Expression of cellular fibronectin mRNA in adult periodontitis and peri-implantitis: a real-time polymerase chain reaction study

Cellular fibronectin （cFn） is a type of bioactive non-collagen glycoprotein regarded as the main substance used to maintain periodontal attachment. The content of cFn in some specific sites can reflect the progress of periodontitis or peri-implantitis. This study aims to evaluate the expression of cFn messenger RNA （mRNA） in tissues of adult periodontitis and peri-implantitis by real-time fluorescent quantitative polymerase chain reaction （PCR） and to determine its clinical significance. A total of 30 patients were divided into three groups of 10： healthy, adult periodontitis and peri-implantitis. Periodontal tissue biopsies （1 mmx I mmx I mm） from each patient were frozen in liquid nitrogen. Total RNA was extracted from these tissues, and the content, purity and integrity were detected. Specific primers were designed according to the sequence, and the mRNA expression levels of cellular fibronectin were detected by real-time PCR. The purity and integrity of the extracted total RNA were both high, and the specificity of amplified genes was very high with no other pollution. The mRNA expression of cFn in the adult periodontitis group （1.526＋0.441） was lower than that in the healthy group （3.253＋0.736）. However, the mRNA expression of cFn in the peri-implantitis group （3.965＋0.537） was significantly higher than that in the healthy group. The difference revealed that although both processes were destructive inflammatory reactions in the periodontium, the pathomechanisms were different and the variation started from the transcription level of the cFn gene.

Real-time polymerase chain reaction for the diagnosis of necrotizing herpes stromal keratitis

AIM： To design, optimize and validate a rapid,internally controlled real-time polymerase chain reaction（RT-PCR） test for herpes simplex virus（HSV） in the diagnosis of necrotizing herpes stromal keratitis.· METHODS： Tears alone or together with corneal epithelium scrapings from 30 patients（30 eyes）suspected of necrotizing herpes stromal keratitis were tested for HSV DNA by RT-PCR. The samples were collected during the first visit and then on the subsequent 7, 14, 28, 42, and 56 d. The symptoms of the patients were scored before treatment to determine the correlation between HSV concentration in the corneal epithelium scrapings and clinical scores.·RESULTS： The positive rate（46.4%） in the corneal epithelium group before the therapy was significantly higher than that（13.3%） in the tears group（P =0.006）.There were 13 positive HSV patients before the therapy,the concentration of HSV DNA in corneal epithelium scrapings group was significantly higher than that in the tears group（paired t-test, P =0.0397）. Multilevel mixedeffects model analysis showed that the difference between the corneal epithelium scrapings group and the tears group was statistically significant（P =0.0049）. The Spearman rank correlation analysis indicated a positive correlation between the HSV concentration in the corneal epithelium scrapings and clinical scores before the treatment（r =0.844, P〈 0.0001）.· CONCLUSION： RT-PCR appears to be a powerful molecular tool for the diagnosis of necrotizing herpes stromal keratitis.

Rapid genotyping of human rotavirus using SYBR green real-time reverse transcription-polymerase chain reaction with melting curve analysis

