Time series analysis and prediction model of percentage of influenza-like illness （ILI） cases in Shanghai / 上海预防医学

ObjectiveTo predict the incidence trend of influenza-like illness proportion （ILI%） in Shanghai using the seasonal autoregressive integrated moving average model （SARIMA）， and to provide an important reference for timely prevention and control measures. MethodsTime series analysis was performed on ILI% surveillance data of Shanghai Municipal Center for Disease Control and Prevention from the 15th week of 2015 to the 52nd week of 2019， and a prediction model was established. Seasonal autoregressive integrated moving average （SARIMA） model was established using data from the foregoing 212 weeks， and prediction effect of the model was evaluated using data from the latter 36 weeks. ResultsFrom the 15th week of 2015 to the 52nd week of 2019， the average ILI% in Shanghai was 1.494%， showing an obvious epidemic peak. SARIMA（1，0，0） （2，0，0） 52 was finally modeled. The residual of the model was white noise sequence， and the true values were all within the 95% confidence interval of the predicted values. ConclusionSARIMA（1，0，0） （2，0，0） 52 can be used for the medium term prediction of ILI% in Shanghai， and can play an early warning role for the epidemic and outbreak of influenza in Shanghai.

Discovery and distribution of and response to arbovirus in China over the past seven decades / 中国血吸虫病防治杂志

Arbovirus is a group of virus transmitted by blood-sucking arthropod bites, which infects both arthropods and vertebrates. More than 600 arboviruses have been characterized worldwide until now, including 65 highly pathogenic viruses, which pose a high threat to public health. The risk of arbovirus transmission is increasing due to climate change, international trade and urbanization. The review summarizes the discovery and distribution of emerging and reemerging arboviruses and novel arboviruses with potential pathogenic risks, and proposes responses to the arbovirus transmission risk, so as to provide insights into the research and management of arboviruses and arthropod-borne infectious diseases in China.

Resveratrol protects H9c2 cells against hypoxia-induced apoptosis through miR-30d-5p/SIRT1/NF-κB axis

Previous studies have demonstrated the cardioprotective role of resveratrol (Res). However, the underlyingmolecular mechanisms involved in the protective role of Res are still largely unknown. H9c2 cells weredistributed into five groups: normal condition (Control), DMSO, 20 mMRes (dissolved with DMSO), hypoxia(Hyp), and Res?Hyp. Cell apoptosis was evaluated using flow cytometry and protein analysis of cleavedcaspase 3 (cle-caspase 3). qRT-PCR assay was performed to measure the expression of microRNA-30d-5p(miR-30d-5p). MTT assay was performed to evaluate the cell proliferation. The relationship between miR-30d5p and silent information regulator 1 (SIRT1) was confirmed by luciferase reporter, RNA immunoprecipitation(RIP), and western blot assays. Western blot was performed to analyze NF-jB/p65 and I-jBa expressions. Ourdata showed that hypoxia enhanced apoptosis and NF-jB signaling pathway, which was alleviated by Restreatment. Hypoxia increased the expression of miR-30d-5p while decreased the SIRT1expression, which wasalso attenuated by Res treatment. Furthermore, miR-30d-5p depletion inhibited the proliferation, reducedapoptosis and decreased the expression of cle-caspase 3 in H9c2 cells with hypoxia treatment. Luciferasereporter, RIP, and western blot assays further confirmed that miR-30d-5p negatively regulated the expression ofSIRT1. Interestingly, the rescue-of-function experiments further indicated that knockdown of SIRT1 attenuatedthe effect of miR-30d-5p depletion on proliferation, apoptosis NF-jB signaling pathway inH9c2 cells withhypoxia treatment. In addition, the suppression of NF-jB signaling pathway increased cell viability whiledecreased cell apoptosis in hypoxia-mediatedH9c2 cells. Our data suggested Res mayprotectH9c2 cells againsthypoxia-induced apoptosis through miR-30d-5p/SIRT1/NF-jB axis

Research progress on long non-coding RNA (lncRNA) in osteoarthritis / 中国骨伤

Osteoarthritis(OA) is a common clinical disease. The incidence of OA increases significantly with age, and the quality of life of patients is seriously affected. In the pathogenesis of OA, cartilage degeneration is the main cause. There are many long non-coding RNA (lncRNA) specifically expressed in osteoarthritis, which is closely related to the occurrence and development of osteoarthritis. Based on the latest research from 2014 to 2019, this paper summarizes the differential expression of lncRNA in osteoarthritis, the mechanism of lncRNA regulating chondrocyte function, and the mechanism of lncRNA regulating cartilage matrix metabolism. The fact that the expression of lncRNA is altered at different stages of OA development indicates that lncRNA can be developed forlife. The biomarkers and therapeutic targets can provide reference for the prevention, treatment and research of osteoarthritis.

