Cloning, partial sequence, expression, and antigenic analysis of the filamentous hemagglutinin gene of Bordetella pertussis.

The gene coding for the filamentous hemagglutinin (FHA), one of the main factors involved in mediating adherence of Bordetella pertussis to ciliated host cells, was cloned in Escherichia coli, and the 3,500-base-pair nucleotide sequence encoding the amino-terminal region was determined. Molecular cloning, together with the characterization of recombinant FHA-related proteins produced in E. coli, revealed that the primary translation product is a protein of about 370 kilodaltons (kDa). The mature 220-kDa FHA polypeptide secreted by B. pertussis is most probably generated by proteolytic processing that eliminates a carboxy-terminal portion of about 150 kDa. The 1,087 amino-terminal residues of the predicted FHA sequence showed a number of remarkable features. Extensive homology to the Serratia marcescens and Proteus mirabilis hemolysin proteins was found between amino acids 91 and 205 of the FHA sequence, suggesting involvement of this FHA domain in host cell binding or secretion of FHA from B. pertussis. In addition, two regions containing repetitive amino acid sequences were identified. One region, extending from residues 382 to 664, was formed by six repeats, and a second, extending from residues 701 to 912, contained three repeats. The reactivities of several recombinant FHA-derived proteins with a panel of monoclonal antibodies identified at least four epitopes composing an immunoreactive domain present in the carboxy-terminal moiety of the mature FHA.     

Extracellular DNA-dependent biofilm formation by Staphylococcus epidermidis RP62A in response to subminimal inhibitory concentrations of antibiotics

We measured the ability of Staphylococcus epidermidis to form biofilms in the presence of subminimal inhibitory concentrations (sub-MICs) of vancomycin, tigecycline, linezolid and novobiocin. Six strains that produce different amounts of biofilm were tested. The three strains that produced the highest amounts of biofilm exhibited steady-state or decreased biofilm formation in the presence of sub-MIC antibiotics, whereas the three strains that produced lower amounts of biofilm exhibited up to 10-fold-increased biofilm formation in the presence of sub-MIC antibiotics. In two of the inducible strains (9142 and 456a), antibiotic-induced biofilm formation was inhibited by dispersin B, an enzyme that degrades poly-N-acetylglucosamine (PNAG) biofilm polysaccharide. In the third inducible strain (RP62A), dispersin B inhibited biofilm formation in response to sub-MIC vancomycin, but not to sub-MIC tigecycline. In contrast, DNase I efficiently inhibited biofilm formation by strain RP62A in response to sub-MIC tigecycline and vancomycin. DNase I had no effect on antibiotic-induced biofilm formation in strains 9142 and 456a. Our findings indicate that antibiotic-induced biofilm formation in S. epidermidis is both strain- and antibiotic-dependent and that S. epidermidis RP62A utilizes an extracellular DNA-dependent mechanism to form biofilms in response to sub-MIC antibiotics.     

Biofilm formation and cellulose expression by Bordetella avium 197N,the causative agent of bordetellosis in birds and an opportunistic respiratory pathogen in humans

Although bacterial cellulose synthase (bcs) operons are widespread within the Proteobacteria phylum, subunits required for the partial-acetylation of the polymer appear to be restricted to a few γ-group soil, plant-associated and phytopathogenic pseudomonads, including Pseudomonas fluorescens SBW25 and several Pseudomonas syringae pathovars. However, a bcs operon with acetylation subunits has also been annotated in the unrelated β-group respiratory pathogen, Bordetella avium 197N. Our comparison of subunit protein sequences and GC content analyses confirms the close similarity between the B. avium 197N and pseudomonad operons and suggests that, in both cases, the cellulose synthase and acetylation subunits were acquired as a single unit. Using static liquid microcosms, we can confirm that B. avium 197N expresses low levels of cellulose in air–liquid interface biofilms and that biofilm strength and attachment levels could be increased by elevating c-di-GMP levels like the pseudomonads, but cellulose was not required for biofilm formation itself. The finding that B. avium 197N is capable of producing cellulose from a highly-conserved, but relatively uncommon bcs operon raises the question of what functional role this modified polymer plays during the infection of the upper respiratory tract or survival between hosts, and what environmental signals control its production.     