AIM: To develop a real-time reverse transcriptionpolymerase chain reaction(RT-PCR) assay to genotype rotavirus(G and P) in Alberta from January 2012 to June 2013. METHODS: We developed and validated a different approach to perform rotavirus G and P genotyping using a two-step SYBR green RT-PCR(rt-g PCR) by selecting genotype-specific primers of published conventional RT nested PCR(cn RT-PCR) assay and optimizing the amplification conditions. c DNA was first synthesized from total RNA with Super Script? Ⅱ reverse transcriptase kit followed by amplication step using monoplex SYBR green real-time PCR. After the PCR reaction, melting curve analysis was used to determine specific genotype. Sixteen samples previously genotyped using cn RT-PCR were tested using the new assay and the genotyping results were compared as sensitivity analysis. Assay specificity was evaluated by testing other gastroenteritis viruses with the new assay. The amplicon size of each available genotype was determined by gelelectrophoresis and DNA sequences were obtained using Sanger-sequencing method. After validation and optimization, the new assay was used to genotype 122 pediatric clinical stool samples previously tested positive for rotavirus using electron microscopy between January2012 and June 2013.RESULTS: The new rt-g PCR assay was validated and optimized. The assay detected G1 to G4, G9, G12 and P[4] and P[8] that were available as positive controls in our laboratory. A single and clear peak of melting curve was generated for each of specific G and P genotypes with a Tm ranging from 80 ℃ to 82 ℃. The sensitivity of rt-g PCR was comparable to cn RT-PCR with 100% correlation of the 16 samples with known G and P genotypes. No cross reaction was found with other gastroenteritis viruses. Using the new rt-g PCR assay, genotypes were obtained for 121 of the 122 pediatric clinical samples tested positive for rotavirus: G1P[8](42.6%), G2P[4](4.9%), G3P[8](10.7%), G9P[8](10.7%), G9P[4](6.6%), G12P[8](23.0%), and unknown GP[8](0.8%). For the first time, G12 rotavirus strains were found in Alberta and G12 was the second most common genotype during the study period. Gel electrophoresis of all the genotypes showed expected amplicon size for each genotype. The sequence data of the two G12 samples along with other genotypes were blasted in NCBI BLAST or analyzed with Rota C Genotyping tool(http://rotac.regatools.be/). All genotyping results were confirmed to be correct.CONCLUSION: rt-g PCR is a useful tool for the genotyping and characterization of rotavirus. Monitoring of rotavirus genotypes is important for the identification of emerging strains and ongoing evaluation of rotavirus vaccination programs.

Identifying the stability of housekeeping genes to be used for the quantitative real-time PCR normalization in retinal tissue of streptozotocin-induced diabetic rats

AIM:To investigate the stability of the seven housekeeping genes:beta-actin(ActB),glyceraldehyde-3-phosphate dehydrogenase(GAPDH),18s ribosomal unit 5(18s),cyclophilin A(CycA),hypoxanthine-guanine phosphoribosyl transferase(HPRT),ribosomal protein large P0(36B4)and terminal uridylyl transferase 1(U6)in the diabetic retinal tissue of rat model.METHODS:The expression of these seven genes in rat retinal tissues was determined using real-time quantitative reverse transcription polymerase chain reaction(RT-qPCR)in two groups;normal control rats and streptozotocininduced diabetic rats.The stability analysis of gene expression was investigated using geNorm,NormFinder,BestKeeper,and comparative delta-Ct(ΔCt)algorithms.RESULTS:The 36B4 gene was stably expressed in the retinal tissues of normal control animals;however,it was less stable in diabetic retinas.The 18s gene was expressed consistently in both normal control and diabetic rats’retinal tissue.That this gene was the best reference for data normalisation in RT-qPCR studies that used the retinal tissue of streptozotocin-induced diabetic rats.Furthermore,there was no ideal gene stably expressed for use in all experimental settings.CONCLUSION:Identifying relevant genes is a need for achieving RT-qPCR validity and reliability and must be appropriately achieved based on a specific experimental setting.

Real-time Fluorescence PCR Method for Detection of Burkholderia glumae from Rice

Burkholderia glumae causing seedling rot and grain rot of rice was listed as a plant quarantine disease of China in 2007. It＇s quite necessary to set up effective detection methods for the pathogen to manage further dispersal of this disease. The present study combined the real-time PCR method with classical PCR to increase the detecting efficiency, and to develop an accurate, rapid and sensitive method to detect the pathogen in the seed quarantine for effective management of the disease. The results showed that all the tested strains of B. glumae produced about 139 bp specific fragments by the real-time PCR and the general PCR methods, while others showed negative PCR result. The bacteria could be detected at the concentrations of 1×10^4 CFU/mL by general PCR method and at the concentrations below 100 CFU/mL by real-time fluorescence PCR method. B. glumae could be detected when the inoculated and healthy seeds were mixed with a proportion of 1：100.

