表皮生长因子及谷氨酰胺防治鼠乙酸性结肠炎的能量代谢研究

本文通过肌注表皮生长因子（EGF）和（或）饮饮谷氨酰胺（GLN），防治大鼠乙酸性结肠炎。结果提示联合应用EGF，GLN，能增强组织培养，提高ATP酶活性，促进肠粘膜细胞代谢和增生，防治结肠炎症，保护结肠粘膜细胞。     

Impaired nitrergic innervation in rat colitis induced by dextran sulfate sodium

BACKGROUND & AIMS: The pathophysiological role of neuronal nitric oxide synthase (nNOS) in colitis remains unknown. METHODS: We investigated colonic transit, nonadrenergic, noncholinergic (NANC) relaxation, nNOS activity, and nNOS synthesis in the myenteric plexus in dextran sulfate sodium (DSS)-induced colitis in rats. RESULTS: Oral administration of 5% DSS for 7 days induced predominant distal colitis and delayed colonic transit. In the proximal colon, carbachol-, sodium nitroprusside-, and electrical field stimulation (EFS)-induced responses were not different between control and DSS-treated rats. In the distal colon, EFS-evoked cholinergic contraction, NANC relaxation, and orphanin FQ-induced contraction were significantly impaired in DSS-treated rats compared with those in control rats, but carbachol- and sodium nitroprusside-induced responses remained intact in DSS-treated rats. The number of nNOS-immunopositive cells, catalytic activity of NOS, and nNOS synthesis in the colonic wall were significantly reduced in the distal colon of DSS-treated rats. In contrast, the number of PGP 9.5-immunopositive cells and PGP 9.5 synthesis in the colonic wall remained intact in the distal colon of DSS-treated rats. CONCLUSIONS: These results suggest that impaired NANC relaxation in the distal colon is associated with reduced activity and synthesis of nNOS in the myenteric plexus in DSS-induced colitis.     

Therapeutic effects of rectal administration of basic fibroblast growth factor on experimental murine colitis

BACKGROUND & AIMS: Basic fibroblast growth factor (bFGF) is a promising therapeutic agent for various diseases. It remains unclear, however, whether bFGF is effective for the treatment of inflammatory bowel disease. The aim of this study was to examine the efficacy of bFGF on 2 experimental murine colitis models and to investigate its molecular mechanisms. METHODS: We evaluated the effects of human recombinant bFGF (hrbFGF) on mice with dextran sulfate sodium (DSS)-induced colitis and mice with trinitrobenzene sulfonic acid (TNBS)-induced colitis as well as normal mice. Body weight, survival rate, and histologic findings of the colonic tissues were examined. Gene expression of tumor necrosis factor (TNF)-alpha, cyclooxygenase (COX)-2, transforming growth factor (TGF)-beta, mucin 2 (MUC2), intestinal trefoil factor (ITF), and vascular endothelial growth factor (VEGF) in the colonic tissues was determined. The proliferation activity of hrbFGF on the colonic epithelium was evaluated by immunohistochemistry. RESULTS: Rectal administration of hrbFGF ameliorated DSS-induced colitis in a dose-dependent manner. Gene expression of TNF-alpha was significantly reduced in the colonic tissues of mice with DSS-induced colitis treated with hrbFGF, whereas MUC2 and ITF messenger RNA expression was up-regulated. Rectal administration of hrbFGF significantly improved the survival rate of mice with TNBS-induced colitis and partially ameliorated colitis. hrbFGF significantly increased the number of Ki-67-positive cells in the colonic epithelium of normal mice, and up-regulated the gene expression of COX-2, TGF-beta, MUC2, ITF, and VEGF in the colonic tissues. CONCLUSIONS: Rectal administration of bFGF might be a promising option for the treatment of inflammatory bowel disease.     

大肠癌组织中表皮生长因子及受体的检测

本文应用免疫组化ABC法检测52例大肠癌和18例正常结肠组织中表皮生长因子（EGF）和表皮生长因子受体（EGF－R）的表达状况。正常组织中EGF阳性率22．2％，EGF－R阳性率16．7％，大肠癌EGF阳性率67．3％，EGF－R阳性率61．5％，二者均明显高于正常对照组织，（P＜0．05）。EGF和EGF－R阳性率与患者年龄，性别及肿瘤部位无明显相关，但随着肿瘤浸润度的加深，EGF与EGF－R的阳性率逐渐增高，有淋巴结转移者二者阳性率高于淋转阴性者，特别是EGF与EGF－R双阳者中有82．6％为进展期大肠癌，另发现低分化大肠癌中EGF和EGF－R阳性率明显低于中高分化癌。本文结果提示：部分大肠癌存在EGF或EGF－R的过度表达；EGF与EGF－R的过度表达与肿瘤润度及淋巴转移有关，其检测可作为诊断肿瘤恶性程度的一项辅助指标，部分正常大肠粘膜组织中也有少量EGF或EGF－R表达。     