Comparison and theoretical modeling of capillary electrophoresis analysis for the interaction between caffeine and serum proteins / 药学学报

The method for analyzing the interaction between caffeine and human serum albumin (HSA) was established by capillary electrophoresis. Under physiological conditions, the interaction between ligand (caffeine)-receptor (HSA) was studied with frontier-analysis (FA) method, Hummel-Dreyer (HD) method and plug-plug kinetic (PPK) method. The interaction parameters of caffeine-HSA system were obtained using non-linear equation, Scatchard equation and Klotz equation. The results showed that FA, HD and PPK methods were suitable for caffeine-HSA system, among them, HD method was the best, and the Non-linear equation was the best theoretical model to caffeine-HSA system. Interaction parameter tests showed that caffeine-HSA interaction was a single site interaction and the binding stability was moderate. The mechanism of caffeine-HSA interaction has been elucidated, which can provide valuable information for further research of alkaloids.

Regulatory Mechanism of MicroRNA-145 in the Pathogenesis of Acute Aortic Dissection

PURPOSE: Previous studies have confirmed that microRNAs play important roles in the pathogenesis of acute aortic dissection (AAD). Here, we aimed to explore the role of miR-145 and its regulatory mechanism in the pathogenesis of AAD. MATERIALS AND METHODS: AAD tissue samples were harvested from patients with aortic dissection and normal donors. Rat aortic vascular smooth muscle cells (VSMCs) were transfected with miR-145 mimic/inhibitor or negative control mimic/inhibitor. Gene and protein expression was measured in human aortic dissection tissue specimens and VSMCs by qRT-PCR and Western blot. Luciferase reporter assay was applied to verify whether connective tissue growth factor (CTGF) was a direct target of miR-145 in VSMCs. Methyl thiazolyl tetrazolium assay was used to detect VSMC viability. RESULTS: miR-145 expression was downregulated in aortic dissection tissues and was associated with the survival of patients with AAD. Overexpression of miR-145 promoted VSMC proliferation and inhibited cell apoptosis. Moreover, CTGF, which was increased in aortic dissection tissues, was decreased by miR-145 mimic and increased by miR-145 inhibitor. Furthermore, CTGF was confirmed as a target of miR-145 and could reverse the promotion effect of miR-145 on the progression of AAD. CONCLUSION: miR-145 suppressed the progression of AAD by targeting CTGF, suggesting that a miR-145/CTGF axis may provide a potential therapeutic target for AAD.

Physical fitness of preschool children in Kunshan city / 中国学校卫生

Objective@#To investigate current status and associated factors of preschool children’s physical fitness, in order to provide scientific basis for improving preschool children’s physical fitness.@*Methods@#A total of 3 240 preschool children aged 3-6 years old in Kunshan city were selected through cluster sampling method. They were surveyed about physical fitness and influencing factors.@*Results@#The number of excellence of preschool children’s physical fitness was 269, and the rate was 8.30 percent. The excellence rates of preschool children’s physical fitness in girls, high grade, non-residency in Jiangsu Province were higher(10.87%, 10.96%, 14.88%), and the excellence rate of preschool children’s physical fitness in premature group was lower(4.31%)(P<0.05). Further unconditioned logistic regression analysis found that girls, middle and high grade and non-residency in Jiangsu Province were the protective factors for the excellence of preschool children’s physical fitness, OR values were 1.96, 1.94, 2.45 and 1.87, respectively; premature was a risk factor for the excellence of preschool children’s physical fitness, OR value was 0.47.@*Conclusion@#Preschool children in Kunshan have poor physical fitness, especially in boys, low grade and premature groups. Education department and health department should work together to improve the preschool children’s physical fitness.