转录介导的扩增技术与real-time RT-PCR在人类免疫缺陷病毒检测中的应用

目的:利用转录介导的扩增技术(transcription mediated amplification,TMA)扩增HIV RNA,探讨TMA技术扩增HIV RNA的敏感性及其与实时荧光定量反转录聚合酶链反应的比较。方法:利用Taq Man探针、特异性引物、鼠白血病反转录酶、T7-RNA聚合酶及PCR底物等建立TMA扩增体系。通过扩增一组10倍梯度稀释的HIV RNA转录标准品,评价TMA体系的灵敏性。收集60例HIV感染患者的血浆,同时采用TMA试剂与Cobas Amplicor HIV-1 Monitor 1.5版试剂进行检测,比较两种方法的阳性检出率,并利用线性回归和Bland-Altman法分析两种技术的相关性和一致性。结果:成功建立了TMA扩增体系,这种技术可以检测低至10 copies/m L的HIV转录标准品。60份HIV感染者血浆样本中,TMA及Cobas均检测到阳性46份,均阴性12份,TMA检测阴性而Cobas检测阳性样本2份,检测一致率为96.7%。两种技术阳性检出率差异无统计学意义(P>0.05)。对其中46份TMA检测和Cobas检测均有定量结果的血浆进行线性回归分析,两种技术有非常好的相关性(r=0.997,P<0.001)。Bland-Altman分析显示两种检测方法定量Lg差值平均值为0.02,44份(95.7%)样本在95%的一致性界限内。结论:TMA技术具有高灵敏性潜能。TMA与real-time RT-PCR检测血浆中HIV RNA具有非常好的相关性与一致性。

Use of real-time polymerase chain reaction for the diagnosis of Pneumocystis pneumonia in immunocompromised patients： a meta-analysis

Background The diagnosis of Pneumocystis pneumonia （PCP） in immunocompromised patients is still challenging today due to the absence of an in vitro culture system and the low diagnostic accuracy of microscopic examinations. Herein, we performed a meta-analysis to evaluate the accuracy of real-time polymerase chain reaction （PCR） in the diagnosis of PCP. Methods We searched Web of Knowledge and Medline from 1990 to May 2010 for studies reporting diagnostic accuracy data regarding the use of real-time PCR in the diagnosis of PCP in immunocompromised patients. Results Ten individual studies were included. Overall, the sensitivity of real-time PCR was 97% （95% CI： 93%-99%）; the specificity was 94% （95% CI： 90%-96%）. The area under the HSROC curve （95% CO for real-time PCR was 0.99 （0.97-0.99）. In a subgroup analysis regarding studies involving HIV patients among the study population, the sensitivity and specificity were 97% （95% CI： 93%-99%） and 93% （95% CI： 89%-96%）, respectively. Regarding studies using Bronchoalveolar lavage （BAL） samples only： sensitivity =98% （95% CI： 94%-99%）; specificity =93% （95% CI： 89%- 96%）, respectively. Regarding studies using microscopy as a reference standard： sensitivity =97% （95% CI： 92%-99%）; specificity =93% （95% CI： 88%-96%）. However, high between-study statistical heterogeneity was observed in all analyses. Conclusions Real-time PCR has a good diagnostic accuracy and may provide a useful adjunctive tool for the diagnosis of PCP in immunocompromised patients. Further studies are needed in order to identify any differences in the diagnostic performance of real-time PCR in HIV and non-HIV immunocompromised patients.