Growth-promoting effect of muscarinic acetylcholine receptors in colon cancer cells

PURPOSE: G-protein-coupled receptors are known to mediate cell growth via divergent signaling pathways. It has been reported that colon cancer cells express muscarinic acetylcholine receptor (mAChR) although their functional role is largely unknown. The aim of this study is to elucidate possible mechanisms responsible for the growth-promoting effect of mAChRs in colon cancer cells by using colon cancer cell line T84. METHODS: Carbachol, a stable mAChR agonist, dose-dependently induced cell growth with a maximal effect observed at 100 microM, equipotent with 1 nM EGF. 4-DAMP, a specific antagonist of subtype 3 mAChR, inhibited the stimulatory effect by carbachol, suggesting that the growth-promoting effect was receptor-mediated. Carbachol also dose-dependently stimulated extracellular signal-regulated protein kinase (ERK) activation. This effect was inhibited by PD98059, an inhibitor of extracellular signal-regulated protein kinase kinase, which also blocked carbachol activation of cell proliferation, indicating that the p21Ras-ERK pathway is an important signaling cascade in the mitogenic effect. To investigate how mAChR activated the p21Ras-ERK pathway, transactivation of epidermal growth factor receptor (EGFR) was examined. RESULTS: Carbachol induced tyrosine phosphorylation of EGFR, which was abolished by an EGFR tyrosine kinase inhibitor AG1478. Transactivation by carbachol was also abrogated by a metalloproteinases (MMPs) inhibitor GM6001 or an EGFR-blocking antibody (LA-1), suggesting that binding of EGFR ligand(s) produced by MMPs may initiate transactivation in a manner dependent on EGFR tyrosine kinase. The tyrosine-phosphorylated EGFR was immunoprecipitated together with GRB2 and tyrosine-phosphorylated Shc, indicating that transactivated EGFR is able to generate downstream signals. AG 1478 and LA-1 inhibited carbachol stimulation of cell growth. CONCLUSIONS: Taken together, our results indicate that the growth-promoting effect of subtype 3 mAChR in colon cancer cells may depend on transactivated EGFR-ERK pathways. EGFR not only receives external stimuli but also serves as a scaffold for downstream signaling molecules.     

The vagus nerve: a tonic inhibitory influence associated with inflammatory bowel disease in a murine model

BACKGROUND & AIMS: The recently proposed Inflammatory Reflex describes an interaction between the vagus nerve and peripheral macrophages, resulting in attenuation of proinflammatory cytokine release in response to systemic exposure to bacterial endotoxin. The purpose of this study was to determine whether a similar vagus/macrophage axis modulates the inflammatory responses in the colon in mice. METHODS: We assessed the Disease Activity Index (DAI), macroscopic and histologic damage, serum amyloid-P level, and myeloperoxidase activity in colitis induced by administration of dextran sodium sulfate (DSS) in healthy and vagotomized C57BL/6 and in mice deficient in macrophage-colony stimulating factor (M-CSF)-induced and in hapten-induced colitis. A pyloroplasty was performed in vagotomized mice. RESULTS: DAI, macroscopic and histologic scores, myeloperoxidase activity, levels of serum amyloid-P, and colonic tissue levels of interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha were increased significantly in vagotomized mice 5 days post-DSS and 3 days after hapten-induced colitis compared with sham-operated mice that received DSS or the hapten. Pretreatment with nicotine significantly decreased each of these markers in vagotomized mice with DSS colitis, and all markers except DAI and IL-6 in sham-operated DSS-treated mice. Conversely, hexamethonium treatment significantly increased each of these markers in the sham-operated DSS-treated mice. Vagotomy had no effect on the colitis in M-CSF-deficient mice. CONCLUSIONS: The vagus nerve plays a counterinflammatory role in acute colitis via a macrophage-dependent mechanism, involving hexamethonium-sensitive nicotinic receptors. The identification of a counterinflammatory neural pathway would open new therapeutic avenues for treating acute exacerbations of inflammatory bowel disease.     

