusion (0.15 mm), first molar and first/second premolar expansion (0.15 mm). RESULTS: In all configurations, the anterior teeth exhibited labial tipping and the mandibular central incisor of configuration E showed the highest labial tipping. Configuration E demonstrated a relatively minor impact on mandibular molars distalization compared with configuration A. Configuration A showed the highest distal displacement value, and configuration E produced the lowest displacement value. Configuration E caused the highest periodontal ligament (PDL) pressure of the central and lateral incisors. The differences in the canines between configurations C and D,were not significant, and the stress distribution differed among the five groups. CONCLUSIONS: All patterns utilizing clear aligners facilitated mandibular molar distalization. Extruding the premolars and second molar distalization at the same time had little impact on second molar distalization; When expansion and extrusion were simultaneously performed during the distalization of mandibular molars, our prime consideration was the alveolar bone on the labial side of the anterior teeth to prevent the occurrence of gingival recession, dehiscence, and fenestration. Due to the lack of consideration for periodontal tissues in this study, clinical protocols should be designed based on the periodontal status of the mandibular anterior teeth.

Hydrothermally Derived Green Carbon Dots from Broccoli Water Extracts: Decreased Toxicity, Enhanced Free-Radical Scavenging, and Anti-Inflammatory Performance.

Biomass carbon dots (CDs) derived from natural plants possess the advantages of low cost, photostability, and excellent biocompatibility, with potential applications in chemical sensing, bioimaging, and nanomedicine. However, the development of biomass CDs with excellent antioxidant activity and good biocompatibility is still a challenge. Herein, we propose a hypothesis for enhancing the antioxidant capacity of biomass CDs based on precursor optimization, extraction solvent, and other conditions with broccoli as the biomass. Compared to broccoli water extracts, broccoli powders, and broccoli organic solvent extracts, CDs derived from broccoli water extracts (BWE-CDs) have outstanding antioxidant properties due to the abundant C═C, carbonyl, and amino groups on their surface. After optimization of the preparation condition, the obtained BWE-CDs exhibit excellent free-radical scavenging activity with an EC50 of 68.2 µg/mL for DPPH• and 22.4 µg/mL for ABTS•+. Cytotoxicity and zebrafish embryotoxicity results indicated that BWE-CDs have lower cytotoxicity and better biocompatibility than that of CDs derived from organic solvents. In addition, BWE-CDs effectively scavenged reactive oxygen species (ROS) in A549 cells, 293T cells, and zebrafish, as well as eliminating inflammation in LPS-stimulated zebrafish. Mechanistic studies showed that the anti-inflammatory effect of BWE-CDs was dependent on the direct reaction of CDs with free radicals, the regulation of NO levels, and the upregulation of the expression of SOD and GPX-4. This work indicates that the antioxidant activity of CDs could be enhanced by using solvent extracts of biomass as precursors, and the obtained BWE-CDs exhibit characteristics of greenness, low toxicity, and excellent antioxidant and anti-inflammatory activities, which suggests the potential promising application of BWE-CDs as an antioxidant nanomedicine for inflammatory therapy.

Extraction of weak hydrophobic sulforaphane from broccoli by salting-out assisted hydrophobic deep eutectic solvent extraction.

In order to extract sulforaphane (SFN) from broccoli via green and efficient ways, a novel method based on salting-out assisted deep eutectic solvent (DES) has been developed. Compared to known organic solvent- (such as dichloromethane, ethyl acetate, n-hexane, etc.) based liquid-liquid extraction, this new N8881Cl-based DES method exhibited excellent extraction efficiency for SFN, including a significant improvement due to the salting-out effect of KH2PO4. Under optimal conditions, 97.77 % of SFN was extracted by N8881Cl-EG DES and more than 82.5 % of SFN was recovered by activated carbon from DES. In addition, further studies with Kamlet-Taft parameters and density functional theory showed that the H-bond accepting capacity of hydrophobic DES, the existing vdW interaction, and the electrostatic interaction between N8881Cl-EG DES all contributed to efficient extraction of SFN. This is the first time that the underlying mechanism for SFN extraction by DES was revealed.

One-pot method based on deep eutectic solvent for extraction and conversion of polydatin to resveratrol from Polygonum cuspidatum.