Recombinant Crimean-Congo hemorrhagic fever virus with Nanoluciferase reporter and its potential application for rapid antiviral compounds screening / 中华实验和临床病毒学杂志

Objective@#To construct the recombinant Crimean-Congo hemorrhagic fever virus (CCHFV) which can express the secreted nanoluciferase (NanoLuc) and investigate its potential application for rapid antiviral compounds screening.@*Methods@#The ORF of NanoLuc and the mucin encoded by the M segment of CCHFV were merged, and the recombinant CCHFV (rCCHFV) was rescued through reverse genetic system. Then rCCHFV was used to evaluate the antiviral effect for ribavirin and Furin inhibitor in vitro.@*Results@#The rCCHFV_mucin_NLuc with NanoLuc reporter was obtained, and the relative light unit (RLU) which can reflect NanoLuc activity was positively correlated with median tissue culture infective dose (TCID50) in the infected cell supernatant (cor=0.998, P=0.001). When the concentration for the compounds was 10 μmol/L, there was no significant difference for the NanoLuc activity in the infected cell supernatant between Furin inhibitor and ribavirin (P > 0.1) from day 1 to 3 after treatment. But at day 4, the NanoLuc activity in Fruin inhibitor treated group was significantly higher than that of ribavirin treated group (P=0.001), and no significant difference was found between the Furin inhibitor and untreated group (P > 0.1).@*Conclusions@#The rCCHFV with NanoLuc reporter was recovered successfully and it could be used for the primary rapid screening of antiviral compounds in future.

Effect of immune cells induced and differentiated by umbilical cord blood mononuclearcells on immune function of patients with small cell lung cancer / 中国肿瘤生物治疗杂志

@#Objective: To evaluate the effect of immune cells induced and differentiated by umbilical cord blood mononuclear cells (UCMCs) on the immune function of patients with small cell lung cancer (SCLC). Methods: Ninety patients with SCLC, who were admitted to the Affiliated Hospitalof InnerMongolia Medical University from January 2012 to December 2015, were randomly divided into control group (45 patients, EP regimen), study group (45 patients, EP regimen+UCMC-induced and differentiated immune cells). The study group of patients received immune cell treatment 3-5 d after chemotherapy ([1-3]×1010cells/treatment), 30 d for a cycle. The changes in T cell subsets, IFN-γ, IL-2, IL-10 and TGF-β1 in peripheral blood of patients were observed by flow cytometry at pre-treatment and 12 weeks post-treatment. Life quality and adverse events of patients were evaluated. Results: The study group, 15 cases achieved CR, 25 cases of PR and 5 cases of SD. The percent of T cell subsets in the study group was significantly higher than that in the control group (P<0.01), and the time of return to normal level was obviously shorter (P<0.05). The serum level of inflammatory cytokine IFN-γ increased or exceeded the normal range in 80.9% patients, and IL-10 and TGF-β1 levels were significantly decreased as compared with pretreatment (P<0.05). The quality of life was obviously better than that of the control group (P<0.05). Conclusion: Immune cells induced and differentiated by UCMCs can promote the recovery of immune function of patients with SCLC.

Clinical observation of cataract extraction combined with intraocular lens implantation in the treatment of multifocal intraocular lens / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To study the clinical effect of implantation of multifocal intraocular lens ( lOL ) combined with cataract extraction and lOL in cataract patients. ●METHODS:A total of 86 cases ( 86 eyes ) of cataract patients admitted to our hospital from Feb. 2014 to Mar. 2015 were divided into two groups according to the order of admission, each of 43 cases. The 43 patients with cataract extraction combined with non spherical astigmatism correction type monofocal lOL implantation for the treatment as the control group, the other 43 patients with cataract extraction combined with aspheric toric multifocal lOL implantation were treated as the observation group. After 1y of follow- up, the visual acuity, astigmatism and the contrast sensitivity of the two groups were observed. ●RESULTS: There was no difference in visual acuity between two groups (P>0. 05). Postoperative observation group of uncorrected near visual acuity ( UCNVA ) was significantly better than the control group (P0. 05). There was no difference in astigmatism between the two groups before and after operation ( P> 0. 05 ). There was no difference in contrast sensitivity between two groups ( P>0. 05). The contrast sensitivity of the control group was better than that of the observation group (P0. 05). ● CONCLUSION: Astigmatism correction multifocal intraocular lens on corneal astigmatism after surgery has a good effect, the naked eye near visual effect is better, the rest of the visual acuity is stable, good visual quality, worthy of clinical application and promotion.

