ERK通路在塞来昔布延缓乙酸性大鼠胃溃疡愈合中的作用

Effects of ERK signal transduction pathway on delaying the healing of acetic acid-induced gastric ulcer by Celecoxib in rats

目的明确选择性环氧合酶-2(COX-2)抑制剂塞来昔布对乙酸性大鼠胃溃疡愈合的影响,并从ERK通路的角度探讨其延缓胃溃疡愈合的机制。方法将48只Wistar大鼠分为模型组(40只)和假手术对照组(8只)。模型组进行乙酸性胃溃疡制模术,假手术对照组行假手术。术后第3天,处死模型组和假手术对照组各8只大鼠。模型组剩余的32只大鼠再随机分为塞来昔布组和生理盐水组。塞来昔布组从制模术后第3天开始胃内灌注0.2%塞来昔布溶液1ml,生理盐水组灌注等量生理盐水。制模术后第6天和第9天,每次处死塞来昔布组和生理盐水组各8只大鼠,观察塞来昔布对胃溃疡愈合的影响,Western blotting检测其对胃黏膜Raf-1、ERK1/2活性及下游转录因子c-Fos、c-Jun蛋白水平的影响。结果制模术后第9天,生理盐水组和塞来昔布组的溃疡面积分别为11.9±3.1mm2和19.7±3.8mm2,与第3天(33.3±7.4mm2)相比均明显缩小(P<0.01),其中塞来昔布组溃疡面积约为生理盐水组的1.7倍。制模术后第6天和第9天,塞来昔布组Raf-1和ERK1/2活性及c-Fos蛋白水平均显著低于生理盐水组(P<0.01),而两组在上述两个时间点上c-Jun蛋白水平均无显著性差异。结论塞来昔布可能是通过抑制ERK通路的活化而发挥延缓胃溃疡组织增生修复的作用。

Objective To investigate the effects of Celecoxib, a selective COX-2 inhibitor, on the healing of gastric ulcer in rats, and reveal the rale of ERK signal transduction pathway in the mechanism of delaying the healing of gastric ulcer. Methods Forty-eight rats were randomly divided into model group （n=40） and sham operation group （n=8）. In the rats in model group acetic acid-induced gastric ulcer was reproduced, while in sham operation group, rats underwent the sham procedure. Eight rats in sham-operation group and eight rats in model group were euthanized three days after the procedure. The other thirty-two rats in model group were divided into two subgroups including Celecoxib group and NS group （n= 16）. Three days after the procedure, rats in Celecoxib group received a gavage of 0.2% Celecoxib solution, and those in NS group received equal amount of 0.9% NaCl solution. Rats in Celecoxib group and NS group were euthanized on sixth and ninth day after ulcer induction （8 rats at each time point in each group）. The effects of Celecoxib on the healing of gastric ulcer were observed. Its effects on the activity of Raf-1 and ERK1/2, and the expression level of two transcription factors c- Fos and c-Jun were also determined by Western blot analysis. Results Nine days after ulcer induction, the ulcer area was 11.9±3.1mm^2 and 19. 7±3. 8mm^2 in NS group and Celecoxib group, respectively, and they were much smaller than those on third day （P〈0.01）. The ulcer area in Celecoxib group was 1.7 folds of that in NS group. The activity level of Raf-1 and ERK1/2 and the expression level of c-Fos in Celeeoxib group decreased significantly compared with those in NS group on both 6th and 9th day after ulcer induction （P〈0. 01）, while there was no signifieam difference in the level of c-Jun protein in the two groups at either time point. Conclusion Selective COX-2 inhibitor Celecoxib may delay gastric ulcer healing through inhibiting the activation of ERK signal transduction pathway.