Objective:To observe the effects of SARS-CoV-2 infection on the morphology, proliferation, apoptosis, cell cycle, and immune response function of mouse retinal photoreceptor cells (661w cells).Methods:A cell experiment. Logarithmic growth phase 661w cells were cultured in vitro and transfected with angiotensin-converting enzyme 2 (ACE2) overexpressing lentivirus to construct ACE2 overexpressing 661w cells that could be infected with SARS-CoV-2 pseudovirus (hereafter referred to as 'pseudovirus’). The 661w cells were divided into three groups: the normal group (untreated), the siACE2 group (overexpressing ACE2 and not infected with the pseudovirus) and the infected group (overexpressing ACE2 and infected with the pseudovirus), in which the infected group was 5 TU/ml pseudovirus group, 15 TU/ml pseudovirus group, 30 TU/ml pseudovirus group and 50 TU/ml pseudovirus group, and the cells were infected with the pseudovirus for 12, 24, 48 and 72 h, respectively. The infected group was infected with 5 TU/ml pseudovirus group, 15 TU/ml pseudovirus group, 30 TU/ml pseudovirus group and 50 TU/ml pseudovirus group, respectively, for 12, 24, 48 and 72 h. Fluorescence microscopy was used to observe the transfection efficiency of ACE2; protein immunoblotting (Western blot) was used to detect the relative expression level of ACE2 in the cells; light microscope was used to observe the morphology of the cells in the normal and the infected groups; cell proliferation was detected by Cell Counting Kit-8 (CCK8) assay; flow cytometry was used to detect the cell cycle; Western blot and real-time quantitative polymerase chain reaction (qPCR) were used to detect the relative expression of interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), B lymphocytoma-2 (Bcl-2), Bcl-2-associated X-protein (Bax) proteins and mRNA in the cells of siACE2 group, infected group (30 TU/ml pseudovirus group); qPCR was used to detect the relative expression of nuclear factor ( NF)- κB1 and NF-κB2, as well as NF- kB enhancer ( P65) and precursor protein ( P100) in cells of the siACE2 group and the infected group (30 TU/ml pseudovirus group). One-way ANOVA was used for comparison between multiple groups; t-test was used for comparison between two groups. Results:Compared with the siACE2 group, the cells in the infected group showed different degrees of crumpling, and with the increase of the concentration and time of pseudovirus induction, the crumpling of the cells worsened, and the number of cells decreased. Compared with the normal group, the cells in the infected group showed a gradual decrease in cell viability with the prolongation of pseudovirus induction time, and the difference was no statistically significant ( F=0.840, 0.412, 1.498, 1.138; P>0.05), and the apoptotic index of the cells induced in the 30 and 50 TU/ml pseudovirus group was significantly elevated, and the difference was statistically significant ( F=2.523, 6.716, 3.477, 3.421; P<0.05). At 72 h of pseudovirus induction, compared with the siACE2 group, the G1 phase cells in the 30 TU/ml pseudovirus group were significantly increased, and the difference was statistically significant ( t=3.812, P<0.05); the relative expression of IL-6, TNF-α, Bax protein and mRNA in the cells was up-regulated ( t=7.601, 6.039, 3.088, 5.193, 6.427, 7.667; P<0.05), the relative expression of Bcl-2 protein and mRNA was down-regulated ( t=3.614, 6.777; P<0.05), and the relative expression of NF-κB1, NF-κB2, P65, and P100 mRNA was significantly up-regulated with statistically significant differences ( t=3.550, 3.074, 3.307, 4.218; P<0.05). Conclusion:SARS-CoV-2 infection may inhibit photoreceptor cell proliferation, promote apoptosis and cycle blockade by activating the NF-κB signalling pathway.

