脐血间充质干细胞移植修复急性肠缺血再灌注损伤

Umbilical cord blood mesenchymal stem cell transplantation for acute intestinal ischemia-reperfusion injury

背景:研究表明,骨髓间充质干细胞对肠缺血/再灌注有一定的修复作用,其机制为干预肠缺血/再灌注后的炎性反应从而对肠道屏障功能的完整性起到保护作用。近年来脐血间充质干细胞逐渐成为骨髓间充质干细胞很好的替代来源。目的:探讨脐血间充质干细胞移植对大鼠急性肠缺血再灌注损伤的修复作用。方法:体外诱导分离脐血间充质干细胞,观察CM-Di I荧光标记后脐血间充质干细胞的去向。63只SD大鼠随机分为3组,每组20只。缺血/再灌注损伤组及脐血间充质干细胞移植组采用TNBS(乙醇稀释)灌肠制备肠缺血/再灌注损伤模型;脐血间充质干细胞移植组在TNBS建模后1 h,于尾静脉输入1×1010 L-1脐血间充质干细胞悬液;对照组仅采用生理盐水灌肠。移植后3 d,分别于各组大鼠取结肠组织行苏木精-伊红染色,观察肠道的病理变化;RT-PCR法检测结肠组织中leptin m RNA的表达;利用免疫组化法检测肠黏膜中环氧化酶2表达。结果与结论:1荧光示踪结果显示,移植的脐血间充质干细胞分布于肠黏膜淋巴组织内和腺上皮细胞间,表明脐血间充质干细胞可能参与了肠缺血再灌注损伤的修复过程;2苏木精-伊红染色观察到与对照组相比,缺血/再灌注损伤组肠道损伤明显加重,肠黏膜上皮细胞脱落较多,脐血间充质干细胞移植组肠道损伤明显减轻,细胞脱落也明显见少;leptin m RNA在缺血/再灌注损伤组呈现高表达,其表达量明显大于对照组及脐血间充质干细胞移植组,脐血间充质干细胞移植组又明显大于对照组,各组间比较,差异有显著性意义(P<0.05);3免疫组化结果显示,缺血/再灌注损伤组肠黏膜环氧化酶2表达明显高于对照组(P<0.05),脐血间充质干细胞移植组环氧化酶2表达明显低于缺血/再灌注损伤组(P<0.05);4提示leptin及环氧化酶2可能参与了大鼠急性肠缺血再灌注损伤的发生过程,脐血间充质干细胞移植干预后明显减轻了大鼠肠缺血再灌注的损伤程度,为人类急性肠缺血损伤的治疗提供了实验依据。

BACKGROUND： Bone marrow mesenchymal stem cells can repair intestinal ischemia-reperfusion injuny by interfering inflammatory reactions after intestinal ischemia-reperfusion to protect intestinal barrier functions. In recent years, umbilical cord blood mesenchymal stem cells are gradually used as a substitute source of bone marrow mesenchymal stem cells. OBJECTIVE： To investigate the effects of umbilical cord blood mesenchymal stem cells on acute intestinal ischemia-reperfusion injury. METHODS： Umbilical cord blood mesenchymal stem cells were induced, isolated in vitro and tracked by CM-Di I fluorescent labeling. Sixty-three Sprague-Dawley rats were equivalently randomized into three groups： control group received normal saline enema, intestinal ischemia-reperfusion injury group with ethanol diluted trinitro-benzene-sulfonic acid and transplantation group administrated with 1×1010/L umbilical cord blood mesenchymal stem cell suspension via the tail vein at 1 hour after trinitro-benzene-sulfonic acid modeling. At 3 days after transplantation, colon tissues were removed in each group to observe pathological changes of the intestinal tract by hematoxylin-eosin staining. Besides, expression of leptin mRNA in the colon tissues and cyclooxygenase-2 in the mucosa were detected by RT-PCR and immunohistochemistry method, respectively. RESULTS AND CONCLUSION： Transplanted umbilical cord blood mesenchymal stem cells distributed in the intestinal lymphoid tissue and among glandular epithelial cells, suggesting that these stem cells might be involved in the process of intestinal ischemia-reperfusion injury repair. Compared with the control group, intestinal injury in the injury group was significantly aggravated, and most intestinal epithelial cells shed; and the transplantation group appeared to have significantly reduced intestinal damage and significantly less cell shedding. Expression of leptin mRNA was significantly higher in the injury group than the transplantation group followed by the control group, and there were significant differences among the three groups（P〈0.05）. Additionally, expression of cyclooxygenase-2 in the injury group was significantly higher than that in the control group（P〈0.05）; compared with the injury group, expression of cyclooxygenase-2 was significantly lower in the transplantation group（P〈0.05）. To conclude, leptin and cyclooxygenase-2 may be involved in acute intestinal ischemia-reperfusion injury, and umbilical cord blood mesenchymal stem cell transplantation significantly lessens intestinal ischemia-reperfusion injury, which provides an experimental basis for human treating acute intestinal ischemic injury.