The acquisition of resveratrol from Polygonum cuspidatum is complicated and costs organic solvents due to extraction and hydrolysis of its corresponding glycoside (polydatin). In this work, a novel one-pot method based on deep eutectic solvent (DES) was developed for simultaneous extraction and conversion of polydatin to resveratrol from Polygonum cuspidatum for the first time. The extraction yield of resveratrol by DES-based one-pot method were significantly higher than that of water, methanol and ethanol. After optimization by One-Variable-at-a-Time and response surface methodology, the extraction yield of resveratrol reached 12.26 ± 0.14 mg/g within 80 min. The conversation efficiency of polydatin to resveratrol in Polygonum cuspidatum from five different origins was more than 96.3%. Scanning electron microscope results indicated the selected DES disrupted plant cell walls to enhance the yield of resveratrol. The results indicated that one green method was successfully established for efficient extraction and conversion of polydatin to resveratrol from Polygonum cuspidatum.

[Whole genome sequencing reveals the distribution of resistance and virulence genes of pathogenic Escherichia coli CCHTP from giant panda].

Pathogenic Escherichia coli (E. coli) is the most common pathogen causing urinary tract infection in animals. We investigated the antibiotic resistance and virulence genes of pathogenic E. coli CCHTP derived from urine with occult blood of the giant panda by whole genome sequencing. The flanking sequencing of resistance and virulence genes in genomic islands were also analyzed. Our results demonstrate that E. coli CCHTP contains different families of antibiotic resistance genes, most of which are efflux pump related genes, including multiple drug resistance efflux pump genes mdfA, emrE, and mdtN. A total of 166 virulence factors and 563 virulence genes were identified, and the most virulence factors and related genes are involved in host cell attachment and invasion processes. Furthermore, sequence analysis of 19 genomic islands revealed that antibiotic and virulence genes are associated with mobile genetic elements (transposon and insertion sequence) in GIs011 and GIs017. These structures can mediate horizontal transfer of antibiotic and virulence genes. Our work described the distribution of antibiotic resistance genes and virulence genes in E. coli CCHTP, which may provide an important guidance for treatment and rational drug use of E. coli CCHTP infection in the giant panda.

[Evolution and the flanking sequences of Β-lactamase resistance gene blaOKP].

blaOKP genes are chromosomally encoded beta-lactamases that mediate several classes of antibiotics resistance. To investigate the evolution and flanking sequences of OKP beta-lactamase gene, the gene blaOKP and its flanking sequences from a newly isolated Klebsiella pneumoniae were studied using whole genome sequencing. The flanking sequences of different variant blaOKP genes and blaSHV, another plasmid-encoded beta-lactamase gene, were then compared. These studies show that the blaOKP and blaSHV genes evolve differently and belong to two different evolution branches. The blaOKP gene variants can be divided into subgroups: blaOKP-A and blaOKP-B. Although both blaOKP and blaSHV genes have no mobile genetic elements in their flanking sequences, their genetic environments are quite different. The blaOKP gene is adjacent to KdpC while blaSHV gene is flanked by RecF and ygbN-ygbM-ygbK. Furthermore, there are a variety of mobile genetic elements in the neighboring sequence plasmid-encoded blaSHV genes that are absent in blaOKP genes. These structural differences may slow the evolution of blaOKP gene. Collectively, we demonstrate that the evolution and flanking sequence of blaOKP gene are different from those of the blaSHV gene, which could be an important reason for its relatively slow evolution.

Antibiotic and disinfectant resistance of Salmonella isolated from egg production chains.

