Department of Nephro-urology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan.
Urolithiasis. 2018 Nov;46(6):515-522. doi: 10.1007/s00240-018-1040-3. Epub 2018 Jan 23.
We previously established an experimental model of calcium oxalate crystal deposition in the mouse kidney using C57BL/6 mice. C57BL/6J (B6J) and C57BL/6N (B6N) are two core substrains of C57BL/6 mice. B6J and B6N substrains have approximately the same genomic sequence. However, in whole-genome analyses, substrains have slight genetic differences in some genes. In this study, we used these substrains as kidney crystal formation models and compared their genetic backgrounds to elucidate the pathogenic mechanisms of kidney stone formation. Eight-week-old male B6J and B6N mice (n = 15 in each group) were administered 80 mg/kg glyoxylate for 12 days, and the amount of kidney crystal depositions was compared. The expression levels of six genes (Snap29, Fgf14, Aplp2, Lims1, Naaladl2, and Nnt) were investigated by quantitative polymerase chain reaction, and the protein levels were evaluated by western blotting and immunohistochemistry. The amount of kidney crystal depositions was significantly higher in B6J mice than in B6N mice on days 6 and 12. The expression of nicotinamide nucleotide transhydrogenase (Nnt) gene was significantly lower in B6J mice than in B6N mice. The expression of Nnt protein was observed only in B6N mice, and preferential high expression was seen in renal tubular epithelial cells. The results of this study provide compelling evidence that differences in mouse substrains affect kidney crystal deposition and that the absence of Nnt protein could be involved in crystal formation in B6J mice.
我们之前使用 C57BL/6 小鼠建立了草酸钙晶体在小鼠肾脏沉积的实验模型。C57BL/6J（B6J）和 C57BL/6N（B6N）是 C57BL/6 小鼠的两个核心亚系。B6J 和 B6N 亚系的基因组序列大致相同。然而，在全基因组分析中，亚系在一些基因上存在轻微的遗传差异。在这项研究中，我们使用这些亚系作为肾脏晶体形成模型，并比较它们的遗传背景，以阐明肾结石形成的发病机制。将 8 周龄雄性 B6J 和 B6N 小鼠（每组 15 只）给予 80mg/kg 乙醛酸 12 天，并比较肾脏晶体沉积量。通过定量聚合酶链反应研究了六个基因（Snap29、Fgf14、Aplp2、Lims1、Naaladl2 和 Nnt）的表达水平，并通过 Western 印迹和免疫组织化学评估了其蛋白水平。在第 6 天和第 12 天，B6J 小鼠肾脏晶体沉积量明显高于 B6N 小鼠。B6J 小鼠中烟酰胺核苷酸转氢酶（Nnt）基因的表达明显低于 B6N 小鼠。Nnt 蛋白仅在 B6N 小鼠中观察到，且在肾小管上皮细胞中呈优先高表达。这项研究的结果提供了有力的证据表明，小鼠亚系的差异会影响肾脏晶体沉积，并且 Nnt 蛋白的缺失可能参与了 B6J 小鼠晶体的形成。
