丁酸钠诱导人脑胶质瘤细胞系SHG-44凋亡的初步探讨

目的:研究短链脂肪酸盐丁酸钠对培养人脑胶质瘤细胞系SHG-44的增殖抑制和凋亡诱导.方法:通过细胞体外培养的方法,以2mmol/和4mmol/L丁酸钠处理SHG-44细胞,用MTT比色试验和PCNA免疫组化染色观察细胞增殖,电子显微镜、线粒体跨膜电位(△ψm)检测以鉴定细胞凋亡.结果:①SHG-44细胞增殖受到明显抑制,PCNA表达减弱;②4mmol/L丁酸钠明显诱导SHG-44细胞凋亡,电镜下可见细胞膜内陷自行分割包裹碎裂的核片段和部分胞浆,脱离细胞主体,形成凋亡小体;罗丹明123染色示凋亡细胞△ψm下降.结论:丁酸钠能抑制人脑胶质瘤SHG-44细胞的增殖,4mmol/L丁酸钠能诱导SHG-44细胞发生线粒体途径凋亡.     

结肠癌尿激酶分子系统调节作用的研究

目的研究转化生长因子β_1（TGF-β_1）和丁酸钠对结肠癌LoVo细胞的增殖、尿激酶型纤溶酶原激活剂（UPA）和纤溶酶原激活物抑制剂（PAI-1）的调节作用,探讨肿瘤浸润转移的机制。方法选择体外培养的LoVo细胞,分为对照组、TGF-β_1组、丁酸钠组、TGF-β_1＋丁酸钠组,分别在无血清培养条件下处理细胞,以~3H-TdR掺入法观察TGF-β_1和丁酸钠对细胞增殖的影响,并应用纤溶酶特异的发色底物法和酶联免疫测定法分别测定它们对结肠癌LoVo细胞UPA和PAI-1的调节作用,并同时观察不同条件处理后细胞形态和黏附度的变化。结果 TGF-β_1对LoVo细胞增殖无影响,但可增加UPA和PAI-1的含量。丁酸钠抑制细胞增殖和UPA活性,而不影响PAI-1的水平。结论 TGF-β_1通过提高UPA和PAI-1的水平促进肿瘤细胞的侵袭和转移。丁酸钠则可抑制细胞增殖和侵袭而阻止肿瘤发展。     

Upregulation of 25-hydroxyvitamin D3-1α-hydroxylase by butyrate in Caco-2 cells

AIM: To investigate the possible involvement of 25-hydroxyvitamin D3-1α-hydroxylase [1α-25(OH)2D3] in butyrate-induced differentiation in human intestinal cell line Caco-2 cells.METHODS: Caco-2 cells were incubated either with 3 mmol/L butyrate and 1 μmol/L 25(OH)2D3 or with 1μmol/L 1α-25(OH)2D3 for various time intervals ranging from 0 to 72 h. Additionally, cells were co-incubated with butyrate and either 25(OH)2D3 or 1α-25(OH)2D3.1α-25(OH)2D3 mRNA was determined semi-quantitatively using the fluorescent dye PicoGreen. Immunoblotting was used for the detection of 1α-25(OH)2D3 protein.Finally, enzymatic activity was measured by ELISA.RESULTS: Both butyrate and 1α-25(OH)2D3 stimulated differentiation of Caco-2 cells after a 48 h incubation period, while 25(OH)2D3 had no impact on cell differentiation. Synergistic effects on differentiation were observed when cells were co-incubated with butyrate and vitamin D metabolite. Butyrate transiently upregulated 1α-25(OH)2D3 mRNA followed by a timely delayed protein upregulation. Coincidently, enzymatic activity was enhanced significantly. The induction of the enzyme allowed for comparable differentiating effects of both vitamin D metabolites.CONCLUSION: Our experimental data pr ovide a further mechanism for the involvement of the vitamin D signaling pathway in colonic epithelial cell differentiation by butyrate. The enhancement of 1α-25(OH)2D3 followed by antiproliferative effects of the vitamin D prohormone in the Caco-2 cell line suggest that 25(OH)2D3 in combination with butyrate may offer a new therapeutic approach for the treatment of colon cancer.     

Phenylketonuric diet negatively impacts on butyrate production

Background and aims

Phenylalanine (Phe) restricted diet, combined with Phe-free l-amino acid supplementation, is the mainstay of treatment for phenylketonuria (PKU). Being the diet a key factor modulating gut microbiota composition, the aim of the present paper was to compare dietary intakes, gut microbiota biodiversity and short chain fatty acids (SCFAs) production in children with PKU, on low-Phe diet, and in children with mild hyperphenylalaninemia (MHP), on unrestricted diet.