To investigate the contamination of Salmonella and its drug resistance in egg production chains, 111 Salmonella strains of different serotypes isolated from egg production chains were used in the study. The minimum inhibitory concentrations (MICs) of antibiotics and disinfectants against Salmonella isolates were determined, meanwhile, antibiotic and disinfectant resistance genes were amplified. The results showed that the resistance frequency of trimethoprim (TMP, N=100, P=90.09%) was highest among Salmonella isolates and all isolates were sensitive to amoxicillin and clavulanate (AMC), ceftiofur sodium (CFS) and gentamicin (CN), respectively. There were six different antibiotic resistance profiles, and TMP profile was the most prevalent type (N=36, P=32.43%). 52.25% of Salmonella isolates appeared multi-drug resistance. The MICs of benzalkonium chloride (BC) and cetylpyridinium chloride (CPC) against Salmonella strains ranged from 8 to 128 µg/mL and 8 to 256 µg/mL, respectively. Compared to quality control strain Escherichia coli ATCC10536, 101 Salmonella isolates (P=90.99%) had dual resistances to BC and CPC. 109 Salmonella (P=98.20%) were co-resistant to antibiotic and disinfectant. Detection of drug resistance genes showed that blaTEM gene was dominant (N=49, P=44.14%). The qnrA, qnrB and qepA genes were not detected. Only qacEΔ1 gene (N=63, P=56.76%) was detected among the disinfectant resistance genes. There was a significant correlation between sul1 gene and qacEΔ1 gene (P < 0.01). S. Derby showed multi-resistances to TMP, oxytetracycline (OTC), amoxicillin (AML) and ciprofloxacin (CIP). Eleven antibiotic resistance genes were found in S. Derby, in which the prevalence of qacEΔ1 gene was 81.25% (N=52). Besides, the drug resistance frequency and the prevalence of drug resistance genes in internal farm environment were higher than those in external environment. High frequency of drug resistances and high prevalence of drug resistance genes were detected in all links of the egg production chains, including package, storage and sale. Our results showed that severe antibiotic and disinfectant resistances existed in egg production chains. Therefore, further hygiene supervision should be implemented to prevent and control Salmonella, and standardize the use of antibiotics and disinfectants.

Oral delivery of capsaicin using MPEG-PCL nanoparticles.

AIM: To prepare a biodegradable polymeric carrier for oral delivery of a water-insoluble drug capsaicin (CAP) and evaluate its quality. METHODS: CAP-loaded methoxy poly (ethylene glycol)-poly(ε-caprolactone) nanoparticles (CAP/NPs) were prepared using a modified emulsification solvent diffusion technique. The quality of CAP/NPs were evaluated using transmission electron microscopy, powder X-ray diffraction, differential scanning calorimetry and Fourier transform infrared techniques. A dialysis method was used to analyze the in vitro release profile of CAP from the CAP/NPs. Adult male rats were orally administered CAP/NPs (35 mg/kg), and the plasma concentrations of CAP were measured with a validated HPLC method. The morphology of rat gastric mucosa was studied with HE staining. RESULTS: CAP/NPs had an average diameter of 82.54 ± 0.51 nm, high drug-loading capacity of 14.0% ± 0.13% and high stability. CAP/NPs showed a biphasic release profile in vitro: the burst release was less than 25% of the loaded drug within 12 h followed by a more sustained release for 60 h. The pharmacokinetics study showed that the mean maximum plasma concentration was observed 4 h after oral administered of CAP/NPs, and approximately 90 ng/mL of CAP was detected in serum after 36 h. The area under the curve for the CAP/NPs group was approximately 6-fold higher than that for raw CAP suspension. Histological studies showed that CAP/NPs markedly reduced CAP-caused gastric mucosa irritation. CONCLUSION: CAP/NPs significantly enhance the bioavailability of CAP and markedly reduce gastric mucosa irritation in rats.

[Construction and expression of the eukaryotic expression vector containing AIF gene].

OBJECTIVE: To construct the eukaryotic express vector containing apoptosis-inducing factor (AIF) gene and to study its expression in A549 cells. METHODS: According to the GenBank AIF mRNA sequence, specific primers to amplify AIF gene from lung carcinoma cell line A549 by RT-PCR was designed. The amplified AIF gene fragment was cloned into plasmid pUC-T by TA cloning, then double enzyme digestion and DNA sequencing were used to identifying the positive recombinant AIF-pUC-T. The target fragment was retrieved and cloned into the eukaryotic express vector pcDNA3.1(+). The positive recombinant AIF-pcDNA3.1(+) was transfected into A549 cells, and expression of AIF gene was verified by RT-PCR and Western blot. RESULTS: AIF target gene was successfully amplified and cloned into the pUC-T. The target fragment was retrieved and cloned into the eukaryotic express vector pcDNA3.1(+), and it was completely coincided with the AIF sequence in GenBank suggested by cells transfected with AIF-pcDNA3. 1(+) was much higher than that of control cells which was not transfected with AIF-pcDNA3.1(+). CONCLUSION: The AIF eukaryotic expression vector AIF-pcDNA3.1(+) is successfully constructed in A549 cells and it could be experimental foundations for further study of AIF gene.