The role of adenosine deaminase in the electroacupuncture preconditioning induced rapid tolerance to focal cerebral ischemia / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe the electroacupuncture (EA) pretreatment at Baihui (GV20) on the concentration of adenosine deaminase (ADA) and adenosine, and to evaluate its effects on the neurologic function score and the infarction volume after middle cerebral artery occlusion (MCAO) ischemia/reperfusion (I/R), thus exploring its mechanisms for relieving the ischemia/reperfusion injury.</p><p><b>METHODS</b>Totally 54 male SD rats were randomly divided into 3 groups, the sham-EA group, the EA group, and the control group, 18 in each group. Rats in the control group were not intervened after anesthesia. Rats in the EA group were needled at Baihui (GV20) for 30 min. Rats in the sham-EA group received the same procedure as those performed in the EA group without electricity connected. The changes of adenosine and ADA contents were detected at 30, 60, and 120 min after EA respectively. The I/R model was established. Totally 48 male SD rats were randomly divided into 6 groups, i.e., the model group (Group A), the EA group (Group B), the EA +8-Cyclopentyl-1,3-dipropylxanthine (DPCPX) group (Group C), the EA + DMSO group (Group D), the Deoxycoformycin (Deo) group (Group E), and the normal saline group (Group F). Rats in Group B, C, and D received EA for 30 min before modeling. Rats in Group C and D were peritoneally injected with DPCPX (1 mg/kg) and DMSO (1 mL/kg) at 30 min before EA. The neurologic function score was evaluated and the infarct volumes were detected after 24-h reperfusion.</p><p><b>RESULTS</b>Compared with the sham-EA group, there was no statistical difference in the contents of the adenosine or ADA in the control group at each time point (P > 0.05). Compared with the control group at the same time point, the content of ADA significantly decreased at 60 min in the EA group [(315.0 +/- 22.9 U/L), P < 0.05], and restored to the normal level at 120 min after EA. The content of adenosine increased in the EA group at 120 min [(20.4 +/- 2.2) ng/microL, P < 0.05]. Compared with the model group, the neurologic function score decreased (P < 0.05) and the infarct volumes were obviously reduced (P < 0.01) in Group B, D and E. There was no statistical difference in the neurologic function score or the infarct volumes in other groups, when compared with the model group (P > 0.05)</p><p><b>CONCLUSION</b>EA at Baihui (GV20) showed protective effects on the cerebral I/R rats, which might be achieved through lowering the ADA concentration and elevating the adenosine content, and further activating adenosine A1 receptor.</p>

Rapid detections of OprD2 gene in Pseudomoas aeruginosa using loop-mediated isothermal amplification / 中华检验医学杂志

Objective To establish a rapid detection approach by visual interpretation directly for OprD2 resistance gene of Pseudomonas aeruginosa based on the Loop-mediated isothermal amplification (LAMP),and provide a quick and effective method for clinical monitoring of Pseudomonas aeruginosa strains.Methods Totally 47 strains of Pseudomonas aeruginosa collected from December 2011 to June 2012 in Southwest Hospital of microorganisms were prospectively studied.Four LAMP primers (two inner,two outer) were designed according to the six zones of the OprD2 gene of Pseudomonas aeruginosa.A positive reaction is indicated by the color change after adding an intercalating dye (hydroxy naphthol blue) to the reaction solution.This method was used to detect and analyze the distribution of OprD2 resistance gene in 47 strains of Pseudomonas aeruginosa and its coirelation with antibiotic resistance.Results The LAMP assays showed 100％ specificity for the OprD2 gene,and the sensitivity (with the lowest detection limits of 17.414 μg/L) was 10-fold higher than that of conventional PCR assays.The OprD2 gene was negative in 23 strains by both conventional PCR and LAMP.In OprD2 negative strains,the resistance rate of cefotaxime,levofloxacin,aztreonam,piperacillin,imipenem and meropenem was 100％ (23/23),57％ (13/23),48％ (11/23),48％ (11/23),48％ (11/23) and 43％ (10/23).Compared with the OprD2 positive strains,statistical analysis showed that the resistance rate of imipenem,levofloxacin and meropenem in OprD2 negative strains increased significantly (chisquare value is 9.155,4.846,4.037,P value was 0.002,0.028,0.045,and so there was significant difference).Conclusions The established LAMP approach in this study enables rapid,sensitive and specific detection of OprD2 gene in Pseudomonas aeruginosa by visual interpretation.Deficiency of OprD2 gene confers Pseudomonas aeruginosa a basal level of resistance to carbapenems especially to imipenem.The identification of OprD2 gene distribution in Pseudomonas aeruginosa is helpful to the selection of antimicrobial agents in the infection treatment.

