Department of Geriatrics, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China.
Department of Nephrology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China.
Mol Med Rep. 2017 Oct;16(4):3817-3824. doi: 10.3892/mmr.2017.7096. Epub 2017 Jul 27.
It has been previously demonstrated that 1,25(OH)2D3 prevents the progression of epithelial to mesenchymal transition (EMT). However, it remains unclear whether 1,25(OH)2D3 has a role in peritoneal EMT stimulated by high glucose (HG) peritoneal dialysis fluid (PDF). The present study was performed to investigate the role of 1,25(OH)2D3 in the progression of EMT in the peritoneal mesothelium. A total of 35 male Kunming mice were randomly assigned into seven groups. In the control group, no diasylate or saline was infused. In the saline group, the mice were intraperitoneally injected with saline every day for 4 weeks. In the vitamin D group, the mice were subjected to intraperitoneal injections of 1 or 5 µg/kg of 1,25(OH)2D3 once weekly (every Monday) for 4 weeks. The peritoneal dialysis (PD) group were intraperitoneally injected with a conventional 4.25% PDF daily for 4 weeks. The vitamin D+PD group were intraperitoneally injected with 4.25% PDF daily and co‑treated with 1 µg/kg or 5 µg/kg 1,25(OH)2D3 once weekly, for 4 weeks. The peritoneal morphology and thickness were assessed by hematoxylin and eosin and Masson's trichrome staining. The peritoneal protein level of EMT markers (α‑smooth muscle actin, fibronectin and E‑cadherin), vitamin D receptor (VDR), B cell lymphoma‑2 (Bcl‑2), Bcl‑2‑associated X protein, transforming growth factor (TGF)‑β and Smad3 were evaluated by western blot analysis or immunohistochemical staining. Furthermore, apoptosis was assessed using a Caspase‑3 activity assay. The results demonstrated that after 4 weeks of intraperitoneal injections in mice, HG‑PDF decreased the expression of VDR, promoted EMT and apoptosis, and increased the thickness of the peritoneal membrane. However, 1,25(OH)2D3 treatment attenuated HG‑induced EMT and apoptosis, and decreased peritoneal thickness, which may partially occur through inhibition of transforming growth factor TGF‑β/Smad pathways via 1,25(OH)2D3 binding to VDR. The present study demonstrated that 1,25(OH)2D3 attenuated HG‑induced EMT and apoptosis in the peritoneal mesothelium through TGF‑β/Smad pathways. 1,25(OH)2D3 treatment in conjunction with HG dialysate may provide an improved solution to the peritoneal injury in the process of PD.
先前的研究已经证实 1,25(OH)2D3 可以阻止上皮细胞向间充质转化（EMT）的进展。然而，目前尚不清楚 1,25(OH)2D3 是否在高糖（HG）腹膜透析液（PDF）刺激的腹膜 EMT 中发挥作用。本研究旨在探讨 1,25(OH)2D3 在腹膜间皮 EMT 进展中的作用。共 35 只雄性昆明小鼠随机分为七组。在对照组中，不给予二膦酸盐或生理盐水。在生理盐水组中，每天给小鼠腹膜内注射生理盐水，持续 4 周。在维生素 D 组中，每周一（每周一）给小鼠腹膜内注射 1 或 5μg/kg 的 1,25(OH)2D3，持续 4 周。腹膜透析（PD）组每天腹膜内注射常规 4.25% PDF，持续 4 周。维生素 D+PD 组每天腹膜内注射 4.25% PDF，并每周一次同时给予 1μg/kg 或 5μg/kg 的 1,25(OH)2D3，持续 4 周。通过苏木精和伊红以及 Masson 三色染色评估腹膜形态和厚度。通过 Western blot 分析或免疫组织化学染色评估 EMT 标志物（α-平滑肌肌动蛋白、纤维连接蛋白和 E-钙粘蛋白）、维生素 D 受体（VDR）、B 细胞淋巴瘤-2（Bcl-2）、Bcl-2 相关 X 蛋白、转化生长因子（TGF）-β和 Smad3 的腹膜蛋白水平。此外，通过 Caspase-3 活性测定评估细胞凋亡。结果表明，在小鼠腹膜内注射 4 周后，HG-PDF 降低了 VDR 的表达，促进了 EMT 和细胞凋亡，并增加了腹膜的厚度。然而，1,25(OH)2D3 治疗减轻了 HG 诱导的 EMT 和细胞凋亡，并减少了腹膜厚度，这可能部分通过 1,25(OH)2D3 与 VDR 结合抑制 TGF-β/Smad 途径来实现。本研究表明，1,25(OH)2D3 通过 TGF-β/Smad 途径减轻 HG 诱导的腹膜间皮 EMT 和细胞凋亡。1,25(OH)2D3 联合 HG 透析液治疗可能为 PD 过程中的腹膜损伤提供更好的解决方案。