甲状腺增殖性疾患组织表皮生长因子及其受体的表达

目的　探讨表皮生长因子 (EGF)及其受体 (EGFR)在甲状腺增殖性疾患中的表达及其作用。方法　应用免疫组化ABC染色方法观察 70例甲状腺组织切片EGF及EGFR的表达。结果(1)EGF在正常、肿瘤及非肿瘤组织中几乎均无表达。 (2 )乳头状、滤泡型甲状腺癌及其混合癌EGFR阳性表达高于非癌疾患及正常组织 (P <0 .0 5 ) ,阳性表达程度以强阳性为主。 (3)在正常组织、良性腺瘤、结节性甲状腺肿及桥本病 ,弱或中度的EGFR阳性表达率各组间差异无显著性。正常组织阳性表达率虽高达 83.3 % ,但 2 / 3表达为弱阳性。 (4 )乳头状甲状腺癌以细胞浆表达EGFR占优势 ,滤泡型及混合型甲状腺癌主要为混合着色 ,但与非癌混合着色不同的是多数以胞浆表达占优势 ;良性疾患以混合染色为主 ,但结节性甲状腺肿以膜着色居多。正常组织为浆、膜混合着色。结论　 (1)对EGFR强阳性表达尤其细胞浆为主者应高度疑及甲状腺癌。 (2 )各甲状腺良性疾患均有不同程度EGFR表达 ,虽无统计学意义上的差别 ,却可说明EGFR对于良性肿瘤及非肿瘤增殖性疾患的生成均有不应忽视的作用。     

Clostridium difficile toxin B activates the EGF receptor and the ERK/MAP kinase pathway in human colonocytes

BACKGROUND & AIMS: Clostridium difficile toxin B (TxB) mediates acute inflammatory diarrhea characterized by neutrophil infiltration and intestinal mucosal injury. In a xenograft animal model, TxB was shown to induce interleukin (IL)-8 gene expression in human colonic epithelium. However, the precise mechanisms of this TxB response are unknown. The aim of this study was to investigate the TxB-mediated proinflammatory pathway in colonocytes. METHODS: The effect of TxB on epidermal growth factor receptor (EGFR), extracellular signal-regulated kinase (ERK) 1/2 signaling pathway and IL-8 gene expression was assessed in nontransformed human colonic epithelial NCM460 cells. TxB regulation of EGFR-ERK1/2 signaling pathways was determined using immunoblot analysis, confocal microscopy, and enzyme-linked immunosorbent assay, whereas IL-8 gene expression was measured by luciferase promoter assay. RESULTS: TxB activates EGFR and ERK1/2 phosphorylation with subsequent release of IL-8 from human colonocytes. Pretreatment with either the EGFR tyrosine kinase inhibitor, AG1478, or an EGFR-neutralizing antibody blocked both TxB-induced EGFR and ERK activation. By using neutralizing antibodies against known ligands of EGFR, we found that the activation of EGFR and ERK1/2 phosphorylation was mediated by transforming growth factor-alpha (TGF-alpha). Inhibition of matrix metalloproteinase (MMP) decreased TGF-alpha secretion and TxB-induced EGFR and ERK activation. Inhibition of MMP, EGFR, and ERK activation significantly decreased TxB-induced IL-8 expression. CONCLUSIONS: TxB signals acute proinflammatory responses in colonocytes by transactivation of the EGFR and activation of the ERK/MAP kinase pathway.     

Epstein–Barr Virus DNA Exacerbates Colitis Symptoms in a Mouse Model of Inflammatory Bowel Disease

Infection with EBV has been associated with various inflammatory disorders including inflammatory bowel diseases (IBD). Contribution of this virus to intestinal disease processes has not been assessed. We previously detected that EBV DNA triggers proinflammatory responses via the activation of endosomal Toll-like receptor (TLR) signaling. Hence, to examine the colitogenic potential of EBV DNA, we used the dextran sodium sulfate (DSS) mouse colitis model. C57BL/6J mice received either DSS-containing or regular drinking water. Mice were then administered EBV DNA by rectal gavage. Administration of EBV DNA to the DSS-fed mice aggravated colonic disease activity as well as increased the damage to the colon histologic architecture. Moreover, we observed enhanced expression of IL-17A, IFNγ and TNFα in colon tissues from the colitis mice (DSS-treated) given the EBV DNA compared to the other groups. This group also had a marked decrease in expression of the CTLA4 immunoregulatory marker. On the other hand, we observed enhanced expression of endosomal TLRs in colon tissues from the EBV DNA-treated colitis mice. These findings indicate that EBV DNA exacerbates proinflammatory responses in colitis. The ubiquity of EBV in the population indicates that possible similar responses may be of pertinence in a relevant proportion of IBD patients.     