RT-qPCR normalization of reference genes in different lifehistory stages of Gracilaria vermiculophylla(Rhodophyta)

The quantitative realtime polymerase chain reaction(RT-qPCR)is a powerful and sensitive method to measure expression of targeted gene but it highly relies on the use of suitable reference genes for data normalization.We evaluated the expressions of 8 housekeeping genes:18S ribosomal rDNA(18S rDNA),28S ribosomal r DNA(28S rDNA),rubisco large subunit(rbc-L),β-actin(ACT),glyceraldehyde-3-phosphate dehydrogenase(GAPDH),elongation factor 1(EF1),β-tubulin(Tub B),and P-phycoerythrin B(PEB),to select the suitable reference genes for different life-history stages(tetrasporophyte,carposporophyte,and male/female gametophyte)of Gracilaria vermiculophylla by absolute quantitative method.Softwares geNorm and BestKeeper were used to verify the results acquired from copy number analysis.Results show that the expression of identified reference genes varied in comparing groups composed of different type of life stages.It is suggested that 18S rDNA and TubB could be used for highly complex samples composed of mixed ploidy and phases.18S rDNA and 28S rDNA were also preferred for using among the matured isomorphic samples.But for samples with different maturities,TubB and ACT were recommended for tetrasporophytes and gametophytes respectively.

SMRT sequencing and ddPCR reveal the complexity of developmental trajectories and temporal dynamics of gut bifidobacterial communities in infants

Infant intestinal microbiome is closely linked with health and risk of disease. Bifidobacterium are important components of the infant gut and are known to confer various health effects on the host. However, few studies have described the precise composition and dynamics of early infant gut bifidobacterial communities. Thus, this was a pilot study aiming to describe the developmental trajectories and temporal dynamics of bifidobacterial communities in infants before 6 months of age. A total of 28 fecal samples from 4 infants(GF, ZZ, QM, TN, respectively)were collected and analyzed after 5, 15, 30, 60, 90, 120, 150, and 180 days of birth by a bifidobacteria-target method(based on single-molecule real-time sequencing of partial bifidobacterial rpsK genes)in conjunction with droplet digital polymerase chain reaction(ddPCR). The infant fecal microbiota comprised a total of 11 bifidobacterial species, including 4 major species, i.e., B. dentium(37.35%), B. catenulatum(32.04%), B. breve(22.24%), and B. animalis(8.02%). The infant microbiota showed highly individualized developmental trajectories. The leading species for GF was B. catenulatum, with a relatively stable developmental trajectory. In ZZ, B. breve was enriched, and the developmental trajectory was rather fluctuating. The most abundant species for QM and TN was B. dentium. The developmental trajectory of B. dentium in QM showed a trend of gradual decrease, whereas an opposite trend was seen in samples of TN. The results of ddPCR confirmed large variations in quantities of bifidobacteria between infants and suggested discordances in temporal dynamics of bifidobacterial communities during the first half year of infancy. In conclusion, our results suggested that the early infant gut bifidobacterial microbiota was highly complex and temporal dynamics, with individualized developmental trajectories, which should be considered in future research of infant gut microbiota.

实时荧光定量PCR定量方法研究进展

实时荧光定量PCR以其特异性强、灵敏度高、重复性好、定量准确、速度快、全封闭反应等优点而成为了分子生物学研究中的重要工具,综述了实时荧光定量PCR技术及其定量方法的研究进展,并展望了其应用前景。

复方红景天对大鼠肝纤维化肝脏中TIMP-1表达的影响

目的:探讨复方红景天对四氯化碳(CCl4)诱导的大鼠肝纤维化肝组织TIMP-1基因表达的影响.方法:健康♂SD大鼠80只随机分组:(1)正常对照组;(2)肝纤维化模型组;(3)复方红景天高剂量组(H组);(4)复方红景天中剂量组(M组);(5)复方红景天低剂量组(S组),每组16只.以CCl4ip法诱导大鼠肝纤维化,复方红景天干预组大鼠在造模的同时给予复方红景天灌胃,正常对照组给予橄榄油sc和生理盐水ip,8wk实验结束时处死动物,留取的肝脏组织做HE按0-4期标准判定肝纤维化程度,应用半定量RT-PCR检测肝组织中TIMP-1 mRNA的表达情况,用免疫组化检测肝组织中TIMP-1的表达.结果:模型组大鼠肝纤维化程度处于2-4期,其中大部分达3期以上,复方红景天干预组大鼠肝纤维化程度明显减轻,只有少部分达3期.模型组大鼠肝组织中TIMP-1 mRNA水平高于正常对照组(0.858±0.052 vs 0.615±0.067,P<0.05),而复方红景天干预组大鼠肝组织中TIMP-1 mRNA水平(0.740±0.081,0.704±0.032,0.695±0.030)显著低于模型组(均P<0.05);模型组大鼠肝组织TIMP-1的阳性表达显著强于正常对照组(0.356±0.052 vs 0.121±0.067,P<0.05),复方红景天干预组肝组织中TIMP-1的阳性表达(0.298±0.081,0.256±0.032,0.213±0.030)明显强于正常对照组(均P<0.05),但较模型组显著减弱(P<0.05).结论:中药复方红景天能有效抑制CCl4诱导的肝纤维化大鼠肝脏中TIMP-1的表达.