Genetic Characteristics of 2009 Pandemic H1N1 Influenza A Viruses Isolated from Mainland China / 中国病毒学·英文版

A total of 100 HIN1 flu real-time-PCR positive throat swabs collected from fever patients in Zhejiang,Hubei and Guangdong between June and November 2009,were provided by local CDC laboratories.After MDCK cell culture,57 Influenza A Pandemic (H1N1) viruses were isolated and submitted for whole genome sequencing.A total of 39 HA sequences,52 NA sequences,36 PB2 sequences,31 PB1 sequences,40 PA sequences,48 NP sequences,51 MP sequences and 36 NS sequences were obtained,including 20 whole genome sequences.Sequence comparison revealed they shared a high degree of homology (96％～99％) with known epidemic strains (A/Califomia/04/2009(H1N1).Phylogenetic analysis showed that although the sequences were highly conserved,they clustered into a small number of groups with only a few distinct strains.Site analysis revealed three substitutions at loop 220 (221-228) of the HA receptor binding site in the 39 HA sequences:A/Hubei/86/2009 PKVRDQEG→PKVRDQEA,A/Zhejiang/08/2009 PKVRDQEG→PKVRDQER,A/Hubei/75/2009PKVRDQEG→PKVRDQGG,the A/Hubei/75/2009 was isolated from an acute case,while the other two were from patients with mild symptoms.Other key sites such as 119,274,292 and 294 amino acids of NA protein,627 of PB2 protein were conserved.Meanwhile,all the M2 protein sequences possessed the Ser32Asn mutation,suggesting that these viruses were resistant to adamantanes.Comparison of these sequences with other H1N1 viruses collected from the NCBI database provides insight into H1N1 transmission and circulation patterns.

Improving fatty acid composition and increasing triacylglycerol content in plants by gene engineering: a review / 生物工程学报

This article reviewed key genes that involved in fatty acid synthesis and triacylglycerol assembly pathway. The transcription factors which play important roles in seed development and oil content were also reviewed. We summarized the achievement in modifying fatty acid composition and increase oil content in plant by gene engineering using these genes.

SNP Detection Relative to HBV Infection by DNA Piezoelectric Biosensor / 中华医院感染学杂志

OBJECTIVE To establish a SNP detection method by DNA piezoelectric biosensor and detect a SNP relative to HBV infection. METHODS To establish a model experiment with synthesis DNA sequences as target and find the lowest sensitivity. After extraction of genome DNA from inpatient blood sample, the SNP sites located in ESR1 gene region in samples were detected by SNP detecting method established. RESULTS The frequency shift of target-A was 416.0?21.5Hz, the frequency shift of target-G was 9.4?5.0Hz. And it could be detected that the lowest sensitivity of target-A was 2?10-11 mol/L. The three genotypes of blood samples, TT, TC and CC, had different frequency shifts, 109.4?13.4Hz, 52.0?11.4Hz and 7.2?4.5Hz, respectively. CONCLUSIONS SNP in blood sample could be detected specifically and sensitively by DNA piezoelectric biosensor.

Piezoelectric Gene Biosensors for Detection of Pseudomonas aeruginosa Using Signal Amplification Method with Cationic Conjugated Polymers / 中华医院感染学杂志

OBJECTIVE To discuss the feasibility of signal amplification method with cationic conjugated polymers(liposome) applied during the detection of Pseudomonas aeruginosa using piezoelectric gene biosensors.(METHODS) Oligonucleotide probe for P.aeruginosa was immobilized on the surface of gene sensor array and(hybridized) by PCR production of P.aeruginosa.After hybridization,liposome was added.The frequency shifts were recorded and compared with those ones of the control groups.RESULTS The frequency shifts were(significantly) increasing when adding liposome and the compatible concentration of liposome was 0.8?g/?l.(CONCLUSIONS) Liposome signal amplification is proved to be an effective method to amplify the piezoelectric(signal).