In vitro release and in vitro-in vivo correlation for silybin meglumine incorporated into hollow-type mesoporous silica nanoparticles.

BACKGROUND: The purpose of this study was to develop a sustained drug-release model for water-soluble drugs using silica nanoparticles. METHODS: Hollow-type mesoporous silica nanoparticles (HMSNs) were prepared using Na(2)CO(3) solution as the dissolution medium for the first time. The water-soluble compound, silybin meglumine, was used as the model drug. The Wagner-Nelson method was used to calculate the in vivo absorption fraction. RESULTS: The results of transmission electron microscopy and nitrogen adsorption revealed that the empty HMSNs had uniformly distributed particles of size 50-100 nm, a spherical appearance, a large specific surface area (385.89 ± 1.12 m(2)/g), and ultralow mean pore size (2.74 nm). The highly porous structure allowed a large drug-loading rate (58.91% ± 0.39%). In 0.08 M Na(2)CO(3) solution, silybin meglumine-loaded HMSNs could achieve highly efficacious and long-term sustained release for 72 hours in vitro. The results of in vitro-in vivo correlation revealed that HMSNs in 0.08 M Na(2)CO(3) solution had a correlation coefficient R(2) value of 0.9931, while those of artificial gastric juice and artificial intestinal juice were only 0.9287 and 0.7689, respectively. CONCLUSION: The findings of in vitro-in vivo correlation indicate that HMSNs together with Na(2)CO(3) solution could achieve an excellent linear relationship between in vitro dissolution and in vivo absorption for 72 hours, leading to a promising model for sustained release of water-soluble drugs.

Delivery of a transforming growth factor ß-1 plasmid to mesenchymal stem cells via cationized Pleurotus eryngii polysaccharide nanoparticles.

The objective of this study was to investigate the use of cationized Pleurotus eryngii polysaccharide (CPEPS) as a nonviral gene delivery vehicle to transfer plasmid DNA encoding transforming growth factor beta-1 (pTGF-ß1) into mesenchymal stem cells (MSCs) in vitro. Crude P. eryngii polysaccharide was purified, and then cationized by grafting spermine onto the backbone of the polysaccharide. Agarose gel electrophoresis, transmission electron microscopy, and a Nano Sense Zetasizer (Malvern Instruments, Malvern, UK) were used to characterize the CPEPS-pTGF-ß1 nanoparticles. The findings of cytotoxicity analysis showed that when the nanoparticles were formulated with a CPEPS/pTGF-ß1 weight ratio ≥ 10:1, a greater gel retardation effect was observed during agarose gel electrophoresis. The CPEPS-pTGF-ß1 nanoparticles with a weight ratio of 20:1, respectively, possessed an average particle size of 80.8 nm in diameter and a zeta potential of +17.4 ± 0.1 mV. Significantly, these CPEPS-pTGF-ß1 nanoparticles showed lower cytotoxicity and higher transfection efficiency than both polyethylenimine (25 kDa) (P = 0.006, Student's t-test) and Lipofectamine(TM) 2000 (P = 0.002, Student's t-test). Additionally, the messenger RNA expression level of TGF-ß1 in MSCs transfected with CPEPS-pTGF-ß1 nanoparticles was significantly higher than that of free plasmid DNA-transfected MSCs and slightly elevated compared with that of Lipofectamine 2000-transfected MSCs. Flow cytometry analysis demonstrated that 92.38% of MSCs were arrested in the G1 phase after being transfected with CPEPS-pTGF-ß1 nanoparticles, indicating a tendency toward differentiation. In summary, the findings of this study suggest that the CPEPS-pTGF-ß1 nanoparticles prepared in this work exhibited excellent transfection efficiency and low toxicity. Therefore, they could be developed into a promising nonviral vector for gene delivery in vitro.

Efficient gene delivery to mesenchymal stem cells by an ethylenediamine-modified polysaccharide from mulberry leaves.