Effects of estriol on growth,gene expression and estrogen response element activation in human breast cancer cell lines

Objective

Local application of estradiol (E2) to treat vulvovaginal atrophy in postmenopausal breast cancer patients receiving aromatase inhibitors is known to elevate serum estradiol levels and thereby might counteract breast cancer therapy. Thus, vaginal application of estriol (E3) has been recommended for these patients. However, it is unclear to what extent E3 stimulates breast cancer cell growth. In this study, we examined the effect of E3 on growth and gene expression of two human breast cancer cell lines.

Methods

We used an established in vitro cell culture assay and compared the effect of E2 and E3 on growth of the estrogen receptor alpha-positive breast cancer cell lines MCF-7 and T-47D testing a wide range of hormone concentrations of 10⁻¹²–10⁻⁷ M. E3 effects on gene expression were examined by means of reporter gene assays, RT-qPCR and Western blot analysis.

Results

E3 acted as a potent estrogen and exerted a mitogenic effect on T-47D and MCF-7 cells at concentrations of 10⁻⁹ M (288 pg/ml) and higher. With regard to activation of an estrogen response element (ERE) in breast cancer cells, effects of E3 were visible at 10⁻¹⁰ M. The same concentrations of E3 activated expression of the estrogen-responsive gene PR and of the proliferation genes cyclin A2, cyclin B1, Ki-67, c-myc and b-myb, providing molecular mechanisms underlying the observed growth increase.

Conclusions

Like E2, low levels of E3 were able to trigger a robust estrogenic response in breast cancer cells. Thus, our data suggest caution regarding use of E3 by breast cancer survivors.     

The use of quaternised chitosan-loaded PMMA to inhibit biofilm formation and downregulate the virulence-associated gene expression of antibiotic-resistant staphylococcus

Biomaterial-associated infections remain a serious complication in orthopaedic surgery. Treatments, including the local use of antibiotic-loaded polymethylmethacrylate (PMMA) bone cement, are not always successful because of multiantibiotic-resistant organisms. In this study, we synthesised a new quaternised chitosan derivative (hydroxypropyltrimethyl ammonium chloride chitosan, HACC) that contains a series of substitutions of quaternary ammonium and demonstrated that HACC with a 26% degree of substitution (DS; referred to as 26%HACC) had a strong antibacterial activity and simultaneously good biocompatibility with osteogenic cells. We loaded 26%HACC at 20% by weight into PMMA bone cement to investigate whether HACC in PMMA prevents bacterial biofilm formation on the surface of bone cements. Chitosan-loaded PMMA (at the same weight ratio), gentamicin-loaded PMMA and PMMA with no antibiotic were also investigated and compared. Two clinical isolates, Staphylococcus epidermidis 389 and methicillin-resistant S. epidermidis (MRSE287), and two standard strains, S. epidermidis (ATCC35984) and methicillin-resistant Staphylococcus aureus (ATCC43300), were selected to evaluate the bacterial biofilm formation at 6, 12 and 24 h using the spread plate method, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The results showed that 26%HACC-loaded PMMA inhibited biofilm formation on its surface, while the PMMA control and chitosan-loaded PMMA were unable to inhibit biofilm formation. The gentamicin-loaded PMMA decreased the number of viable methicillin-resistant Staphylococcus strains, but its ability to inhibit biofilm formation was lower than 26%HACC-loaded PMMA. Real-time PCR demonstrated that 26%HACC-loaded PMMA markedly downregulated the expression of icaAD, which encodes essential enzymes for polysaccharide intercellular adhesion (PIA) biosynthesis, upregulated the expression level of icaR, which negatively mediates icaAD expression, and also downregulated the expression of MecA, which encodes membrane-bound enzymes known to be penicillin-binding proteins. Our study indicates that 26%HACC-loaded PMMA prevents biofilm formation of Staphylococcus, including antibiotic-resistant strains, on the surface of bone cement, and downregulates the virulence-associated gene expression of antibiotic-resistant staphylococcus, thus providing a promising new strategy for combating implant infections and osteomyelitis.     

Microarray analysis of thyroid stimulating hormone, insulin-like growth factor-1, and insulin-induced gene expression in FRTL-5 thyroid cells

To determine which genes are regulated by thyroid stimulating hormone (thyrotropin, TSH), insulin and insulin-like growth factor-1 (IGF-1) in the rat thyroid, we used the microarray technology and observed the changes in gene expression. The expressions of genes for bone morphogenetic protein 6, the glucagon receptor, and cyclin D1 were increased by both TSH and IGF-1; for cytochrome P450, 2c37, the expression was decreased by both. Genes for cholecystokinin, glucuronidase, beta, demethyl-Q 7, and cytochrome c oxidase, subunit VIIIa, were up-regulated; the genes for ribosomal protein L37 and ribosomal protein L4 were down-regulated by TSH and insulin. However, there was no gene observed to be regulated by all three: TSH, IGF-1, and insulin molecules studied. These findings suggest that TSH, IGF-1, and insulin stimulate different signal pathways, which can interact with one another to regulate the proliferation of thyrocytes, and thereby provide additional influence on the process of cellular proliferation.     