Dysadherin、E-cadherin在宫颈癌中的表达及意义

目的:探讨宫颈癌中dysadherin、E-cadherin的表达及意义。方法:免疫组化及RT-PCR法检测宫颈癌组织中两者蛋白和mRNA表达水平。结果:宫颈癌组dysadherin蛋白表达高于正常组,E-cad表达低于正常组(P<0.05)。dysadherin蛋白高表达及E-cad蛋白低表达与宫颈癌病理分级、临床分期及淋巴结转移相关(P<0.05),而与年龄无关(P>0.05)。宫颈癌组dysadherin mRNA表达(1.05±0.14)高于正常组(0.91±0.09),E-cad mRNA表达(0.64±0.07)低于正常组(0.89±0.11)。dysadherin与E-cad表达呈负相关。结论:联合dysadherin、E-cad检测可作为宫颈癌诊断的辅助指标。

转基因细胞模型L02/HBx的构建及HBx对细胞周期的影响

目的:构建L02/HBx转基因细胞模型并研究HBx对肝细胞周期的影响.方法:运用脂质体转染和G418筛选获得L02/ HBx阳性克隆,并分别用RT-PCR和Western blot鉴定HBx mRNA与蛋白的表达.进一步用四唑蓝(MTT)比色试验、流式细胞仪检测L02/HBx的增殖、凋亡和细胞周期.结果:RT-PCR和Western blot分别检测到L02/ HBx细胞中HBx mRNA和蛋白的表达.MTT比色试验显示L02/HBx生长速度加快,流式细胞仪检测发现L02/HBx凋亡率低(0.09%±0.13% vs 3.74%±1.29%,P<0.05),G1期细胞比例减少(61.35%±0.82% vs 67.80±6.84%,P<0.05),S期细胞比例相应增加(36.59%±2.54% vs 22.37%±2.17%,P<0.05).经阿霉素(ADM)培养后,L02/HBx的凋亡率显著增加(34.91%±5.85% vs 0.09%±0.13%,P<0.05),G1期细胞比例明显增加但低于对照组(82.81%±6.48% vs 61.35%±0.82%,P<0.05;82.81%±6.48% vs 87.19%±1.92%,P<0.05),S期细胞比例降低但较对照组高(13.84%±6.16% vs 36.59%±2.54%,P<0.05;13.84%±6.16% vs 2.22%±1.26%,P<0.05).结论:L02/HBx构建成功,HBx能促进细胞周期进程,加快细胞的生长并抑制细胞的凋亡;转染HBx基因的肝细胞凋亡更易受凋亡因子所触发,表明HBx可能会增加正常肝细胞对诱导凋亡因素的敏感性.

