Th17细胞相关细胞因子在大鼠小肠移植急性排斥反应中的作用

Effects of Th17-related cytokines in acute rejection in rat small bowel transplantation

目的通过对大鼠小肠移植FK506预处理模型研究,探讨Th17细胞相关细胞因子在大鼠小肠移植急性排斥反应中的表达。根据病理表现及相关细胞因子表达,进一步探究Th17细胞相关因子在大鼠小肠移植急性排斥的作用机理,试图为预防小肠移植急性排斥损伤提出新思路。方法雄性健康F344大鼠5对及Lewis大鼠10对,6～8周龄,采用数字表法随机分为对照1组(F344 5只、Lewis 5只)、对照2组(Lewis大鼠5对)和实验组(F344 5只、Lewis 5只)。采用供体肠系膜上动脉-受体腹主动脉端侧、供体门静脉-受体下腔静脉端侧吻合法,供体肠管近端旷置远端回肠-回肠端侧吻合的异体全段性小肠移植术式。实验组:FK506按2 mg/Kg的剂量实验前3日每日肌肉注射,手术当日及术后7 d,按0.3 mg.kg-1.d-1肌肉注射。术后7 d处死受体大鼠或濒死大鼠,取供体肠管行HE染色及免疫组织化学染色观察病理变化,右心室穿刺取血用ELISA方法检测血清中IL-17、IL-23、IL-6、TGF-β、IFN-γ的含量。结果在大鼠小肠移植急性排斥反应模型中,移植肠管的黏膜发生明显的病理形态学改变。对照1组小肠黏膜的病理形态学改变最明显,实验组病理学改变相对较轻,对照2组大鼠小肠黏膜改变最轻。免疫组织化学染色提示巨噬细胞浸润以对照1组最明显,其次为实验组,对照2组浸润最轻。实验组和对照组的大鼠静脉血血清中的IL-6、IL-17、IL-23、TGF-β平均浓度大体趋势相同,各种细胞因子以对照1组最高,实验组次之,对照2组最低。结论在大鼠小肠移植模型中,FK506预处理能减轻小肠移植急性排斥反应造成的黏膜损伤,有利于移植受体的存活。其机理与减少移植肠管巨噬细胞的浸润有关。对照1组和实验组大鼠血液中IL-17、IL-23等细胞因子水平均值都高于对照2组,提示Th17相关因子参与急性排斥反应过程。阻断Th17相关因子产生可能会减轻小肠移植急性排斥反应损伤。

Objective Through using FK506 pre-treatment model in acute rejection of rat small bowel transplantation （SBT）, the pathological change and the expressions of Thl7-related cytokines were investigated. This study aimed to analyze the effects of Thl7-related cytokincs in acute rejection in SBT, and to find a new strategy for preventing acute rejection in SBT. Methods Twenty healthy male F344 and Lewis rats, 6 -8 weeks old, were randomly divided into three groups： allograft control group （Lewis 5 pairs）, allogeneic control group （F344, 5; Lewis, 5） and FK506 pre-treatment group （FM4, 5; Lewis, 5）. For FKS06 pre-treatment group： FKS06 was daily injected intramuscularly with 2 mg/Kg dose for 3 days before operation, and the dose was adjusted to 0.3 mg·kg^-1·d^-1 postoperatively. The recipients were sacrificed on 7 day postoperatively or before dying. The intestinal samples were obtained for pathological and immunohistochemical analyses. The blood was taken from right ventricular puncture for the detection of the concentration of IL-17, IL-23, IL-6, TGF-beta, and IFN-γ by ELISA. Results The transplanted bowel mucosa has significant pathological changes in acute rejection of small bowel transplantation. The control group 1 showed the most significant changes in pathological morphology, pathological changes in experimental group were relatively mild, the control group 2 showed mildest. The immtmohistochemieal staining suggested that the infiltration of macrophages was the most obvious in the control group 1, followed by the experimental group, and the control group 2 showed the mildest. The IL-6, IL-17, IL-23 and TGF-beta levels in the experimental and control groups had the same trend; all of them in control group 1 were the highest. Conclusion The pathological findings suggested that pretreatment FK506 could reduce the mucosal injury caused by acute rejection in SBT which may be related to the reduced infiltration of macrophages in transplanted intestine. In control group 1 and experimental group, IL-17 and IL-23 cytokine levels were higher than those of the control group 2, suggesting that these cytokines may be involved in acute rejection in SBT. The blockade of Thl7-related cytokines may be beneficial to alleviate acute rejection in SBT.