Objective To investigate whether vascular endothelial cells in choroidal neovascularization whether hypoxia condition can up-regulate SNAI1 and activate matrix metalloproteinase (MMP)2 and MMP9 therefore to participate in choroidal neovascularization(CNV).Methods Sixteen SPF male C57 mice aged 6-8 weeks were divided into control group and model group.CNV models were induced by retinal laser photocoagulation,and flatmount and frozen sections of retinal pigment epithelium (RPE)-choroid-sclera compound were prepared at 7 days after modeling.The CNV in flat-mount was examined by Isolectin B4 staining,and the location of SNAI1,MMP2 and MMP9 in frozen sections was determined by immunofluorescence technology.The expression of SNAI1,MMP2 and MMP9 at mRNA level in CNV was detected by real-time fluorescence quantitative PCR (real-time PCR).The use and care of experimental animals complied with Statement for the Use of Animals in Ophthalmic and Visual Research.The RF/6A cells were divided into normoxia group and hypoxia group and cultured for 24 hours in 5％ CO2condition and mix condition of 94％ N2,5％ CO2 and 1％ O2,respectively.The expression of SNAI1,MMP2 and MMP9 in the cells at mRNA and protein levels was detected by real-time PCR and Western blot assay,respectively.Small interfering RNA of SNAI1 (siSNAI1) was transfected into the cells,and then the expression of MMP2 in the cells at mRNA and protein levels was detected by real-time PCR and Western blot assay,respectively,and the migrating number of the cells was assayed by Transwell chamber assay.Results CD31 and SNAI1 positive-response cells were seen in RPE-choroid-sclera flat-mounts under the laser scanning confocal microscope.The relative expression levels of SNAI1mRNA and MMP2 mRNA in RPE-choroid-sclera tissues were higher in the model group than those in the control group (SNAI1 mRNA:1.291 ±0.060 vs.0.759±0.074,P =0.001;MMP2 mRNA:1.610±0.424 vs.0.772 ±0.080,P =0.044).The expression of MMP9 mRNA was not significantly elevated between model group and control group (P＞0.05).The relative expression level of MMP2 mRNA was higher in comparison with MMP9 mRNA in the model group (P＜0.01).The relative expressions of hypoxic induced factor 1α (HIF-1α),SNAI1 and MMP2 at mRNA level and protein level in RF/6A cells were significantly higher in the hypoxia group than those in the normoxia group (all at P＜0.05) and no considerable difference was seen in MMP9 mRNA expression between the two groups (P＞0.05).The relative expressions of MMP2 mRNA in the cells were 0.217±0.036 and 0.818±0.105,and those of MMP2 protein in the cells were 0.236±0.009 and 1.043±0.120 in the hypoxia+siSNAI1 group and only hypoxia group,respectively,with significant differences between them (P =0.002,0.003).The migrating number of the cells was (254.60 ±71.31)/field in the hypoxia+siSNAI1 group,which was significantly less than (534.10±96.21) /field in the control group (P =0.029).Conclusions The hypoxic environment at CNV can activate MMP2 by up-regulating the expression of SNAI1,which promotes the migration of vascular endothelial cells and therefore participates in CNV formation,and the intervention of SNAI1 activation under the hypoxic condition can inhibit this process.

Objective:To investigate the molecular expression and pathological features of endothelial cell (EC) in a murine model of choroidal neovascularization (CNV) based on single-cell RNA sequencing (scRNA-seq).Methods:Six C57BL/6 mice aged 6-8 weeks were randomly divided into two groups, with 3 mice in each group.Bilateral eyeballs were enucleated.The choroidal tissues from the two groups were isolated by shearing the complex and scraping the choroid, respectively.Single-cell suspension was prepared by continuous digestion with trypsin/type Ⅰ collagenase at 37 ℃, and the cell viability and EC ratio were detected by flow cytometry to determine the preparation method of single-cell suspension.Another 6 mice were randomly assigned into the control group and the CNV group, with 3 mice in each group.The CNV model was induced by laser photocoagulation and single-cell suspensions were prepared 7 days after modeling.Gene expression library construction was performed using the Chromi-um (10x Genomics) instrument.High throughput sequencing was performed using the Illumina Novaseq6000 to obtain the expression matrix.The EC subpopulations were classified according to previous researches and the Cellmarker database.Pseudo-time analysis was performed in EC, revealing the gene expression matrix of different states.CNV-EC were further selected with preliminary