病毒感染大鼠心室肌细胞钙通道基因表达及功能改变的研究

目的：研究大鼠心室肌细胞感染柯萨奇病毒B3（CVB3）后L型钙通道mRNA表达量及其电生理特性的变化。 方法: 用CVB3感染培养的SD大鼠心室肌细胞，采用半定量逆转录-聚合酶链式反应技术，检测病毒感染心室肌细胞L型钙通道各亚单位mRNA表达量的变化；用全细胞膜片钳技术，观察病毒感染前后心室肌细胞L型钙电流（ICa-L）的变化。结果: 病毒感染组心室肌细胞L型钙通道α1和β亚单位mRNA的表达量显著高于正常对照组（4.00±0.07 vs 2.21±0.41, P<0.01; 2.06±0.06 vs 1.22±0.30, P<0.05），而α2/δ亚单位mRNA表达量的改变不明显（4.12±0.19 vs 4.13±0.27, P>0.05）；感染组细胞ICa-L的平均电流密度明显大于正常组细胞［（-8.66±0.99) pA/pF vs (-6.97±1.75) pA/pF, P<0.01］，且前者的电流-电压曲线下移，峰电流密度增加25.74%（P<0.05）。结论: CVB3感染心室肌细胞后，使其L型钙通道α1和β亚单位mRNA的表达量增加，ICa-L增大，可能是病毒感染导致心肌出现异常电生理活动的细胞和分子机制之一。     

Identification and characterization of a conserved,stage-specific gene product of Plasmodium falciparum recognized by parasite growth inhibitory antibodies

We have identified a novel conserved protein of Plasmodium falciparum, designated D13, that is stage-specifically expressed in asexual blood stages of the parasite. The predicted open reading frame (ORF) D13 contains 863 amino acids with a calculated molecular mass of 99.7 kDa and displays a repeat region composed of pentapeptide motives. Northern blot analysis with lysates of synchronized blood stage parasites showed that D13 is highly expressed at the mRNA level during schizogony. The first N'-terminal 138 amino acids of D13 were expressed in Escherichia coli and the purified protein was used to generate anti-D13 monoclonal antibodies (MAbs). Using total lysates of blood stage parasites and Western blot analysis, these MAbs stained one single band of approximately 100 kDa, corresponding to the predicted molecular mass of ORF D13. Western blot analysis demonstrated further that D13 is expressed during schizogony, declines rapidly in early ring stages and is undetectable in trophozoites. D13 protein is localized in individual merozoites in a distinct area, as demonstrated by indirect immunofluorescence analysis. After subcellular fractionation, D13 was confined to the pelleted fraction of the parasite lysate and its extraction by alkaline carbonate buffer treatment indicated that D13 is not a membrane-integral protein. Inclusion of certain anti-D13 MAbs into in vitro cultures of blood stage parasites resulted in considerable reduction in parasite growth. The N'-terminal domain encompassing 158 amino acids is 94 and 95%, respectively, identical at the amino acid level between Plasmodium knowlesi, Plasmodium yoelii, and P. falciparum. In summary, we describe a novel stage-specifically expressed, highly conserved gene product of P. falciparum that is recognized by parasite growth inhibitory antibodies.     

Histamine hypersensitivity in mice induced by Bordetella pertussis or pharmacologic beta adrenergic blockade. Effects of adrenergic, cholinergic, and other drugs.

