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.

中文翻译：

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黄ical苷通过链脲佐菌素诱导的糖尿病肾病小鼠和高糖治疗的人近端肾小管上皮细胞中的microRNA-124 / TLR4 /NF-κB轴抑制肾纤维化。

肾纤维化是糖尿病肾病（DN）发展中的主要病理事件。黄ical苷是一种黄酮苷，具有多种药理特性，包括抗纤维化活性。在本研究中，在链脲佐菌素（STZ）诱导的DN小鼠模型和高葡萄糖（HG）治疗的HK-2人近端肾小管上皮细胞模型中研究了黄ical苷对肾纤维化的作用以及相关的分子基础。通过血尿素氮（BUN）和血清肌酐（Scr）水平以及尿白蛋白肌酸比（ACR）评估肾脏损伤。肾纤维化通过IV型胶原蛋白（COLIV）和纤连蛋白（FN）蛋白表达以及通过Masson三色染色进行组织病理学分析来评估。COLIV，FN，NF-κB抑制剂α（IκBα），磷酸化IκBα（p-IκBα），p65，磷酸化的p65（p-p65）和toll样受体4（TLR4）通过western blot检测。通过RT-qPCR分析检测MicroRNA-124（miR-124）和TLR4 mRNA水平。miR-124和TLR4的相互作用通过生物信息学分析，荧光素酶报告基因分析和RIP分析进行了检查。黄ical苷或miR-124可减轻STZ诱导的DN小鼠的肾脏损伤和纤维化。黄ical苷通过上调HK-2细胞中的miR-124抑制HG诱导的COLIV和FN表达的增加。TLR4是miR-124的靶标。MiR-124抑制TLR4 /NF-κB通路的活化，而NF-κB通路的失活则阻碍了HG刺激的HK-2细胞中COLIV和FN的表达。黄ical苷可通过增加miR-124并使DN中的下游TLR4 /NF-κB通路失活来预防肾纤维化，