analysis of the expression characteristics.Another 6 mice were selected to establish the CNV model and eyeball frozen sections were prepared 7 days after modeling.Expression and distribution as well as the area percentage of EC marker Pecam1, mitochondrial outer membrane proteins Tomm20 and mt-Co1, and capillary markers Kdr and Plvap were observed by immunofluorescence staining, and the vascular diameter was calculated.The use and care of animals followed the ARVO statement.This study protocol was approved by the Experimental Animal Welfare and Ethics Committee of Air Force Military Medical University (No.20200181).Results:The cell viability of the single-cell suspension prepared from choroidal-scleral fragments and choroidal scrapings was 99.4% and 99.1%, respectively, both of which met the sequencing requirements.The percentage of EC detected by flow cytometry was approximately 1.58%.The scRNA-seq result revealed that both the normal control and CNV groups contained 13 choroidal cell clusters.Compared with the normal control group, the proportions of rod/cone photoreceptor cells, EC and hematopoietic cells all increased, while the retinal pigment epithelium (RPE) and Schwan cells reduced in the CNV group.Among all clusters, EC constituted 18.4%.The pseudo-time analysis demonstrated that EC could be further divided into 4 states.The percentage of state 2 EC was 29.1% in the CNV group, which was significantly higher than 9.5% in the normal control group.Differentially expressed gene analysis showed that the expression of mitochondrion-related genes, including mt-Nd4 and mt-Atp6, were upregulated in state 2 EC, while capillary-related genes, including Kdr and Esm1, were downregulated.Immunofluorescent staining revealed that the area of Tomm20 and mt-Co1 in Pecam1-positive EC in the CNV area was (19.50±4.68)% and (4.64±2.82)%, respectively, which were both higher than (3.00±2.09)% and (0.18±0.34)% in normal area ( t=7.88, 3.84; both at P<0.01). The area of Kdr and Plvap in Pecam1-positive EC in the CNV area was (1.50±0.29)% and (0.79±0.97)%, respectively, which were both lower than (31.30±5.44)% and (10.43±2.28)% in the normal area ( t=13.40, 9.48; both at P<0.01). The vascular diameter in the CNV area was (5.52±1.85)μm, which was larger than (4.21±1.84)μm in the normal area ( t=9.57, P<0.001). Conclusions:When CNV occurs, the proportion of EC in choroid increases, and CNV-EC shows pathologic features of mitochondrial metabolic activation and loss of capillary properties, suggesting the mitochondrial activation of EC may play a role in the formation of CNV.

Objective To enrich the clinical meanings of common pulse manifestations,and to explore mechanisms of those pulses by analyzing the correlation between pattern elements of disease nature and common pulse manifestations in patients with viral hepatitis or cirrhosis based on the combination of pat-tern and diseases.Methods A national multicenter cross-sectional epidemiological survey was conduc-ted to collect TCM symptoms,tongue manifestations and pulse conditions(including depth,frequency, width,length,hardness,and frequency of pulse)of patients with viral hepatitis or cirrhosis.The survey questionnaire used the Information Collection form of Vital Hepatitis Cirrhosis drafted by the research group.Standard ofHepatitis Cirrhosis Pattern Elements Differentiation was made to identify patterns and pattern elements.Descriptive statistics such as frequency and rate,Chi-square test,and correlation analy-sis were used.Results Pulses of 801 patients were collected.Pulses with occurrence rate above 20％was defined as common pulse manifestations,in which wiry pulse accounted for 75.2％ (n =602);thready pulse,29.0 ％ (n =279);deep pulse 29％ (n =232);and slippery pulse,23.1％ (n =185). There was positive correlation between wiry pulse and blood stasis and qi stagnation (correlation coefficient was 0.141 and 0.166 respectively,P <0.05).There was positive correlation between slippery pulse and yin deficiency and damp heat (correlation coefficient were 0.093 and 0.131 respectively,P <0.05).There was positive correlation between deep pulse and qi deficiency and yang deficiency(correlation coefficient was 0.099 and 0.111 respectively,P <0.05).There was positive correlation between thready pulse pulse and yin deficiency,qi deficiency,yang deficiency and water retention(correlation coefficient was 0.089,0.109, 0.105 and 0.075 respectively,P <0.05).Conclusion There is a certain correlation between pattern ele-ments and common pulse manifestations in viral hepatitis cirrhosis patients.