Background Sphingosine-l-phospate (S1P) is a bioactive lipid and important messenger molecule in cells.It participates in the regulation of many biological processes,such as cell proliferation,migration,survival,differentiation,apoptosis,etc.Hypoxia is a trigger factor of choriod neovascularization (CNV) and pathological basis of many diseases,and retinal pigment epithelial (RPE) cells are involved in formation of CNV.However,the effects of S1P on proliferation and apoptosis of RPE cells are below understood.Objective This study was to investigate the influence of S1P on proliferation and apoptosis of human RPE cells under hypoxic conditions.Methods Human RPE cells line-D407 cells were cultured and passaged and generation 3-5 cells were used and divided into 6 groups.The cells were regularly cultured in the blank control group using DMEM containing 10％ fetal bovine serum.CoCl2(200.00 μmol/L) was added into the colture medium for 2 hours in the hypooxic group.S1P of different concentrations (0.01,0.10,1.00,10.00 μmol/L) were added in culture medium 2 hours after the affection of 200.00 μmol/L CoCl2.The proliferative values of the cells were detected using WST-1 method as the absorbance (A value) and the proliferative rate of different groups were calculated.The apoptosis of the cells was assayed by Hoechst staining.The results were compared among different groups.Results Cultured cells showed the round-like in shape with clear nuclei and pigment.The proliferative values (A value) was 0.91 ±0.08,0.37±0.09,0.46±0.08,0.52±0.09,0.61 ±0.06,0.70±0.10 in the blank control group,hypoxic group and 0.01,0.10,1.00,10.00 μmol/L S1P groups,respectively,with a significant difference among the groups (F=21.104,P=0.000),and A values in various S1P groups were higher than those in the hypoxiac group (all at P＜0.05).The proliferative rate was gradually raised with the increase of dose of S1P.Hoechst staining exhibited a few apoptosis cells in the blank control group,but in the hypoxic group,a lots of apoptosis cells were seen with the light-blue nuclei and condensable chromatin.However,the number of apoptosis cells was significantly decreased in various concentrations of S 1 P groups.The apoptosis rates were (1.21 ±0.08) ％,(8.99 ±0.09) ％,(6.60 ±0.08) ％,(5.95 ±0.09) ％,(4.81 ± 0.06)％ and (3.96±0.10)％ in the blank control group,hypoxic group and the 0.01,0.10,1.00,10.00 μmol/L S1P groups,respectively,with a significant difference among the groups (F =25.070,P =0.000).Compared with the hypoxia group,the cellular apoptosis rates of various S1P groups were lower (all at P＜0.05).Conclusions Under the hypoxia condition,S1P can promote the proliferation of human RPE cells and inhibit apoptosis.

Background Several types of cells participate in the formation of proliferative membrane in proliferative retinopathy (PVR),and the proliferation,migration and epithelial-mesenchymal transition (EMT) of retinal pigment epithelium (RPE) cells play an important role.Many studies have confirmed high blood glucose is the basic pathogenesis of diabetic retinopathy (DR).However,whether EMT could be induced in RPE cells under the high glucose condition has not been reported.Objective This study was to investigate the effects of high glucose on the migration and EMT of RPE cells in high glucose culture model in vitro.Methods Human RPE cell line D407 were cultured and passaged in DMEM/F12 medium with 10％ fetal bovine serum,and 6-8 generations of cells were used in experiment.The cells were divided into 3 groups based on different glucose concentrations in medium.The glucose at the final concentration 5.5 mmol/L or 60.0 mmol/L was respectively used in the normal control group or high glucose group,and the DMEM with 5.5 mmol/L glucose and mannitol was used in the hypertonic control group.The migration rate of the cells were detected 0,24,48 and 72 hours after scratching by wound-scratch test.Real-time PCR was used to detect the relative expressions of zonula occludens-1 (ZO-1) and α-smooth muscle actin (α-SMA) in the cells.Results Cultured cells showed a polygon shape with the clear nucleolus and dense arrangement in the normal control group and the hypertonic control group,but the cells were larger and elongated with the lapse of culture time with the indistinct structure and loose arrangement.At 48 hours after scratching,migrating cells were seen in the scratching area,and the scratching area disappeared at 72 hours after scratching in the high glucose group,but the scratching area still was existed in the normal control group or hypertonic control group.The migrating rate of the cells was higher in the high glucose group than that in the normal control group or hypertonic control group,showing total differences among 3 groups and various time points (Fgroup =328.600,P =0.000 ; Ftime =773.270,P=0.000).Compared with the normal control group,the expression level of ZO-1 mRNA was significantly lower,and α-SMA mRNA level was higher 48 hours and 72 hours in the high glucose group than those in the normal control group (all at P＜0.05).Conclusions High glucose induce the migration and EMT of RPE cells in vitro,which may be associated with the pathogenesis of proliferative diabetic retinopathy.

