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pyrin-containing结构域3(NLRP3)炎性体途径的关键表观遗传调节因子,参与了糖尿病肾病(DN)的发病机制。目前可用的口服抗糖尿病治疗不足以阻止DN的发展和进展。因此,这项工作旨在评估天然化合物6-姜酚(GR)单独或联合二甲双胍(MET)在高脂饮食/链脲佐菌素诱导的DN大鼠中的肾脏保护作用.还研究了所提出的分子机制。
方法:每天给大鼠口服6-姜辣素(100mg/kg)和二甲双胍(300mg/kg),持续8周。miRNA-146a,miRNA-223,TLR4,TRAF6,核因子-κB(NF-κB)(p65),使用实时PCR检测NLRP3,caspase-1和缺氧诱导因子-1α(HIF-1α)mRNA的表达。ELISA法检测TLR4、TRAF6、NLRP3、caspase-1、肿瘤坏死因子-α(TNF-α),和白细胞介素-1-β(IL-1β)肾组织水平。肾组织病理学检查及纤连蛋白和NF-κB(p65)免疫组化检测。
结果:6-姜酚治疗可显着减少肾组织损伤和纤维化。6-姜酚上调miRNA-146a和miRNA-223,并降低TLR4,TRAF6,NF-κB(p65),NLRP3,caspase-1,TNF-α,IL-1β,HIF-1α和纤连蛋白肾表达。6-姜酚改善血脂和肾功能,减轻肾脏肥大,还原型谷胱甘肽增加,血糖和丙二醛水平下降。6-姜辣素和二甲双胍组合显示出比单独使用任何一种更好的肾脏保护作用。
结论:6-姜酚通过诱导miRNA-146a和miRNA-223表达和抑制TLR4/TRAF6/NLRP3炎性体信号传导在DN中显示出关键的保护作用。6-姜辣素,一个保险箱,负担得起的,和丰富的天然化合物,有望在糖尿病患者中使用二甲双胍作为辅助治疗,以减轻肾脏损害并阻止DN的进展。
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.
CONCLUSIONS: 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.