Henan Academy of Chinese Medicine, Zhengzhou, 450000, China.
Henan University of Chinese Medicine, Zhengzhou, 450000, China.
J Physiol Biochem. 2020 Aug;76(3):407-416. doi: 10.1007/s13105-020-00747-z. Epub 2020 Jun 4.
Renal fibrosis is a major pathological event in the development of diabetic nephropathy (DN). Baicalin is a flavonoid glycoside that possesses multiple pharmacological properties including anti-fibrotic activity. In the present study, the effects of baicalin on renal fibrosis along with related molecular basis were investigated in streptozotocin (STZ)-induced DN mouse model and high glucose (HG)-treated HK-2 human proximal tubule epithelial cell model. Renal injury was evaluated through blood urea nitrogen (BUN) and serum creatinine (Scr) levels and urine albumin creatine ratio (ACR). Renal fibrosis was assessed by type IV collagen (COLIV) and fibronectin (FN) protein expression and histopathologic analysis via Masson trichrome staining. Protein levels of COLIV, FN, NF-κB inhibitor alpha (IκBα), phosphorylated IκBα (p-IκBα), p65, phosphorylated p65 (p-p65), and toll-like receptor 4 (TLR4) were measured by western blot assay. MicroRNA-124 (miR-124) and TLR4 mRNA levels were detected by RT-qPCR assay. The interaction of miR-124 and TLR4 was examined by bioinformatics analysis, luciferase reporter assay, and RIP assay. Baicalin or miR-124 attenuated renal injury and fibrosis in STZ-induced DN mice. Baicalin inhibited the increase of COLIV and FN expression induced by HG through upregulating miR-124 in HK-2 cells. TLR4 was a target of miR-124. MiR-124 inhibited TLR4/NF-κB pathway activation and the inactivation of the NF-κB pathway hindered COLIV and FN expression in HG-stimulated HK-2 cells. Baicalin prevented renal fibrosis by increasing miR-124 and inactivating downstream TLR4/NF-κB pathway in DN, hinting the pivotal values of baicalin and miR-124 in the management of DN and renal fibrosis.
肾纤维化是糖尿病肾病（DN）发展过程中的主要病理事件。黄芩苷是一种黄酮类糖苷，具有多种药理作用，包括抗纤维化活性。在本研究中，研究了黄芩苷在链脲佐菌素（STZ）诱导的 DN 小鼠模型和高糖（HG）处理的 HK-2 人近端肾小管上皮细胞模型中对肾纤维化的影响及其相关分子机制。通过血尿素氮（BUN）和血清肌酐（Scr）水平以及尿白蛋白肌酐比（ACR）评估肾损伤。通过 IV 型胶原（COLIV）和纤维连接蛋白（FN）蛋白表达以及 Masson 三色染色的组织病理学分析评估肾纤维化。通过 Western blot 测定 COLIV、FN、NF-κB 抑制剂α（IκBα）、磷酸化 IκBα（p-IκBα）、p65、磷酸化 p65（p-p65）和 Toll 样受体 4（TLR4）的蛋白水平。通过 RT-qPCR 测定 miR-124 和 TLR4 mRNA 水平。通过生物信息学分析、荧光素酶报告基因测定和 RIP 测定检测 miR-124 和 TLR4 的相互作用。黄芩苷或 miR-124 减轻 STZ 诱导的 DN 小鼠的肾损伤和纤维化。黄芩苷通过上调 HK-2 细胞中的 miR-124 抑制 HG 诱导的 COLIV 和 FN 表达增加。TLR4 是 miR-124 的靶标。miR-124 抑制 TLR4/NF-κB 通路激活，NF-κB 通路失活抑制 HG 刺激的 HK-2 细胞中 COLIV 和 FN 的表达。黄芩苷通过增加 miR-124 并使下游 TLR4/NF-κB 通路失活来预防 DN 中的肾纤维化，提示黄芩苷和 miR-124 在 DN 和肾纤维化管理中的重要价值。