Objective To examine the expression of stromal cell-derived factor-1 (SDF-1) in a rat model of retinal ischemia-reperfusion injury (RIRI),and investigate the protective effect of 17β-Estradiol (E2) on RIRI and explore the mechanism.Methods The RIRI model was established in Sprague-Dawley rats by increasing the intraocular pressure.Relative expression levels of SDF-1 mRNA and protein in the retina at 6 hours,12 hours and 24 hours following reperfusion was determined by RT-PCR and Western blot,respectively.E2 was administered to investigate the effects of estrogen on SDF-1 expression,and the estrogen receptor antagonist ICI 182-780 was administered to investigate the effect of estrogen receptor on the expression of SDF-1.Results SDF-1 expression in RIRI 6 hours group,12 hours group and 24 hours group was increased compared with normal control group (all P ＜ 0.05),with maximum expression at RIRI 12 hours group.As expected,pretreatment of RIRI rats with E2 had a protection on RIRI retina;SDF-1 expression was increased in RIRI + E2 group compared with IR control group and RIRI + vehicle group (all P ＜ 0.05).RIRI + E2 + ICI 182-780 group could decrease SDF-1 expression compared with RIRI + E2 group(all P ＜ 0.05).Conclusion E2 offers protection against RIRI by inducing an up-regulation in SDF-1 expression through activation of the estrogen receptor.

We wished to undertake molecular genetic typing and evaluate recombinants of the hepatitis-B virus (HBV) in Tibet (China). Multistage random sampling was used to collect HBsAg-positive samples. Nested polymerase chain reactions were used to amplify the whole sequence of the HBV. DNAstar, MEGA6 and SimPlot were used to assemble sequences, create phylogenetic trees, and undertake recombination analyses. Twelve whole sequences of the HBV of a Tibetan population were collected using these methods. Results showed that all 12 strains were C/D recombinants. Nine of the recombinations were at nt750, and the other three at nt1526. Therefore, the 12 strains could be divided into two types of recombinants: C/Da and C/Db. Analyses of the sequence of the whole genome revealed that the 12 strains belonged to genotype C, and that the nucleotide distance was > 4% between the 12 strains and sub-genotypes C1 to C15 in Genbank. The most likely sub-genotype was C1. Individuals with C/Da were from central and northern Tibet (e.g., Lasa, Linzhi, Ali) and those with C/Db recombinants were from Shannan in southern Tibet. These data suggest that the two types of recombinants had a good distribution in Tibet. Also, they can provide important information for studies on HBV recombination, gene features, virus evolution, as well as the control and prevention of HBV infection in Tibet.
Adult ; Female ; Genotype ; Hepatitis B ; virology ; Hepatitis B virus ; classification ; genetics ; isolation & purification ; Humans ; Male ; Phylogeny ; Recombination, Genetic ; Sequence Analysis, DNA ; Tibet ; Young Adult