The effects of prostaglandin E1, E2, F2alpha (PGE2 PGF2alpha), isoproterenol, epinephrine, norepinephrine, salbutamol, practolol, atropine, aminophylline, and corticosterone on the hypersensitivity to anaphylaxis, histamine, and serotonin in Bordetella pertussis-treated mice and propranolol-treated mice were investigated. Female HLA-SW (ICR) mice, 27-29 gm, were injected with pertussis vaccine intravenously 4 days before challenge with antigen, histamine, or serotonin. Alternatively, instead of pertussis vaccine, propranolol was injected intraperitoneally 45 min before histamine challenge. Test drugs were administered intraperitoneally 15 min before challenge. PGE1 and PGE2 at a narrow range of between 10 and 100 mug and epinephrine at 100 mug protected both pertussis- and propranolol-treated mice. Isoproterenol (25 mug) and aminophilline (800 mug) protected beta-blocked mice, but did not protect pertussis-treated mice even with very high doses (1,000 and 3,2000 mug, respectively), although salbutamol (500 mug) did. PGF2alpha, norepinephrine, and atropine were not protective at all. Practolol, a beta 1-blocker, given intraperitoneally 30 min before histamine neither sensitized normal mice nor changed the effect of isoproterenol or salbutamol in pertussis-treated mice. Corticosterone 10 mg/kg reduced the number of deaths from histamine in beta-blocked mice, but not in pertussis-treated mice. The protective effect is discussed in connection with probable effects of the drugs on intracellular cyclic adenosine monophosphate (cAMP) levels.     

针刺康复疗法影响脑性瘫痪模型大鼠大脑病变组织生长相关蛋白43和突触小泡蛋白的表达

BACKGROUND:Acupuncture + rehabilitation therapy is the most effective treatment for cerebral palsy. Growth associated protein-43 and synaptophysin were characteristic markers for neurodevelopment and synaptic density, and involved in nerve cell growth, repair, regeneration and synapse remodeling. OBJECTIVE:To study the effects of acupuncture + rehabilitation therapy on the expression of growth associated protein-43 and synaptophysin in cerebral palsy rats and to investigate the mechanism of acupuncture + rehabilitation therapy on cerebral palsy.   METHODS:The 125 rats were randomly divided into five groups: sham group, model group, rehabilitation group, acupuncture group, and acupuncture + rehabilitation group. Rat models of cerebral palsy were established in model group, rehabilitation group, acupuncture group, and acupuncture + rehabilitation group. Rat models in the sham and model groups did not receive treatment. Rat models in the rehabilitation group underwent rehabilitation training. Rat models in the acupuncture group were subjected to acupuncture. Rat models in the acupuncture + rehabilitation group underwent rehabilitation training and acupuncture. RESULTS AND CONCLUSION:(1) Motor function: The motor function scores were better in the acupuncture + rehabilitation group than in the model, acupuncture, and rehabilitation groups (P < 0.05). (2) Growth associated protein-43 and synaptophysin expression: immunohistochemical staining revealed that compared with the model group, growth associated protein-43 expression at 2-4 weeks and synaptophysin expression at 4 and 5 weeks were higher in the acupuncture and acupuncture + rehabilitation groups (P < 0.05); the increase in above expression was most significant in the acupuncture + rehabilitation group (P < 0.05). (3) Results confirmed that acupuncture combined with rehabilitation promoted growth associated protein-43 and synaptophysin expression in rats with cerebral palsy and exerted neuroprotective effect.     

Determination of minimum inhibitory concentrations of itraconazole,terbinafine and ketoconazole against dermatophyte species by broth microdilution method

Purpose: Various antifungal agents both topical and systemic have been introduced into clinical practice for effectively treating dermatophytic conditions. Dermatophytosis is the infection of keratinised tissues caused by fungal species of genera Trichophyton, Epidermophyton and Microsporum, commonly known as dermatophytes affecting 20–25% of the world’s population. The present study aims at determining the susceptibility patterns of dermatophyte species recovered from superficial mycoses of human patients in Himachal Pradesh to antifungal agents; itraconazole, terbinafine and ketoconazole. The study also aims at determining the minimum inhibitory concentrations (MICs) of these agents following the recommended protocol of Clinical and Laboratory Standards Institute (CLSI) (M38-A2). Methodology: A total of 53 isolates of dermatophytes (T. mentagrophyte-34 in no., T. rubrum-18 and M. gypseum-1) recovered from the superficial mycoses were examined. Broth microdilution method M38-A2 approved protocol of CLSI (2008) for filamentous fungi was followed for determining the susceptibility of dermatophyte species. Results: T. mentagrophyte isolates were found more susceptible to both itraconazole and ketoconazole as compared to terbinafine (MIC₅₀: 0.125 μg/ml for itraconazole, 0.0625 μg/ml for ketoconazole and 0.5 μg/ml for terbinafine). Three isolates of T. mentagrophytes (VBS-5, VBSo-3 and VBSo-73) and one isolate of T. rubrum (VBPo-9) had higher MIC values of itraconazole (1 μg/ml). Similarly, the higher MIC values of ketoconazole were observed in case of only three isolates of T. mentagrophyte (VBSo-30 = 2 μg/ml; VBSo-44, VBM-2 = 1 μg/ml). The comparative analysis of the three antifungal drugs based on t-test revealed that ‘itraconazole and terbinafine’ and ‘terbinafine and ketoconazole’ were found independent based on the P < 0.005 in case of T. mentagrophyte isolates. In case of T. rubrum, the similarity existed between MIC values of ‘itraconazole and ketoconazole’ and ‘terbinafine and ketoconazole’. Conclusion: The MIC values observed in the present study based on standard protocol M38-A2 of CLSI 2008 might serve as reference for further studies covering large number of isolates from different geographic regions of the state. Such studies might reflect on the acquisition of drug resistance among isolates of dermatophyte species based on MIC values.     