This study investigates the use of a natural polysaccharide isolated from mulberry leaves as a nonviral gene vector. Ethylenediamine is chemically grafted to the backbone of a polysaccharide from mulberry leaves (MPS) to acquire nucleic acid binding affinity. A particle-size observation indicates that the cationic mulberry leaf polysaccharide (CMPS) can efficiently combine with plasmid transforming growth factor ß1 (TGF-ß1) to form nanoscaled particles. In addition, the electrophoresis assay indicates a retarded plasmid migration when the CMPS/pTGF-ß1 weight ratio is increased to 30:1. The in vitro cell transfection experiment is performed based on bone marrow mesenchymal stem cells (MSCs) derived from rat femurs and tibias, and the findings reveal that the complex with a CMPS/pTGF-ß1 weight ratio of 50:1 exhibits the highest cell transfection effect, which is significantly higher than that of branched poly(ethyleneimine) (PEI) (25 kDa; p = 0.001, Student's t-test) and slightly higher than Lipofectamine 2000. Moreover, the cytotoxicity assay also demonstrates that all of these tested complexes and the plasmid TGF-ß1 are nontoxic to mesenchymal stem cells (MSCs). The results of the living cell imaging confirm that more of the CMPS/plasmid TGF-ß1 nanoparticles can be taken up and at a faster rate by the MSCs than by the positive control Lipofectamine 2000; these data are consistent with the transfection efficiency data. Together, these results suggest that the CMPS/pTGF-ß1 nanoparticle can potentially be developed into a promising alternative for the transfer of therapeutic genes into cells.

[Effect of DNA polymerase beta on apoptosis and mitochondrial membrane potential induced by hydroquinone, a metabolite of benzene].

OBJECTIVE: To explore the effect and mechanism of DNA polymerase ß expression level on cell apoptosis and mitochondrial membrane potential induced by hydroquinone. METHODS: Polß wild-type cells (polß+/+), polß overexpressed cells (polß oe) and polß null cells (polß-/-) were applied as a model cell system, The effect of cell apoptosis and mitochondrial membrane potential induced by different doses of hydroquinone were analyzed by flow cytometry. The ROS and ·OH assay kit were used to examine the cellular ROS and ·OH level. The activity of cellular SOD and GSH-Px were tested by Chemiluminescence method after exposed to different concentrations of hydroquinone. RESULTS: With the dose of hydroquinone increased, the rate of apoptosis and falling of mitochondrial membrane potential (ΔΨm) in cells were increased compared with the control. When compared with polß+/+ cells, the rate of apoptosis in polß-/- cells exposed to 20.00, 40.00, 80.00 µmol/L hydroquinone increased and the rate of apoptosis in polß oe cells exposed to 10.00, 20.00, 40.00, 80.00 µmol/L hydroquinone decreased (P < 0.05). Compared with polß+/+ cells (20.60% ± 0.57%, 37.95% ± 0.64%, 44.50% ± 1.27%, 57.55% ± 1.06%), the rate of cell which undergone mitochondrial depolarization in polß-/- cells treated with 10.00, 20.00, 40.00, 80.00 µmol/L hydroquinone (33.60% ± 1.55%, 46.05% ± 1.77%, 52.75% ± 2.05%, 75.20% ± 0.56%) increased. The rate of cell which undergone mitochondrial depolarization in polß oe cells exposed to 10.00, 20.00, 40.00, 80.00 µmol/L hydroquinone (16.05% ± 1.20%, 29.80% ± 1.21%, 35.15% ± 1.06%, 53.80% ± 0.85%) decreased (P < 0.05). When compared with polß+/+ cells, fluorescent intensity of polß-/- cells treated with different dosages of hydroquinone increased, while which of polß oe cells decreased (P < 0.05). Compared with polß+/+ cells, ·OH level of polß-/- cells treated with 20.00, 40.00 µmol/L hydroquinone significantly enhanced, while which of polß oe cells decreased sharply (P < 0.05). Under the same concentrations of hydroquinone, the activity of SOD and GSH-Px were decreased most rapidly in polß-/- cells. The activity of SOD and GSH-Px in polß oe cells decreased slower than in the polß-/- cells. CONCLUSION: Hydroquinone could induced apoptosis by the generation of ROS and decrease of ΔΨm; polß could protect cells from apoptosis induced by hydroquinone through decrease of ROS level and depolarization of mitochondria.