环氧化酶-2在小肠缺血再灌注损伤中的作用研究

Effect of cyclooxygenase-2 on injury to intestine induced by ischemia reperfusion in rat

目的探讨环氧化酶-2(COX-2)在小肠缺血再灌注(I/R)损伤中对前列腺素I2(PGI2)/血栓素A2(TXA2)系统的影响。方法48只雄性SD大鼠随机分为3组:对照组(n=8)、I/R组(n=20)和干预组(n=20),I/R组大鼠麻醉后,取腹正中切口,钝性游离肠系膜上动脉,将其根部夹闭阻断血流45min,然后恢复血流灌注,建立大鼠小肠I/R模型。干预组术前1h用Nimeshulide灌胃,其余步骤同I/R组。手术后3、6、12、24h取血和小肠组织标本检测。酶联紫外分光光度法测定血浆D-乳酸水平;放射免疫法检测PGI2和TXA2的稳定代谢产物6-酮-前列腺素1α(6-keto-PGF1α)和血栓素B2(TXB2)在血清及小肠组织中的表达;RT-PCR检测COX-2mRNA表达。结果与对照组比较,I/R组小肠COX-2表达明显增加,血浆D-乳酸、6-keto-PGF1α、TXB2水平均升高,以TXB2升高明显,6-keto-PGF1α/TXB2比值降低(P<0.05);与I/R组比较,干预组小肠COX-2表达明显减少,血浆D-乳酸、6-keto-PGF1α、TXB2水平均明显降低,以TXB2降低较明显,6-keto-PGF1α/TXB2比值升高(P<0.05)。结论COX-2可通过影响PGI2/TXA2的失衡加重小肠I/R损伤。

Objective To investigate the effect of eyelooxygenase-2 （cox-2） on prostaglandin 12 （PGI2）/thromboxane A2 （TXA2） system in ischemia reperfusion （I/R） injury to small bowel in rat. Methods Forty-eight male SD rats were randomly divided into three groups： control group （n=8）, UR group （n 20） and intervention group （n=20）. Small intestine UR model was established with the animals of I/R group： after anesthesia, rats were split along the middle abdominal incision, the mesenteric artery was then bluntly separated and clipped with a blood vessel forceps at its root for 45 minutes to block the blood flow, then releasing the forceps for reperfusion. Animals of intervention group were lavaged with Nimeshulide 1h before operation, the remaining steps were the same as did in I/R group. The samples of blood and intestinal tissue were collected at 3, 6, 12 and 24 hours after operation. The content of plasma Dlactate was detected by ultraviolet spectrophotometric method. Radioimmunoassay was used to detect 6-ketO-PGF1α （the stable metabolite of PGI2, reflected the level of PGI2） and thromboxane B2 （TXB2, stable metabolite of TXA2, reflected the level of TXA2） in serum and tissues of small bowel. The expression of cox-2 mRNA was detected by RT-PCR. Results Compared with the control group, the levels of plasma D-lactate, cox-2, 6 keto-PGF1α and TXB2 were significantly increased in I/R group, with more obvious increase of TXB2, and the value of 6-keto-PGF1α/TXB2 decreased significantly （P〈0. 05）. Compared with I/R group, the levels of plasma Dlaetate, cox-2, 6-keto- PGF1 α and TXB2 were significantly decreased in intervention group, with more obvious decrease of TXB2, and the value of 6-keto-PGF1α/ TXB2 increased significantly （P〈0.05）. Conclusion Cyclooxygenase-2 may exacerbate I/R induced bowel injury by throwing an influence on the imbalance of PGI2/TXA2 system.