利用扩散加权成像评估MitoQ对大鼠肾脏缺血再灌注损伤的保护作用

目的探讨扩散加权成像(diffusion weighted imaging,DWI)表观扩散系数(apparent diffusion coefficient,ADC)评估线粒体靶向抗氧化剂Mito Q对大鼠肾脏缺血再灌注损伤(ischemia-reperfusion injury,IRI)保护作用的可行性。材料与方法暂时夹闭大鼠左侧肾动脉45 min以建立IRI模型。10只雄性SD大鼠随机分为Mito Q组(5只,IRI+Mito Q)和对照组(5只,IRI+生理盐水)。在术前(第0天)和术后不同时间(第2、5、7和14天)对大鼠进行DWI扫描,并测量双侧肾外髓外带(the outer stripe of the outer medulla,OSOM)的ADC值。最后一次MRI检查结束后对肾脏组织病理学损伤程度进行评分。采用最小显著差法比较不同时间点组间及组内ADC值的差异。借助Kruskal-Wallis H检验和Mann-Whitney U检验比较不同肾脏组织病理学评分之间的差异。结果术前两组大鼠双肾ADC值无明显差异。术后两组大鼠右肾ADC值无明显差异,在术后各时间点,每组大鼠左肾OSOM的ADC值均低于右肾(P0.01),对照组左肾ADC值于各时间点均低于Mito Q组。第2天Mito Q组和对照组左肾分别为(3.66±0.29)×10-4 mm2/s、(3.09±0.39)×10-4 mm2/s,P0.05;第5天Mito Q组和对照组左肾分别为(3.75±0.32)×10-4 mm2/s、(2.95±0.79)×10-4 mm2/s,P0.05;第7天Mito Q组和对照组左肾分别为(3.77±0.42)×10-4 mm2/s、(2.98±0.49)×10-4 mm2/s,P0.05;第14天Mito Q组和对照组左肾分别为(3.93±0.23)×10-4 mm2/s、(3.05±0.20)×10-4 mm2/s,P0.05。肾脏组织病理学分析表明肾损伤最严重的区域发生在对照组IRI肾脏OSOM,其组织病理学损伤评分高于Mito Q组IRI肾脏(P0.01)。结论肾脏扩散加权成像可无创评价Mito Q减轻大鼠肾脏缺血再灌注损伤的作用。

MitoQ protects rodent kidneys from ischemia-reperfusion injury: observations with DWI

Objective: To investigate the effect of the mitochondria targeted antioxidant MitoQ in protecting from renal ischemia-reperfusion injury (IRI) in rats by longitudinal observation on apparent diffusion coefficient (ADC) values of the kidney measured with diffusion-weighted imaging (DWI). Materials and Methods: Renal IRI was induced by temporarily clamping the left renal artery for 45 minutes and then reperfusion was realized. Ten male Sprague–Dawley rats were randomly divided into two groups: MitoQ group (n=5, IRI+MitoQ) and control group (n=5, IRI+saline). DWI was performed just before the operation (day 0) and on day 2, 5, 7 and 14 after the operation. ADC value of the outer stripe of the outer medulla (OSOM) was measured on bilateral kidneys. Renal histopathology damage score was evaluated after the final MRI examination. Inter- and intra- group differences were assessed using the Least Significant Difference (LSD). Kruskal-Wallis H test and Mann-Whitney U test were used for histopathology damage score analysis. Results: The ADC values of the kidneys in two groups on day 0 had no statistical significance. The ADC values of the left OSOM dropped dramatically after IRI in both of the groups, and it was more obvious in control group. The ADC values of the OSOM on IRI kidneys were lower than their counterparts (P<0.01), and the ADC values of the OSOM in control group were even lower than that in MitoQ group Day 2, the left OSOM on MitoQ group and control group: (3.66±0.29)×10-4 mm2/s. (3.09±0.39)×10-4 mm2/s, P<0.05. Day 5, the left OSOM on MitoQ group and control group: (3.75±0.32)×10-4 mm2/s, (2.95±0.79)×10-4 mm2/s, P<0.05. Day 7, the left OSOM on MitoQ group and control group: (3.77±0.42)×10-4 mm2/s, (2.98±0.49)×10-4 mm2/s, P<0.05, Day 14, the left OSOM on MitoQ group and control group: (3.93±0.23)×10-4 mm2/s, (3.05±0.20)×10-4 mm2/s, P<0.05. Renal histopathology analysis showed that renal damage was the most predominant on the OSOM of IRI kidneys in control group, whose histopathology damage scores were significantly higher than those in MitoQ group (P<0.01). Conclusions: DWI could be a noninvasive method to evaluate the effect of MitoQ on reducing renal IRI in rats.