Evaluation of the three dimendional microvascular structure and physiological function of renal glomerulus using superphoton derived X-ray micro focus CT

我们的目标是使用超光子衍生的X射线微焦点CT(MCT)显示三维(3D)肾小球微结构，以准确测量整个皮质的肾小球体积，并定量评估自发性糖尿病(DM)大鼠肾小球体积分布的全局异质性。以OLETF大鼠为早期糖尿病大鼠(28周，n=5)和同龄对照大鼠(Long Evans Tokushima Fatty，LETO，n=5)，左肾血管充盈造影剂(BaSO4+印度墨水+8%明胶)。使用两个MCT系统观察采样的肾柱(3-4 mm)：8GeV-SuperPhoton MCT用于最高图像质量(3-6 mm分辨率)和商用MCT(10 mm分辨率)用于数据积累。用变异系数(CV)计算肾小球体积大于400个/样本。通过体视显微镜观察，我们证实造影剂已完全填充血管。OLETF组肾小球立体结构不规则，而LETO组肾小球结构规则。OLETF组肾小球体积变异系数显著大于LETO组(P&lt；0.01)。此外，OLETF组的肾小球绝对体积大于LETO组(P&lt；0.005)。然而，标准化的肾小球体积是可比的(NS)，这表明早期糖尿病的肾小球增大可能与体质量的增加有关。两种MCT都提供了类似的结果。用我们开发的三维肾小球微结构可视化方法定量显示了糖尿病大鼠肾小球高度不均匀的体积分布。这项技术为评估慢性肾功能不全下肾小球重构的全球异质性提供了一个新的角度，可能为糖尿病肾病的早期并发症提供更敏感的洞察。

We aimed at visualizing thee dimensional (3D) glomerular micro- structures using a superphoton derived X- ray micro focus CT (Mct) to accurately measure glomerular volumes throughout a cortex and quantitatively evakuate global heterogeneity of the volume- distribution in a rat with spontaneous diabetes mellitus (DM). Using the Otsuka Long Evans Tokushima Fatty (OLETF) rats as rats of early stage DM (28 weeks, n=5) and control rats (Long Evans Tokushima Fatty; LETO, n=5) of the same age, the vessels of the left kidney was filled up with contrast media (BaSO_4 + India ink + 8%gelatin). A sampled renal column (3-4 mm) was observed using two Mct system; 8GeV- superphoton Mct for the highest image quality (3-6 mm in resolution) and commercially available Mct (10 mm in resolution) for data accumulation. The glomerular volumes more than 400 per sample were computed by coefficient variation (CV). By stereomicroscopic observation, we confirmed complete- filling of the vessels with the contrast media. The glomeruli in OLETF were characterized by irregular stereostractures, whereas those in LETO were characterized by regular glomerular structure. The CV of glomerular volume was significantly larger in OLETF than LETO (p<0.01). In addition, absolute glomerular volume was larger in OLETF than LETO (p<0.005). The normalized glomerular volume was, however, comparable (NS), indicating glomerular enlargement in early DM may associate with increase in body mass. Both Mct provided similar results. Highly heterogeneous glomerular volume- distribution in DM rat was quantitatively demonstrated using our developed 3D glomerular micro- structural visualizing method. This technique provides a new aspect for the evaluation of global heterogeneity in glomerular remodeling under the chronic renal dysfunction, which may provide more sensitive insight into early complications of diabetic nephropathy