模拟失重对大鼠实验性胃溃疡愈合的影响

Effect of simulated weightlessness on the healing of experimental gastric ulcer in rats

目的:探讨模拟失重对乙酸诱导的大鼠实验性胃溃疡愈合的影响及可能机制.方法:32只SD大鼠随机分为4组,即尾部悬吊7d组、尾部悬吊14d组和相应的同步对照组.采用乙酸烧灼法制备大鼠慢性胃溃疡模型,造模后第3天悬吊组大鼠采用尾悬吊法建立模拟失重动物模型.游标卡尺检测胃溃疡面积,电镜下观察再生黏膜结构,放免法检测胃液EGF含量,观察大鼠胃溃疡愈合分期.结果:与对照7d组相比,悬吊7d组大鼠溃疡面积明显增大(6.0mm2±1.7mm2vs2.2mm2±0.7mm2,t=5.661,P<0.01),溃疡分期明显降低(χ2=12.771,P<0.01);与对照14d组相比,悬吊14d组溃疡面积明显增大(3.0mm2±1.2mm2vs1.1mm2±0.4mm2,t=4.233,P<0.01),胃液EGF含量明显增高(0.155ng/mL±0.052ng/mLvs0.103ng/mL±0.019ng/mL,t=2.635,P<0.05);与悬吊7d组比较,悬吊14d组溃疡面积明显减小(3.0mm2±1.2mm2vs6.0mm2±1.7mm2,t=3.805,P<0.01),胃液EGF含量明显降低(0.155ng/mL±0.052ng/mLvs0.434ng/mL±0.137ng/mL,t=5.657,P<0.01),溃疡分期明显降低(χ2=12.953,P<0.01).与对照7d组、14d组相比,悬吊7d组、14d组再生黏膜结构的恢复差,组织学成熟度降低.结论:模拟失重可降低再生黏膜结构,延迟溃疡愈合,胃液EGF含量可出现代偿性增加.

AIM： To investigate the effect of simulated weightlessness on the healing of acetic acidinduced experimental gastric ulcer in rats and to explore the potential mechanisms involved. METHODS： Thirty-two SD rats were randomly and equally divided into four groups： 7 d tail suspension group, 7 d control group,14 d tail suspension, and 14 d control group. Gastric ulcer was induced in rats with acetic acid. Tail suspension was used to simulate the weightlessness condition 3 days after ulcer induction. The gastric ulcer area was measured with a verniercaliper. The ultrastructure of regenerative mucosa was observed by electronic microscopy. Epidermal growth factor （EGF） level in gastric juice was determined by radioimmunoassay （RIA）. The staging of ulcer healing was performed. RESULTS： Compared to the 7 d control group, the ulcer area significantly increased （6.0 mm^2± 1.7 mm^2 vs 2.2 mm^2 ± 0,7 mm^2, t = 5.661, P 〈 0.01） and the stage of ulcer significantly decreased （X^2 = 12.771, P 〈 0.01） in the 7d suspension group. Compared to the 14 d control group, the ulcer area and EGF level increased （3.0 mm^2 ± 1.2 mm^2 vs 1.1 mm^2 ±0.4 mm^2, t = 4.233, P 〈 0.01; 0.155 ng/mL± 0.052 ng/mL vs 0.103 ng/mL ±0.019 ng/mL, t = 2.635, P 〈 0.05） in the 14 d suspension group. Compared to the 7 d suspension group, the ulcer area, EGF level and stage of ulcer significantly decreased （3.0 mm^2±1.2 mm2 vs 6.0 mm2 ±1.7 mm2, t = 3.805, P 〈 0.01; 0.155 ng/mL ± 0.052 ng/mL vs 0.434 ng/mL ± 0.137 ng/mL, t = 5.657, P 〈 0.01; X^2 = 12.953, P 〈 0.01） in the 14 d suspension group. The ultrastructural restoration and histological maturity of healed ulcer in the 7 d and 14 d suspension groups were inferior to those in the 7 d and 14 d control groups. CONCLUSION： Simulated weightlessness may depress the structure of regenerative gastric mucosa, delay the healing of ulcer, and increase EGF level in gastric juice.