溃疡愈合过程中表皮生长因子和转化生长因子α的表达。时间序列研究。

Expression of epidermal growth factor and transforming growth factor alpha during ulcer healing. Time sequence study.

作者信息

Konturek P C, Brzozowski T, Konturek S J, Ernst H, Drozdowicz D, Pajdo R, Hahn E G

机构信息

Dept. of Medicine I, University Erlangen-Nuremberg, Germany.

出版信息

Scand J Gastroenterol. 1997 Jan;32(1):6-15. doi: 10.3109/00365529709025056.

DOI:10.3109/00365529709025056

PMID:9018760

Abstract

BACKGROUND

Growth factors such as epidermal growth factor (EGF) and transforming growth factor alpha (TGF alpha) have been shown to share common receptor (EGFR) and to accelerate ulcer healing due to stimulation of cell proliferation, but the time sequence of expression of EGF and TGF alpha during ulcer healing has not been investigated. In this study the rate of cell proliferation and the gastric secretion and gene expression of mRNA for EGF and TGF alpha were determined during ulcer healing.

METHODS

Gastric ulcers were induced in 150 Wistar rats by serosal application of 100% acetic acid (ulcer area, 14 mm2). Some of these animals were also equipped with a gastric fistula for the assessment of gastric secretion during ulcer healing. The animals were killed 0, 2, 4, 6, or 8 days after ulcer induction, and the ulcer area was determined. The mucosal sections with gastric ulcer were immunostained for proliferating cell nuclear antigen (PCNA) and for immunoexpression of EGF, TGF alpha, and EGFR. The expression of mRNA EGF and mRNA TGF alpha was also determined in the ulcer margin by reverse transcriptase (RT) polymerase chain reaction (PCR) using specific primers.

RESULTS

Two, 4, 6, and 8 days after ulcer induction the gastric ulcer area was gradually reduced from the initial size (day 0) by 47%, 70%, 80%, and 87%, respectively, and this was accompanied by an increase in PCNA with its maximum on day 4. The gastric acid and pepsin secretion was significantly reduced by 75% and 79%, respectively, on day 2 after ulcer induction but then the secretion tended to return to normal value by day 8. The expression of EGF, TGF alpha, and EGFR was negligible on day 0 but increased significantly during the healing, reaching maximum on day 4. Expression of EGF mRNA was detected on days 2, 4, and 6, and that of TGF alpha mRNA on days 2, 4, 6, and 8 after ulcer induction, with the most intense signals for both transcripts observed on day 2.

CONCLUSIONS

The enhancement in cell proliferation during ulcer healing may be mediated by increased release of EGF and TGF alpha; 2) the expression of EGF and TGF alpha mRNA precedes the overexpression of these growth factors at the ulcer margin during ulcer healing; and 3) the overexpression of growth factors coincides with the inhibition of gastric secretion and increased blood flow at the ulcer margin, indicating that these factors affect gastric secretion and blood flow in the course of ulcer healing.

摘要

背景

表皮生长因子（EGF）和转化生长因子α（TGFα）等生长因子已被证明具有共同受体（EGFR），并通过刺激细胞增殖加速溃疡愈合，但溃疡愈合过程中EGF和TGFα表达的时间顺序尚未得到研究。在本研究中，测定了溃疡愈合过程中的细胞增殖率、胃分泌以及EGF和TGFα的mRNA基因表达。

方法

通过向150只Wistar大鼠浆膜面涂抹100%乙酸诱导胃溃疡（溃疡面积14平方毫米）。其中一些动物还安装了胃瘘，用于评估溃疡愈合过程中的胃分泌。在溃疡诱导后0、2、4、6或8天处死动物，测定溃疡面积。对胃溃疡的黏膜切片进行增殖细胞核抗原（PCNA）免疫染色以及EGF、TGFα和EGFR的免疫表达检测。还使用特异性引物通过逆转录（RT）聚合酶链反应（PCR）测定溃疡边缘EGF mRNA和TGFα mRNA的表达。

结果

溃疡诱导后2、4、6和8天，胃溃疡面积从初始大小（第0天）分别逐渐减少47%、70%、80%和87%，同时PCNA增加，在第4天达到最大值。溃疡诱导后第2天胃酸和胃蛋白酶分泌分别显著减少75%和79%，但到第8天分泌趋于恢复正常。EGF、TGFα和EGFR在第0天表达可忽略不计，但在愈合过程中显著增加，在第4天达到最大值。溃疡诱导后第2、4和6天检测到EGF mRNA表达，第2、4、6和8天检测到TGFα mRNA表达，两种转录本在第2天观察到最强信号。