+Gz暴露对大鼠胃黏膜损伤及胃液表皮生长因子含量的影响

Effects of different +Gz exposure on the gastric mucosal lesions and the changes of EGF level in the gastric juice of the rats

目的探讨不同+Gz暴露值对大鼠胃黏膜的损伤和胃液EGF含量的影响,探讨高+Gz值暴露后大鼠胃黏膜损伤的可能发生的机制。方法 40只雄性Wistar大鼠随机分成4组:对照组+1Gz值(n=10)、+5 Gz值(n=10)、+10 Gz值组(n=10)、重复暴露组(n=10)。+5 Gz值组、+10 Gz值组各连续暴露5 min,重复暴露组亦为连续暴露:+5 Gz值1.5 min、+10 Gz值2 min、+5Gz值1.5 min。每组下离心机后,光镜下分别观察各组胃黏膜大体损伤程度,用游标卡尺检测胃黏膜损伤指数。放免法检测胃液EGF含量。结果各组胃黏膜损伤的严重程度:重复暴露组>+10Gz暴露组>+5Gz暴露组>对照组。+5Gz暴露组与对照组相比胃黏膜损伤指数无显著差异(P>0.05),另两实验组与对照组比较,差异具有显著统计学意义(P<0.01)。与此同时,各组大鼠胃液EGF含量:重复暴露组<+10Gz暴露组<+5Gz暴露组<对照组。+5Gz暴露组与对照组相比胃液EGF含量无显著差异(P>0.05),另两实验组与对照组比较,具有显著性差异(P<0.01)。结论大鼠在越高水平+Gz值暴露下,胃黏膜受损程度越重,胃液EGF含量越低。高+Gz值暴露造成的急性胃黏膜病变与胃黏膜的保护因子EGF表达下降有关。

Objective To investigate the effects of different ＋ Gz exposure on the gastric mucosal lesions and the changes of EGF level in the gastric juice of the rats. Methods 40 male wistar rats were divided into 4 groups： ① control group （ n = 10） ： without ＋ Gz exposure ; ② ＋ 5 Gz group （n = 10） ： undergone ＋ 5 Gz exposure for 5 min ; ③ ＋ 10 Gz group （n = 10） ： undergone ＋ 10 Gz exposure for 5 rain; ④ Repeat group （n = 10） ： undergone ＋ 5 Gz exposure for 1.5 min, and ＋ 10 Gz exposure for 2 min, and then ＋ 5 Gz exposure for 1.5 min again. The rats were killed after centrifugated. Gastric mucosa samples were collected. First, the changes of gastric mucosa were observed by light microscope, and the damage index of the gastric mucosa was measured by vernier calipers. Then, the levels of epidermal growth factor （EGF） in gastric juice were determined by the method of radioimmunoassay （RIA）. Results Severe de- gree of gastric mucosal lesions in the 4 groups were Repeat group 〉 ＋ 10 Gz group 〉 ＋5 Gz group 〉 control group. There was no difference in the gastric mucosal damage index between the ＋ 5 Gz group and the control group （P 〉 0.05） , and that in the other two experiment groups was signifficantly different （P 〈 0. 01 ）. Meanwhile, EGF levels in the gastric juice of the 4 groups were repeat group 〈 ＋ 10 Gz group 〈 ＋ 5 Gz group 〈 control group. There was no difference in the EGF level in the gastric juice between the ＋ 5 Gz group and the control group （P 〉0. 05） , and that in the other two experiment groups was signifficant （P 〈 0.01 ）. Conclusion Higher ＋ Gz exposure may result in the greater gastric muco- sal lesions. This mechanism is related to the lower expression of EGF in the gastric juice.