ERCC1蛋白及mRNA在食管鳞癌中的表达及临床意义

目的:通过检测ERCC1蛋白及mRNA在食管癌、癌旁组织中的表达,初步探讨其与食管癌发生发展、侵袭转移之间的关系。方法:采用免疫组化(SP法)染色法及逆转录-聚合酶链反应(RT-PCR法)对62例食管癌及部分病例相应的36例癌旁组织中的ERCC1蛋白及mRNA的表达进行检测,并行统计学分析。结果:ERCC1蛋白及mRNA在食管癌组织中的表达均高于癌旁组织(对照组),且与癌组织的浸润程度、淋巴结转移、癌组织分化程度及临床预后密切相关(P<0.05)。结论:ERCC1的表达与食管癌发生发展、侵袭转移关系密切,可作为食管癌患者的个体化治疗及临床预后判定的病理学指标之一。

MDR基因在食管癌中表达的临床意义

目的 探讨食管癌患者肿瘤组织中多药耐药 (MDR)基因表达及其在临床上的应用价值。方法 采用逆转录 -聚合酶链反应 (RT -PCR)检测 5 0例食管癌组织中的mdr - 1基因表达水平 ,同时检测 10例正常食管组织中的mdr- 1表达水平。结果 mdr- 1基因在食管癌高、中、低分化之间的表达水平具有极显著差异 (P <0 .0 1和 P <0 .0 0 1) ,癌与正常组织中有极显著差异 (P <0 .0 0 1) ;在不同年龄、性别及临床分期之间无显著差异 (P >0 .0 5 )。结论 mdr- 1基因的检测可预测患者对化疗的敏感性 ,使化疗个体化 。

大鼠急性肺栓塞模型中CA3和NHE_1表达的变化

目的研究大鼠急性肺栓塞模型肺组织中与酸碱平衡相关的碳酸酐酶3(CA3)和Na+/H+交换器(NHE1)的表达变化。方法建立大鼠急性肺栓塞模型,分别在急性肺栓塞后1、8、24和48 h开胸取出肺组织,然后提取肺组织的总RNA和总蛋白,以正常组为对照,采取半定量RT-PCR的方法研究CA3和NHE1在mRNA水平表达的变化;采用western-b lot方法进一步验证CA3和NHE1在蛋白水平表达的变化;同时采用免疫组织化学的方法检测大鼠肺组织中NHE1在肺栓塞前后表达的变化。结果在大鼠急性肺栓塞后的不同时间点,CA3的mRNA水平和蛋白水平均逐渐降低,而NHE1在mRNA水平和蛋白水平的表达都出现逐渐升高现象。免疫组化研究表明NHE1主要分布在支气管黏膜上皮和细支气管黏膜上皮的胞浆内,急性肺栓塞后NHE1在上皮细胞内的表达明显升高。结论大鼠急性肺栓塞后肺组织内CA3的表达降低,NHE1的表达升高,这一现象可能与机体的酸碱平衡调节相关。

LAMP与RT-PCR法检测痰结核分枝杆菌的效果比较

目的比较环介导等温扩增技术(LAMP)和实时荧光PCR技术(RT-PCR)检测结核分枝杆菌的效果。方法可疑肺结核患者痰标本118份,分别采用痰涂片镜检、罗氏固体培养基培养、LAMP、RT-PCR方法进行结核分枝杆菌检查。结果结核分枝杆菌阳性检出率痰涂片镜检38%、罗氏固体培养基培养41%、LAMP45%、RT-PCR 55%,4种方法阳性检出率比较差异有统计学意义(P<0.05);以常规罗氏固体培养法为标准,LAMP法的灵敏性和特异性分别为92.0%(46/50)和86.8%(59/68),与罗氏培养法比较差异无统计学意义(P>0.05),一致性强(Kappa=0.777);PCR法的灵敏性和特异性分别为86.0%(43/50)和66.2%(45/68),与罗氏培养法比较差异有统计学意义(P<0.01)。结论 RT-PCR检测法阳性率最高,但特异性低;LAMP法灵敏性和特异性较高,与传统培养法一致性好,操作简便易行、快速准确。