Objective:To compare the four nucleic acid detection method of hepatitis A virus.Methods:Using method A, B, and C real-time fluorescent quantitative RT-PCR(RT-qPCR)and method D droplet chip digital PCR(RT-dPCR)to detect the sensitivity of HAV plasmid and gradient dilution HAV vaccine respectively. Specific detection of related viral nucleic acid was performed. Methods A, B, and C were used to detect 40 artificially contaminated HAV oysters, commercially available oysters and serum samples, and HAV vaccine samples, and compare the detection rates. The recovery rates of method A and D on artificially contaminated oysters were compared with low concentration of HAV.Results:Both method A and B could detect HAV plasmids up to 10 copies/μL. In the detection of HAV vaccine with gradient dilution, the slope, R 2 value and amplification efficiency of method A, B, and C were all within the acceptable range (-3.446~-3.297, 0.991-0.998, -95.07%-101.051%). For 40 specimens from different sources, the positive detection rates of method A, B, and C were 50% (20/40), 47.5% (19/40), 55% (22/40), and the difference was not statistically significant ( χ2=0.467, P=0.792). Methods A and D have no significant difference in the detection sensitivity of gradient dilution vaccines. For the detection of artificially contaminated oysters with low concentration of HAV, the recovery rate of method D was higher than that of method A, but the difference was not statistically significant (F=0.294, P=0.642). Conclusions:There is no significant difference between method A, B, and C, which is more convenient and fast. When detecting low concentrations of HAV in food, Methods D had a slight advantage, but the detection cost is slightly higher. The detection method can be selected according to the actual situation.

Objective:To optimize and compare method for hepatitis E virus (HEV) nucleic acid detection from pig liver, and provide technical references for HEV detection in animal viscera specimens.Methods:Three methods (PBS homogenization treatment, proteinase K treatment, chloroform extraction method) were used to pretreat and extract viral nucleic acid form pig liver, which was artificially contaminated with HEV fecal suspensions, and HEV RT-qPCR was used to compare the HEV recovery rate and inhibition rate. The optimized HEV method was applied to commercially available pig liver specimens, and HEV genotyping was performed on positive specimens.Results:The HEV recovery rate of PBS homogenization treatment, proteinase K treatment and chloroform extraction method was 9.88%, 0.19% and 17.28%, respectively. The recovery rate of proteinase K treatment was less than 1%, and it was discarded; t-test was performed to compare recovery rates of the other two methods, which showed statistically significant differences ( t=26.801, P<0.001), the chloroform extraction method had a higher recovery rate. The inhibition rates of the three methods were all less than 75%, within the range of the ISO/TS 15216-2∶2019 standard. Among 192 commercially available pig liver specimens, 17 specimens were detected positive for HEV RNA, with a nucleic acid positive rate of 8.85%; five specimens were successfully genotyped for HEV, all of which were genotype 4. Conclusions:The virus recovery effect was good when chloroform extraction method was used for pig liver pretreatment; moreover, this method could detect HEV RNA from commercially available pig livers, which indicate that it can be used for virus detection in food.

Objective To compare the performance of three nucleic acid detection methods for hepatitis E virus.Methods The open reading frame (ORF) 2 gene sequence of HEV genotype 4 representative strain was cloned into pUC57 vector.Plasmid DNA was detected by two real-time quantitative method A and B,and the detection limits were compared.Other samples were used for specificity detection.Serum specimens of acute hepatitis E patients were detected by three method,and the results were compared.Results The lowest detection limit of plasmid DNA by A and B method can both reach 35 copies/reaction,with specificity of 100％.The HEV RNA positive rate of serum samples from acute hepatitis E patients by A,B and C method was 47.8％ (43/90),43.3％ (39/90) and 41.1％ (37/90),with the concordance rate of 88.9％ (80/90).There was no statistically significant difference among the three method (x2=0.8414,P=0.6566).Serum specimens with Ct values below 34.6 detected by method A,or below 35.6 detected by method B,the success rate of amplification by method C was 100％.Conclusions Method A has both higher sensitivity and specificity,and method C is a sensitive gene detection method.