Immobilization Method on Piezoelectric Quartz Crystal DNA Sensors Based on Monolayer SAM / 中华医院感染学杂志

OBJECTIVE To discuss a highly effective method to immobilize probe on the surfaces of piezoelectric DNA sensors.METHODS Pseudomonas aeruginosa probe was immobilized on the gold surface of gene sensor(array) with routine self-assembly method(SAM)(non-reduction method) and SAM with deoxidized probe((reduction) method),respectively.The changes in frequency and time-cost were compared in reactions with(different) concentrations of probe.RESULTS Reduction method had the advantage of more probe immobilization;less time consumed in testing and higher changes in frequency during the reaction than non-reduction method.CONCLUSIONS Reduction method has a better ability to immobilize probe on the surfaces of piezoelectric DNA sensors.

Identification of Clostridium perfringens Causing Human Disease by Multiplex PCR / 中华医院感染学杂志

OBJECTIVE To search a method for identifying Clostridium perfringens and genotyping their toxin for gene diagnosis by multiplex PCR.METHODS The mutiplex PCR was developed with three sets of primers(designed) based on the sequences of three C.perfringens toxin genes(CP?,CP? and CPE) published in GenBank to identify C.perfringens and genotype their three toxin genes.RESULTS Three expected(sequences) were (obtained) successfully by multiplex PCR and identified by electrophoresis.CONCLUSIONS The(specific) sequences of C.perfringens could be amplified and their three genes of toxins could be identified by this multiplex PCR(system).Such method should be helpful for developing gene diagnosis well.

DNA Staining Efficiencies of Different Fluorescent Dyes in Preparative Agarose Gel Electrophoresis:A Comparative Analysis / 中华医院感染学杂志

OBJECTIVE To set-up safe alternatives to ethidium bromide(EB).METHODS Comparative analysis was performed on the DNA staining efficiencies of 4 fluorescent dyes including SYBR Gold,SYBR Green Ⅰ,(GoldView) and EB in preparative agarose gel electrophoresis.RESULTS Although both SYBR Gold and SYBR Green Ⅰ altered electrophoretic mobility and thus DNA size estimates,they were cost-effective alternatives to EB.SYBR Gold was more sensitive than SYBR Green Ⅰ at detecting short fragments,but 50 bp bands were clearly(visible) using either dye when visualized with a long integration time.CONCLUSIONS SYBR Gold or SYBR Green Ⅰ are sensitive and relatively safe alternatives to EB.

Expression and action of vascular endothelial growth factor and its receptor in a rat model of retinopathy of prematurity / 中华儿科杂志

<p><b>OBJECTIVE</b>To explore the expression of vascular endothelial growth factor (VEGF) and its receptors (flt-1 and flk-1) in the retina of retinopathy of prematurity (ROP), and its relation to the alteration of retinal blood vessels.</p><p><b>METHODS</b>Eighty-six newborn Sprague-Dawley rats were randomly divided into hyperoxia and air groups, then each group was further divided into 1, 3, 7 and 14 days subgroups. The rats in hyperoxia group inhaled 75% oxygen and ROP model was thus set up. These animals were sacrificed respectively after 1, 3, 7 and 14 days, then the retinal endothelial cells were marked by CD34 to observe the change of retinal blood vessels. The expression of VEGF, flt-1 and flk-1 in the retina was measured by immunohistochemistry.</p><p><b>RESULTS</b>The retinal capillary density index (RCDI) in control group increased as days went on (F = 21.589, P < 0.01, but it was the least on the 7th day in hyperoxia group, after the rats had been returned to air for 7 days, RCDI increased significantly (F = 67.885, P < 0.01); In the control group, the expression of VEGF and flk-1 was the strongest in the retina on the 7th day, the result had significant difference as compared with the 1st and 14th day (P < 0.05). The expression of VEGF and flk-1 on the 7th day in hyperoxia group was weaker than that of control group (P < 0.05). But on the 14th day in hyperoxia group, they were stronger than that of control (P < 0.05). The localization of the expression of flt-1 was changed when blood vessels altered, but there was no significant difference in expression intensity as a whole (P > 0.05).</p><p><b>CONCLUSION</b>When the premature retina was exposed to hyperoxia, the expression of VEGF and flk-1 was reduced, and retinal blood vessels were also decreased; but the expression of VEGF and flk-1 was stronger in retina when premature rats were exposed to relative hypoxia, and the retinal blood vessels also increased significantly. It is concluded that VEGF and flk-1 may play important roles in the development of retinal blood vessels and its change in ROP. However, flt-1 has less effect compared with flk-1.</p>