他克莫司对小鼠肠黏膜屏障功能的损伤作用及分子机制

摘要

Objective To observe the damaging effect of tacrolimus (FK506) on intestinal mucosal barrier function in mice and to investigate its possible molecular mechanisms.Methods Twenty-four C57BL/6 mice were randomly divided into 3 groups (8 in each group):high-dose group (5 mg/kg), low-dose group (1 mg/kg) and the control group (normal saline).All mice were sacrificed after FK506 was administered for 30 days and the intestinal mucosal tissues were obtained .The structure of intestinal mucosa was observed by HE staining and ultrastructure was observed by transmission electron microscope .The level of D-lactate was detected by spectrophotometry .The function of mitochondrion was detected with Clark electrodes .The adenosine triphosphate (ATP) was detected with high pressure liquid chromatography.Results The body weight of mice was decreased significantly in the high-dose and low-dose groups as compared with that of the control group , and the body weight lost more in the high-dose group than in the low-dose group (all P<0.05).The ultrastructure of intestinal mucosa was destroyed in high-dose and low-dose groups and it showed a dose-dependent manner.Compared with the control group, the level of D-lactate was in-creased significantly in the high-dose and low-dose groups and it was more significant in the high-dose group (all P<0.05). Compared with the control group, stateⅢoxygen consumption, respiratory control ratio, membrane potential and enzymatic activ-ity of ATP were decreased significantly and stateⅣoxygen consumption was increased significantly in the high-dose and low-dose groups, and the changes were more significant in the high-dose group than in the low-dose group (all P<0.05).Conclusion FK506 could destroy the intestinal mucosal barrier function with a dose-dependent manner, and the molecular mechanism may be caused by destruction of the mitochondrion of intestinal mucosal cells .%目的 观察他克莫司( FK506 )对小鼠肠黏膜屏障功能的损伤作用,并探讨其分子机制. 方法 将24只C57 BL/6小鼠随机分为高剂量组、低剂量组和对照组各8只,分别予FK506 5 mg/kg、FK506 1 mg/kg、生理盐水灌胃. 用药30 d处死小鼠,收集肠黏膜组织标本,采用HE染色法观察肠黏膜组织结构变化,透射电镜下观察肠黏膜上皮细胞紧密连接的超微结构改变,采用分光光度法测定血浆D-乳酸,氧电极法测定肠组织线粒体呼吸功能,高压液相色谱法检测肠黏膜上皮细胞线粒体三磷酸腺苷( ATP)酶活性. 结果 低、高剂量组小鼠体质量较对照组明显减轻,高剂量组减轻更明显(P均<0.05);低、高剂量组小鼠肠上皮细胞间紧密连接超微结构遭到破坏,其损伤程度与FK506剂量呈正相关;与对照组比较,低、高剂量组小鼠血浆D-乳酸水平升高,高剂量组升高更明显( P均<0.05);与对照组比较,低、高剂量组小鼠小肠3态呼吸耗氧量、呼吸控制率、膜电位、ATP酶活性下降,4态呼吸耗氧量升高,高剂量组变化更明显(P均<0.05). 结论 FK506能损伤小鼠肠黏膜屏障功能,且损伤程度呈剂量依赖性;其分子机制可能是通过损伤小鼠肠黏膜细胞线粒体功能而损伤肠黏膜屏障功能.