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目的研究尾悬吊模拟失重对大鼠胃窦肌层诱生型环氧化酶2(Cox-2)表达和血清生长抑素(SS)、血管活性肠肽(VIP)水平的影响。方法健康雄性Wistar大鼠64只,随机分为8组,按模拟失重时相分为0h(对照组)和6h、12h、1d、2d、3d、5d、7d组(n=8)。采用尾悬吊法建立模拟失重动物模型。应用RT-PCR、Western blotting和免疫组化技术检测各组大鼠胃窦肌层组织中Cox-2 mRNA和蛋白表达情况,应用放免法测定血清SS、VIP浓度。结果免疫组化结果显示,Cox-2蛋白阳性表达为棕褐色,悬吊6h、12h、1d大鼠胃窦平滑肌细胞胞质染色变深并出现部分核染色阳性,2d开始逐渐恢复,但胞质着色仍较对照组深。RT-PCR结果显示,Cox-2 mRNA表达水平在尾悬吊6h即出现显著增高,12h、1d时仍呈高水平表达(P<0.05),2d后表达水平逐渐回落(P>0.05)。Western blotting结果显示,悬吊6h大鼠胃窦肌层Cox-2蛋白表达水平显著升高,12h、1d持续高表达,与对照组比较差异有统计学意义(P<0.05),2d后逐渐恢复正常水平(P>0.05)。血清SS浓度在尾悬吊模拟失重2~3d达峰值,与对照组比较差异有统计学意义(P<0.05),其他各时相浓度值波动明显。血清VIP浓度同样在模拟失重早期即显著升高(P<0.05),峰值出现在6~12h,其后经过2~3d的回落后复又升高。结论胃窦肌层Cox-2表达异常和血清SS及VIP水平变化在胃窦失重应激性动力障碍及恢复过程中可能发挥重要作用。
Objective To investigate the effect of simulated weightlessness of tail suspension on the expression of Cox-2 and the levels of somatostatin (SS) and vasoactive intestinal peptide (VIP) in rat gastric antral muscle. Methods Sixty-four healthy male Wistar rats were randomly divided into 8 groups. The rats were divided into 0h (control group) and 6h, 12h, 1d, 2d, 3d, 5d and 7d groups according to simulated weightlessness (n = 8). Animal models of simulated weightlessness were established by tail suspension method. The expression of Cox-2 mRNA and protein in gastric antral muscle of rats in each group were detected by RT-PCR, Western blotting and immunohistochemistry. Serum SS and VIP levels were determined by radioimmunoassay. Results Immunohistochemical results showed that the positive expression of Cox-2 protein was tan, and the cytoplasmic staining of gastric antral smooth muscle cells became darker at 6h, 12h and 1d after the suspension, and some of the nuclear staining appeared positive, gradually recovered from 2d, but the cytoplasm Coloring is still deeper than the control group. The results of RT-PCR showed that the expression of Cox-2 mRNA was significantly increased 6 h after the tail suspension and remained high at 12 h and 1 d (P <0.05), and gradually decreased after 2 d (P> 0.05). The results of Western blotting showed that the expression of Cox-2 protein in gastric antral muscle was significantly increased 6 h after suspension, and remained high at 12 h and 1 d (P <0.05), and gradually recovered after 2 days Normal level (P> 0.05). Serum SS concentration peaked at 2-3 days after simulated weightlessness in tail suspension, which was significantly different from that in control group (P <0.05). Other concentrations in other phases fluctuated significantly. Serum VIP concentration also increased significantly in the early stage of simulated weight loss (P <0.05), the peak appeared in 6 ~ 12h, then after 2 ~ 3d down and then increased again. Conclusion The abnormal expression of Cox-2 in gastric antral muscle and the changes of serum SS and VIP levels may play an important role in the process of dysfunction and recovery of gastric antrum.