Comparison of carbapenem minimum inhibitory concentrations of Oxacillin-48-like Klebsiella pneumoniae by Sensititre,Vitek 2, MicroScan,and Etest

ObjectivesThe aim of this laboratory-based study was to compare carbapenem MICs yielded by Sensititre, Vitek 2, MicroScan WalkAway plus and Etest for Oxacillin (OXA)-48-like Klebsiella pneumoniae isolates.MethodsAnalysis was performed for categorical agreement for ertapenem, meropenem, and imipenem, and the proportion of isolates with MICs ≤8μg/mL and the MIC50/MIC90 for meropenem and imipenem, from a convenience sample of 82 deduplicated blood culture OXA-48-like K. pneumoniae isolates.ResultsThe proportion of isolates testing susceptible to ertapenem by Etest (19/82, 23.1%) differed from Sensititre/Vitek (0/82) and MicroScan (2/82, 2.4%) (p < 0.001 for all). For meropenem, the proportion of isolates susceptible by Etest (31/82, 37.8%) differed from Sensititre/Vitek (16/82, 19.5%) (p = 0.015). There was variation in the proportion of isolates that tested imipenem susceptible when comparing Sensititre (9/82, 11%) and Vitek (8/82, 9.8%) to MicroScan (27/82, 32.9%), p = 0.001 and p < 0.001, respectively, Sensititre and Vitek to Etest (45/82, 54.9%), p < 0.001 for both, and MicroScan to Etest, p = 0.007. The proportion of isolates with meropenem MICs ≤8μg/mL with Sensititre and Vitek differed significantly from Etest, 58.5% and 85.4%, respectively, p < 0.001. A 2-fold difference between the Sensititre and Vitek meropenem and imipenem MIC at which ≥50% of isolates were inhibited compared to the MicroScan, and a 4-fold difference compared to Etest, was present.ConclusionsSubstantial variability in carbapenem MICs for OXA-48-like carbapenemase-producing Enterobacterales isolates by the four methods was demonstrated. Performance characteristics verification of MIC methods in use for the predominant carbapenemase-producing Enterobacterales type is required by laboratories to optimize the accuracy of carbapenem reporting.     

RNA阵列技术检测自发性高血压大鼠肌浆网Ca2+-ATP酶和受磷蛋白基因表达

目的:探讨肌浆网Ca²⁺-ATP酶(SERCA)和受磷蛋白(PLB)在原发性高血压发病过程中的变化特点及其相互关系。方法:提取2、4、6、8、10、12不同周龄雄性自发性高血压大鼠(SHR)和正常血压大鼠(WKY)的心室肌、血管平滑肌、肝脏和肾脏组织的总RNA,共294个样品,利用高通量RNA阵列技术(RNAarray)检测SERCA和PLB基因在不同周龄SHR和WKY中mRNA表达谱改变。结果:SHR在6、8、10、12周龄血压出现显著高于同周龄WKY(均P<0.01),10、12周龄心室肌重量／体重比出现显著增加(均P<0.01),心肌和血管平滑肌SERCA的表达在4、6、8、10、12周龄出现显著高于同周龄WKY(P<0.05或P<0.01)。PLB基因表达在两组间无显著差异(P>0.05)。心肌的SERCA与PLB表达量比值在6、8、10、12周龄出现显著大于同周龄WKY(P<0.05或P<0.01),而血管平滑肌的SERCA与PLB表达量比值在4、6、8、10、12周龄出现显著大于同周龄WKY(P<0.05或P<0.01)。结论:肌浆网SERCAmRNA表达改变及SERCA与PLB比例失常是高血压发生和发展过程中重要的分子生物学机制。     