Epidermal growth factor regulation of DNA synthesis in human colonic lamina propria lymphocytes

Epidermal growth factor (EGF) is a potent growth factor for many tissues including the gastrointestinal tract. EGF is present in the gut lumen and is absorbed through the mucosa in the developing animals. In addition, EGF has been found to alter the immune system. In this study, we investigated thein vitro effect of EGF on normal colonic lamina propria lymphocyte DNA synthesis and ornithine decarboxylase activity. Human colonic lamina propria lymphocytes were isolated by collagenase-EDTA digestion. The effect of EGF on Con A-stimulated lymphocyte thymidine incorporation was tested. We observed that EGF suppressed DNA synthesis and ornithine decarboxylase (ODC) activity in lamina propria lymphocytes. EGF did not alter the time course of thymidine incorporation into LPL stimulated by the combination of phorbol 12,13-dibutyrate (PDB) and ionomycin. Our data suggest that (1) EGF suppresses DNA synthesis in human colonic lamina propria lymphocytes as well as ODC activity and (2) this inhibition may be mediated through protein kinase C or calcium flux. We postulate that EGF may have a role in modulating the human gut immune system.This work was supported in part by grant CA43280 from the National Institutes of Health.     

小檗碱对永生化结肠细胞系生长的影响及其机制

目的 观察小檗碱对永生化结肠细胞系(IMCE)生长的影响,探讨其可能机制.方法 IMCE细胞在存在及不存在表皮生长因子(EGF)或TNFα的情况下加入小檗碱,以Ki-67免疫细胞化学染色对有增殖活性的细胞进行标记,采用原位末端转移酶标记技术分析细胞凋亡情况,以Western blot方法检测EGF受体(EGFR)和蛋白激酶B(Akt)及其磷酸化的水平.结果 (1)EGF组的IMCE细胞增殖活性较空白对照组增强,增殖细胞比例为(10.64±1.41)%,EGF+小檗碱组比例为(1.81±0.85)%,显著低于EGF组(P＜0.01),小檗碱组比例最低[(0.49±0.42)%].(2)小檗碱组与TNFα组的细胞凋亡比例分别为(8.47±2.52)%和(9.39±2.13)%,明显高于空白对照组[(0.27±0.30)%],P＜0.01.(3)EGF组的磷酸化EGFR(p-EGFR)明显增加,EGF+不同浓度小檗碱组的p-EGFR呈浓度依赖性下降.(4)TNFα组的磷酸化Akt(p-Akt)增加,TNF+不同浓度小檗碱组的p-Akt表达较TNFα组下降.结论 小檗碱具有抑制IMCE细胞增殖和促进凋亡的作用,这种作用可能与抑制EGFR和Akt磷酸化有关.

Abstract：

Objective To investigate the effects of Berberine on growth of Immorto-Min colonic epithelial cell line (IMCE) and explore its possible mechanisms. Methods IMCE cells were treated with Berberine in the absence or presence of epidermal growth factor (EGF) and TNFα. Ki-67 staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay were used to identify the cell proliferation and apoptosis respectively. Furthermore, Western blot analysis was performed to detect the epidermal growth factor receptor ( EGFR), protein kinase B (Akt) and their phosphorylation.Results ( 1 ) Proliferating activity of IMCE cells was increased after adding EGF and the proportion of cell proliferation was ( 10. 64 ± 1.41 ) %. The proportion was significantly lowed in EGF plus Berberine group [(1.81 ±0. 85)%] compared to the EGF group(P ＜0. 01 ), while the lowest was the Berberine group [(0.49 ± 0.42) %]. (2) The proportions of cell apoptosis were ( 8.47 ± 2. 52 ) % and (9. 39 ± 2. 13 ) %in the Berberine group and TNFt group respectively which were significantly higher compared to the normal control [(0. 27 ± 0. 30)%], both P ＜ 0. 01. (3) The phosphorylation of EGFR was significantly increased after adding EGF and p-EGFR was decreased in EGF plus Berberine group at a concentration-dependent manner. (4) Moreover, the phosphorylation of Akt was enhanced after addition of TNFα , while the phosphorylation in the TNFα and Berberine group was inhibited compared to the TNFα group. Conclusions Berberine may suppress the proliferation and promote the apoptosis of IMCE cells. The mechanisms may relate to the inhibition of the phosphorylation of EGFR and Akt.     