Effect of Sodium Butyrate on Reactive Oxygen Species Generation by Human Neutrophils

Background: Short-chain fatty acids enema has been shown to be effective in the treatment of ulcerative colitis (UC). However, the mechanisms that lead to this response have not been well characterized. The aims of this study were to investigate the effect sodium butyrate has on reactive oxygen species (ROS) generation by human neutrophils, which are responsible for mucosal injury. Methods: Human neutrophils incubated with or without sodium butyrate were stimulated with opsonized zymosan (OZ) or phorbol myristate acetate (PMA). ROS generation was largely differentiated with flow cytometry assays of hydroethidine oxidation and dichlorofluorescein oxidation for superoxide anion and hydrogen peroxide respectively, and luminol-dependent chemiluminescence for myeloperoxidase-mediated oxidants. Results:     

丁酸钠对人绒毛膜癌JAR细胞生长抑制作用及其机制的实验研究

目的:探讨丁酸钠对人绒毛膜癌JAR细胞生长抑制作用及其可能机制。方法:通过流式细胞仪定量分析细胞周期分布及细胞凋亡;并采用酶联免疫吸附法(ELISA)检测丁酸钠对Fas蛋白表达水平的影响。结果:丁酸钠对JAR细胞生长有抑制作用,呈剂量依赖关系(P<0.05);丁酸钠组细胞凋亡率明显高于对照组(P<0.01);随着丁酸钠浓度升高,Fas蛋白的表达水平逐步升高(P<0.05)。结论:丁酸钠可以抑制人绒毛膜癌JAR细胞的生长和诱导其凋亡,其机制可能与Fas蛋白的高表达有关。     

Development of a Chronic Colonic Intubation Model in Rats for the Study of Luminal Factors in Colonic Diseases

INTRODUCTION: A rat model of long-term colonic intubation has been developed to facilitate the in vivo study of colonic biology. This study aims to characterize this model. METHODS: The effects of intubation and sham surgery on animal behavior and weight gain were measured and compared with unoperated controls. The reproducibility of the model was assessed by comparing complication and failure rates for three operators. The distribution and excretion of infused materials were studied using radiology and gas chromatography of feces, respectively. The effects of the colonic tube and infusions on the mucosa were assessed histologically. RESULTS: There was about 10 percent weight loss postoperatively, more marked in those rats undergoing more extensive surgery. Subsequent weight gain was similar in all groups, and no behavioral effects of surgery were noted. There were no differences in histologic appearances or proliferative indices among the groups. All three operators had similar complication and tube dislodgement rates. Radiologic examination showed even distribution of infusate regardless of fecal consistency. Infusion through the two tubes allowed the cecum and the distal bowel to be targeted differentially. The infusions did not alter the consistency of the fecal pellets or induce defecation. Gas chromatography at various time points after butyrate infusion showed a small, but statistically insignificant, rise in fecal excretion, representing less than 10 percent of the infused butyrate. CONCLUSIONS: A highly reproducible in vivo rat model, with an experimental life span of five to six weeks, has been achieved. Biological agents can be accurately delivered via the colonic tubes and are retained in the colonic segment of interest. This intubation model should provide a valuable tool in the future for in vivo studies of colonic biology.     

丁酸钠对胰腺癌BxPC-3细胞凋亡机制的影响

目的:探讨丁酸钠对胰腺癌BxPC-3细胞凋亡的影响及其作用机制。方法:采用MTT法观察不同浓度丁酸钠对BxPC-3细胞增殖的抑制作用;应用流式细胞仪检测丁酸钠作用于BxPC-3细胞后的凋亡情况;TRAP-ELISA法检测细胞端粒酶活性的变化;RT-PCR技术分析人端粒酶逆转录酶(hTERT)、bcl-2 mRNA的表达水平。结果:丁酸钠作用BxPC-3细胞能明显抑制细胞增殖,其作用具有时间和剂量依赖性。丁酸钠处理72 h的BxPC-3细胞凋亡率明显提高(P<0.01),S期细胞比例显著下降(P<0.05),G0/G1期细胞比例显著升高(P<0.05)。经丁酸钠处理的实验组端粒酶活性为0.96±0.12,未经丁酸钠处理的对照组端粒酶活性为4.18±0.34,二者之间差异有显著性(P<0.05)。丁酸钠处理的实验组hTERT mRNA水平为0.168±0.045,与对照组0.685±0.141比较差异有统计学意义(P<0.01),bcl-2实验组水平为0.138±0.034,与对照组0.715±0.026比较有统计学差异。结论:丁酸钠具有强烈诱导胰腺癌BxPC-3细胞凋亡的作用,其发生机制与丁酸钠下调hTERT Bcl-2 mRNA表达水平直接相关。