Effects of mild calorie restriction on reproduction, plasma parameters and hepatic gene expression in mice with altered GH/IGF-I axis

The somatotropic axis, the hypothalamic-pituitary-gonadal axis and the nutritional status are deeply interrelated in mammals. Calorie restriction (CR) prolongs lifespan, but usually at some cost to reproduction. Interestingly, many of the physiological characteristics of animals with interruption in the somatotropic axis are shared by CR animals. The level of CR in most studies is 30-60%. We tested if a milder (20%) CR would promote health benefits without inhibiting reproduction in four types of mice with altered somatotropic axis: Ames dwarfs, GHR-KO, and PEPCK-bGH and MT-bGH transgenics. Fertility was not altered by CR in any of the examined groups. Mild CR did not affect final body weights or relative reproductive organ weights; did not alter plasma levels of glucose, insulin, IGF-I, testosterone, progesterone or estradiol; and did not influence hepatic expression of genes related to longevity. Altered activity of the GH/IGF-I axis in the different mice models studied had a major impact on the parameters analyzed. This preliminary study encourages speculation that mild regimens of CR can produce health and longevity benefits without the "costs" of impaired reproductive potential.     

Ghrelin对小鼠空间记忆和海马神经元突触及生长激素促分泌素受体表达的影响

目的 探讨Ghrelin对正常小鼠空间学习记忆能力和海马神经元突触及生长激素促分泌素受体（GHS-R）表达的影响。方法 8周龄小鼠 20只,随机分为实验组和对照组,分别腹腔注射Ghrelin和等量生理盐水,通过水迷宫实验检测小鼠的空间学习记忆能力,免疫组织化学实验检测海马Ghrelin受体GHS-R表达,并通过电子显微镜观察海马突触的超微结构变化。结果 水迷宫隐匿平台实验中,第2、3、4天,实验组小鼠的逃避潜伏期与对照组相比明显缩短（P <0.05）,跨越平台次数明显增加(P <0.05）,海马CA3和齿状回区GHS-R免疫阳性产物表达明显增强（P <0.05）,神经元突触数量明显增加（P <0.05）。结论 Ghrelin可能通过结合GHS-R,增加海马神经元突触数量,显著改善小鼠的空间学习记忆能力。     

转位肽/粒酶B融合蛋白基因的构建、表达及对细胞生长的抑制作用

目的：研究转位肽／粒酶B融合蛋白对细胞生长的抑制作用。方法：采用重组PCR法，将绿脓杆菌外毒素(PE)部分转位肽编码序列与活性型粒酶B(GrBa)基因相融合，构建PE Ⅱ-GrBa融合蛋白基因，以粒酶活性中心丝氨酸突变的PE Ⅱ—mGrBa作为阴性对照。将所获重组基因克隆入真核表达载体pcDNA3和pIRES2-EGFP中，以脂质体法瞬时转染Hela等细胞系，通过与GFP共表达，用MTT比色、TUNEL及间接免疫荧光染色，检测PE Ⅱ—GrBa基因的表达对转染细胞的形态和生长的影响。结果：表达PE Ⅱ—GrBa融合蛋白的细胞的细胞骨架发生异常，细胞生长受到抑制，部分细胞呈现凋亡特征。结论：PE Ⅱ—GrBa融合蛋白的表达可抑制细胞生长。     

表皮生长因子对肝星状细胞基质分解素－1及其抑制因子基因表达调节的影响

目的：了解表皮生长因子（EGF）对肝星状细胞基质分解素－1（MMP₃）及金属蛋白酶组织抑制因子－1（TIMP₁）基因表达的影响。方法：在培养的肝星状细胞系中加入EGF，于不同的时间点收集细胞，提取总RNA；用逆转录定量PCR方法测定基质分解素－1及TIMP₁的基因表达水平。结果：EGF组肝星状细胞MMP₃基因表达水平在8 h、24 h、48 h、72 h 4个时点均明显高于对照组；24 h达高峰，为对照组的3倍。EGF组肝星状细胞TIMP₁的基因表达水平在上述几个时点亦明显高于对照组；24 h达高峰，为对照组的2倍。结论：EGF在体外可增强肝星状细胞基质分解素－1及TIMP₁基因的表达。