健中愈疡片对乙酸诱导胃溃疡大鼠表皮生长因子及其受体表达的影响

[目的]观察健中愈疡片对乙酸诱导胃溃疡大鼠血清表皮生长因子（EGF）水平和胃溃疡边缘表皮生长因子受体（EGFR）表达的影响。[方法]制备乙酸诱导大鼠胃溃疡模型，分别予健中愈疡片、雷尼替丁和0．85％氯化钠液治疗14d，用放射免疫分析法测定大鼠血清EGF水平，免疫组织化学染色法检测胃溃疡边缘EGFR表达。[结果]造模3d时，胃溃疡模型组大鼠的血清EGF水平明显高于正常对照组，胃溃疡边缘EGFR表达比正常对照组明显增加。治疗14d后，与雷尼替丁组和0．85％氯化钠液组比较，健中愈疡片组的血清EGF水平显著减少（P〈0．01），而胃溃疡边缘EGFR表达显著增加（P〈0．01）。[结论]血清EGF水平可以作为反映胃肠黏膜完整性的一个监控指标，健中愈疡片能够减少血清EGF水平和增加胃溃疡边缘EGFR表达，这可能是其加速乙酸诱导胃溃疡愈合的主要作用机制。     

Epidermal Growth Factor Receptor Is Increased in Rabbit Intestinal Brush Border Membrane After Small Bowel Resection

A defective epidermal growth factor receptor (EGFR) abrogates adaptation, while overexpression of EGFR or exogenous epidermal growth factor (EGF) enhances adaptation following small bowel resection (SBR). EGFR is predominantly located on the enterocyte basolateral membrane, yet luminal EGF is increased in injured mucosa. We hypothesized that EGFR is both increased and redistributed to the enterocyte brush border membrane (BBM) after SBR and that parenteral EGF will reverse this redistribution. Rabbits (N = 20) were subjected to sham operation or SBR. EGF or vehicle were administrated one week postoperatively to SBR rabbits, and the gut was harvested one week later. EGFR levels in intestinal crude extracts and purified BBM were determined by Western blot analysis. No difference in EGFR level was detected in the crude extract among any of the groups. SBR more than doubled EGFR amount in BBM (P < 0.006). Parenteral EGF did not influence this redistribution. Thus, EGFR is partially redistributed to the BBM in the mucosa of SBR rabbits, and parenteral EGF does not reverse this redistribution.     

Expression of Rab5a in hepatocellular carcinoma: Possible involvement in epidermal growth factor signaling

Aim: The Rab subfamily plays a role in intracellular transport. Rab5a is, in particular, involved in receptor-mediated endocytosis. Epidermal growth factor (EGF) is known to induce cell migration and promote invasion and angiogenesis. The EGF receptor (EGFR) is actively internalized upon the addition of EGF. The aim of the present study was to clarify the expression of Rab5a in hepatocellular carcinomas (HCC) and to examine its effect on EGF signaling. Methods: The expression of the Rab5a protein in HCC and corresponding non-tumorous tissues from 23 patients with HCC who had undergone surgical resection were analyzed by immunoblotting. A stable transfectant of Rab5a dominant negative (S34N) was established in a human hepatoma cell line, PLC/PRF/5 (PLC/PRF/5/Rab5aDN). Results: High expression (tumor/non-tumor (T/N) ratios >/= 1) of Rab5a protein in HCC compared to the paired non-tumortissues was recognized in 15 patients (65.2%) of 23 samples. The Rab5a antigen was diffusely expressed in the cytoplasm and membranes of the cancer cells. The membrane-associated Rab5a is also enhanced via overexpression in HCC. The EGF-induced endocytosis of EGFR and the phosphorylation of MAP kinase were inhibited in PLC/PRF/5/Rab5aDN cells. The migration of PLC/PRF/5/Rab5aDN cells induced by EGF was also significantly attenuated. Conclusions: These results indicate that the overexpression of Rab5a in HCC may play an important role in EGF signaling.     