Objective:To compare the diagnostic performance of four IgM antibody diagnostic kits for hepatitis E virus (HEV) in an outbreak.Methods:Four reagent kits were used to detect the IgM antibody to HEV in serum samples of the subjects in an outbreak of hepatitis E, and the HEV RNA was detected; statistical analysis was carried out.Results:The detection rates of HEV IgM antibody with MP, Kehua, Wantai and Beier′s reagent kits were 40.00% (108/270), 29.26% (79/270), 28.52% (77/270) and 20.37% (55 /270), respectively, with a consistency rate of 78.52% (212/270). For HEV RNA positive samples, the sensitivity of MP, Kehua and Wantai’s reagents was 66.67% (32/48) and that of Beier’s reagent was 58.33% (28/48). The sensitivity of MP, Kehua and Wantai’s reagents was 69.81% (37/53) and that of Beier’s reagent was 60.38% (32/53) for sera from patients with acute hepatitis E. The detection rates of HEV IgM antibody in serum samples of RNA positive or acute hepatitis E clinical diagnosis cases of Beier-Kehua and Beier-Wantai were significantly different (McNemar’s test: P<0.05), but there was no significant difference between the detection rates of other reagents (McNemar’s test: P>0.05); for serum samples of HEV RNA negative or clinically excluded cases of acute hepatitis E, the detection rates of HEV IgM antibody of Kehua and Wantai’s reagents were the most similar (McNemar’s test: P>0.05), but the detection result of other reagents were significantly different (McNemar’s test: P<0.05). Conclusions:The diagnostic kits of MP, Kehua and Wantai for HEV IgM antibody have high sensitivity and are suitable for the early serological screening of acute hepatitis E. In the outbreak of hepatitis E, comprehensive diagnosis should be made by combining the detection result of HEV IgM antibody and HEV RNA.

Objective:The two detection method for the detection of hepatitis A virus (HAV) in strawberries were optimized and compared to select the best detection method for the detection of hepatitis A virus in strawberries.Methods:Different concentrations of HAV were inoculated on the surface of known negative frozen strawberry specimens, the concentration of beef extract powder in alkaline elution-PEG concentration method was optimized, the optimal nucleic acid extraction kit was selected, the optimal lysis buffer volume in direct lysis method was optimized, and the recovered viral load was detected by Real-time fluorescence quantitative RT-PCR. SPSS26.0 was used to statistically analyze the data, and the optimized two method were used for the detection of actual specimens.Results:The concentration of beef extract powder by the optimized alkaline elution-PEG concentration method was selected at 3%, and the viral nucleic acid extraction kit was selected as kit B. Six ml of lysis buffer was selected for the optimized direct lysis method. The recovery rates of HAV virus by alkaline elution-PEG concentration and direct lysis were compared with the HAV addition levels, and the HAV virus recovery rates of the two method were 21.50±1.06% and 5.82±0.01%, respectively, and the result showed that the differences were statistically significant. A total of 60 strawberry specimens from four regions were tested at the same time, and the result were all negative.Conclusions:The optimized alkaline elution-PEG concentration method has higher sensitivity and is more suitable for the detection of HAV in strawberry specimens.

Objective:To establish a digital droplet RT-PCR(dRT-PCR) method for Hepatitis A virus (HAV), and compare it with Real time RT-PCR(RT-qPCR) method, and select the best method for detecting hepatitis A virus in strawberry.Methods:Extract HAV vaccine RNA, optimize the reaction conditions of dRT-PCR and evaluate its specificity; Alkaline elution -PEG concentration method was used to extract nucleic acid from strawberry samples. At the same time, dRT-PCR and RT-qPCR method were used to detect the sensitivity and inhibition rate of HAV vaccine RNA in pure water and strawberry matrix, and the recovery rate of HAV in artificially contaminated strawberry was compared, which was applied to the detection of commercially available samples.Results:The optimal annealing temperature for dRT-PCR reaction was 60 ℃, and the optimal concentrations of primers and probes were 0.4 μmol/L、0.4 μmol/L and 0.2 μmol/L, with good specificity. There is no significant difference in sensitivity between the two method in detecting HAV vaccine RNA in pure water and strawberry matrix. The inhibition rate of dRT-PCR is low. The recovery rates of dRT-PCR and RT-qRCR in the detection of strawberry samples contaminated with HAV at higher concentrations were 12.90±0.006% and 30.12±0.02%, respectively. The recovery rates of lower concentrations of HAV contaminated strawberry samples were 18.27±0.07% and 10.85±0.03%, respectively, and the difference was statistically significant ( P<0.05). When strawberry samples on the market were tested, the result of both method were negative. Conclusions:The sensitivity of dRT-PCR method established in this study is not significantly different from that of RT-qPCR in detecting HAV RNA in different substrates, but dRT-PCR has good tolerance to PCR reaction inhibitors and high recovery rate when detecting low concentration HAV. Both detection method can be used for quantitative detection of hepatitis A virus in strawberry, and can be selected according to the actual situation.