Streptomyces sahachiroi ATCC 33158中一个Ⅲ型聚酮合酶基因的克隆及功能分析

从链霉菌Streptomyces sahachiroi ATCC 33158基因组中克隆到1个聚酮合酶(polyketide synthase,PKS)基因orf18。生物信息学及进化树分析表明它可能属于rppA类Ⅲ型PKS基因。通过RT-PCR证实了该基因在野生型S.sahachiroi中是可以进行转录表达的。HPLC和LC-MS分析的结果表明orf18在S.lividans中异源表达时可产生1,3,6,8-四羟基萘(THN),并且发现该基因也可以在革兰氏阴性菌Pseudomonas stutzeri中异源表达并产生明显的棕红色色素。证明orf18编码的蛋白属于RppA类Ⅲ型PKS,可催化THN的合成,而产物THN在革兰氏阴性菌P.stutzeri中可进一步氧化及聚合形成棕红色色素。

Expression of matrix metalloproteinases 2 and 9 in human gastric cancer and superficial gastritis

AIM:To assess expression of matrix metalloproteinases 2(MMP2)and MMP9 in gastric cancer,superficial gastritis and normal mucosa,and to measure metalloproteinase activity.METHODS:MMP2 and MMP9 mRNA expression was determined by quantitative real-time polymerase chain reaction.Normalization was carried out using three different factors.Proteins were analyzed by quantitative gelatin zymography(qGZ).RESULTS:18S ribosomal RNA(18SRNA)was very highly expressed,while hypoxanthine ribosyltransferase-1(HPRT-1)was moderately expressed.MMP2 was highly expressed,while MMP9 was not detected or lowly expressed in normal tissues,moderately or highly expressed in gastritis and highly expressed in cancer.Relative expression of 18SRNA and HPRT-1 showed no significant differences.Significant differences in MMP2 and MMP9 were found between cancer and normal tissue,but not between gastritis and normal tissue.Absolute quantification of MMP9 echoed this pattern,but differential expression of MMP2 proved conflictive.Analysis by qGZ indicated significant differences between cancer and normal tissue in MMP-2,total MMP-9,250 and 110 kDa bands.CONCLUSION:MMP9 expression is enhanced in gastric cancer compared to normal mucosa;interpretation of differential expression of MMP2 is difficult to establish.

Involvement of interstitial cells of Cajal in experimental severe acute pancreatitis in rats

AIM:To observe the changes in interstitial cells of Cajal(ICC) in rats with experimental severe acute pancreatitis(SAP).METHODS:A total of twenty-four SD rats were randomly divided into two groups(n = 12),namely the sham(S) group and the SAP group;the SAP rat model was established by retrograde injection of 5% sodium taurocholate(1.0 mL/kg) into the pancreatic duct.Twenty-four hours later intestinal motility was assessed by testing small intestinal propulsion rate,and then the rats were sacrificed.The pancreas and jejunum were resected and underwent routine pathologic examination.Immunohistochemical staining was used to detect c-kit-positive cells in the jejunum.Expression of c-kit mRNA was detected by real-time polymerase chain reaction,and the expression of c-kit protein was evaluated by Western blotting.Ultrastructure of ICC was evaluated by transmission electron microscopy.RESULTS:There was bleeding,necrosis and a largeamount of inflammatory cell infiltration in pancreatic tissue in the SAP group,while in jejunal tissue we observed a markedly denuded mucosal layer,loss of villous tissue and a slightly dilated muscular layer.The small intestinal propulsion rate was 68.66% ± 2.66% in the S group and 41.55% ± 3.85% in the SAP group.Compared with the S group,the rate of the SAP group decreased sharply.The density of c-kit-positive cells in the SAP group was significantly lower than in the S group;the respective mean densities were 88.47 ± 10.49 in the S group and 56.11 ± 7.09 in the SAP group.The levels of c-kit protein and mRNA were 0.36 ± 0.04 and 1.29 ± 0.91 in the SAP group,respectively,which were significantly lower than those in the S group(0.53 ± 0.06,0.64 ± 0.33,respectively).In the SAP group,ICC profiles showed the same change tendency,such as vacuolation of mitochondria,irregular vacuoles and loosened desmosome-like junctions.CONCLUSION:Decreased c-kit-positive cells and ultrastructural changes in ICC resulting from blockade of the c-kit signaling pathway are involved in the intestinal dysmotility associated with SAP.