Effect of Scutellariae Radix extract on experimental dextran-sulfate sodium-induced colitis in rats

AIM： To investigate the effect of Scutellariae Radix extract （SRE） on ulcerative colitis （UC） in rats induced by dextran-sulfate sodium （DSS）. METHODS： Colitis was induced in male Sprague-Dawley （SD） rats （170-180 g） by 4% dextran sulfate sodium （DSS, wt/v, MW 54000） in drinking water for 8 d. The treated rats received 4% DSS and SRE orally （100 mg/kg per day）. Control rats received either tap water or SRE only. Macroscopic assessment which included body weight changes, fecal occult blood and stool consistency were determined daily. At the appointed time, the rats were sacrificed and the entire colons were removed. The colon length and the myeloperoxidase （MPO） activity were measured. The severity of colitis was graded by morphological and histological assessments. The ion transport activity of the colonic mucosa was assessed by electrophysiological technique. RESULTS： Rats treated with oral administration of 4% DSS regularly developed clinical and macroscopic signs of colitis. Treatment with SRE relieved the symptoms, including the reduction in body weight, shortening 2nd ulceration of the colon. Administration of SRE also significantly reduced the histological damage induced by DSS. Moreover, the Isc responses of the colonic mucosa to forskolin, were suppressed after the induction of colitis. The stimulated ion transport activity of DSS-rats treated with SRE displayed significant improvement in the secretory responsiveness. CONCLUSION： SRE was effective in treating acute DSS- induced ulcerative colitis, as gauged by reduced clinical disease, improved macroscopic and histological damage scores, and enhanced recovery of normal colonic secretory function.     

Cysteine-rich domains of muc3 intestinal mucin promote cell migration, inhibit apoptosis, and accelerate wound healing

BACKGROUND & AIMS: Muc3 intestinal mucin contains an extracellular cysteine-rich domain with 2 epidermal growth factor (EGF)-like motifs. The aim of this study was to determine the functional properties of Muc3 proteins. METHODS: Glutathione S-transferase-fusion proteins containing both Muc3 EGF-like domains (m3EGF1,2) or truncated versions (m3EGF1 and m3EGF2) were purified from Escherichia coli. Mouse colon (young adult mouse colon) and human A431 and LoVo cells were examined for migration and tyrosine phosphorylation in response to recombinant proteins. LoVo cells were transfected with a human MUC3A transmembrane-EGF1,2 construct and a stable clone was isolated (LhM3c14). Endogenous MUC3A in LoVo was inhibited by specific small interfering RNA transfection. Apoptosis was quantitated by nuclear morphology or terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick-end labeling assay. Colitis was induced in mice by oral 5% dextran sodium sulfate or rectal 5% acetic acid, followed by enema treatments. RESULTS: m3EGF1,2 stimulated cell migration in all cell lines, but did not induce proliferation. Migration was inhibited by a tyrosine phosphorylation inhibitor, genistein, but not by the EGF receptor inhibitor, tyrphostin (AG1478). Inhibition of endogenous MUC3A in LoVo reduced baseline migration. Tyrosine phosphorylation of ErbB receptors was not observed after treatment of cells with m3EGF1,2. LoVo cells pretreated with m3EGF1,2 and transfected LhM3c14 cells showed reduced apoptosis in response to tumor necrosis factor alpha or Fas-receptor stimulation. Administration of m3EGF1,2 per rectum significantly reduced mucosal ulceration and apoptosis in experimental acute colitis. Truncated proteins m3EGF1 and m3EGF2 had no effect. CONCLUSIONS: The Muc3 mucin cysteine-rich domain plays an active role in epithelial restitution, and represents a potential novel therapeutic agent for intestinal wound healing.     

表皮生长因子受体在胶质瘤中的表达变化及其在细胞信号传导中的作用

目的观察胶质瘤组织及细胞U251中表皮生长因子受体（EGFR）的表达变化,探讨其在细胞信号传导通路中的作用。方法采用免疫组化SP法检测78例脑胶质瘤组织和U251中的EGFR。用EGF作用U251,MTT法检测U251细胞增殖情况,Western blot法检测U251中磷酸化EGFR（p-EGFR）。结果 78例胶质瘤组织中EGFR阳性表达率为66.67%（52/78）,且与胶质瘤的病理分级呈正相关（r=0.441,P〈0.05）。EGF作用后,U251细胞增殖显著、U251中p-EGFR水平明显提高（P均〈0.05）。结论胶质瘤组织、细胞中EGFR均呈过度表达。EGFR通过其介导的细胞信号传导通路促进细胞增殖,EGFR在细胞信号传导通路中发挥重要作用。