姜酚与二甲双胍联合应用通过靶向 miRNA-146a、miRNA-223、TLR4/TRAF6/NLRP3 炎性小体通路和 HIF-1α对高糖高脂饮食/链脲佐菌素诱导的糖尿病肾病大鼠的肾保护作用。

BACKGROUND: MiRNA-146a and miRNA-223 are key epigenetic regulators of toll-like receptor 4 (TLR4)/tumor necrosis factor-receptor-associated factor 6 (TRAF6)/NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome pathway, which is involved in diabetic nephropathy (DN) pathogenesis. The currently available oral anti-diabetic treatments have been insufficient to halt DN development and progression. Therefore, this work aimed to assess the renoprotective effect of the natural compound 6-gingerol (GR) either alone or in combination with metformin (MET) in high-fat diet/streptozotocin-induced DN in rats. The proposed molecular mechanisms were also investigated. METHODS: Oral gavage of 6-gingerol (100 mg/kg) and metformin (300 mg/kg) were administered to rats daily for eight weeks. MiRNA-146a, miRNA-223, TLR4, TRAF6, nuclear factor-kappa B (NF-κB) (p65), NLRP3, caspase-1, and hypoxia-inducible factor-1 alpha (HIF-1α) mRNA expressions were measured using real-time PCR. ELISA was used to measure TLR4, TRAF6, NLRP3, caspase-1, tumor necrosis factor-alpha (TNF-α), and interleukin-1-beta (IL-1β) renal tissue levels. Renal tissue histopathology and immunohistochemical examination of fibronectin and NF-κB (p65) were performed. RESULTS: 6-Gingerol treatment significantly reduced kidney tissue damage and fibrosis. 6-Gingerol up-regulated miRNA-146a and miRNA-223 and reduced TLR4, TRAF6, NF-κB (p65), NLRP3, caspase-1, TNF-α, IL-1β, HIF-1α and fibronectin renal expressions. 6-Gingerol improved lipid profile and renal functions, attenuated renal hypertrophy, increased reduced glutathione, and decreased blood glucose and malondialdehyde levels. 6-Gingerol and metformin combination showed superior renoprotective effects than either alone. CONCLUSION: 6-Gingerol demonstrated a key protective role in DN by induction of miRNA-146a and miRNA-223 expression and inhibition of TLR4/TRAF6/NLRP3 inflammasome signaling. 6-Gingerol, a safe, affordable, and abundant natural compound, holds promise for use as an adjuvant therapy with metformin in diabetic patients to attenuate renal damage and stop the progression of DN.

背景：miRNA-146a 和 miRNA-223 是 Toll 样受体 4（TLR4）/肿瘤坏死因子受体相关因子 6（TRAF6）/NOD 样受体家族富含亮氨酸重复序列 3（NLRP3）炎症小体途径的关键表观遗传调节剂，该途径参与糖尿病肾病（DN）的发病机制。目前可用的口服抗糖尿病治疗方法不足以阻止 DN 的发展和进展。因此，本研究旨在评估天然化合物 6-姜酚（GR）单独或与二甲双胍（MET）联合应用于高脂饮食/链脲佐菌素诱导的大鼠 DN 中的肾保护作用，并探讨其潜在的分子机制。

方法：大鼠每日口服给予 6-姜酚（100mg/kg）和二甲双胍（300mg/kg），连续 8 周。采用实时 PCR 法检测 miRNA-146a、miRNA-223、TLR4、TRAF6、核因子-κB（NF-κB）（p65）、NLRP3、半胱天冬酶-1 和缺氧诱导因子-1α（HIF-1α）mRNA 的表达。采用 ELISA 法检测 TLR4、TRAF6、NLRP3、半胱天冬酶-1、肿瘤坏死因子-α（TNF-α）和白细胞介素-1β（IL-1β）肾组织水平。进行肾组织病理检查和纤维连接蛋白及 NF-κB（p65）免疫组化检查。

结果：6-姜酚治疗可显著减轻肾脏组织损伤和纤维化。6-姜酚可上调 miRNA-146a 和 miRNA-223，下调 TLR4、TRAF6、NF-κB（p65）、NLRP3、半胱天冬酶-1、TNF-α、IL-1β、HIF-1α和纤维连接蛋白的肾组织表达。6-姜酚还可改善血脂谱和肾功能，减轻肾脏肥大，增加还原型谷胱甘肽，降低血糖和丙二醛水平。6-姜酚与二甲双胍联合应用的肾保护作用优于单独应用。

结论：6-姜酚通过诱导 miRNA-146a 和 miRNA-223 的表达和抑制 TLR4/TRAF6/NLRP3 炎症小体信号通路，在 DN 中发挥关键的保护作用。6-姜酚作为一种安全、经济、丰富的天然化合物，有望与二甲双胍联合用于糖尿病患者的辅助治疗，以减轻肾脏损伤并阻止 DN 的进展。