The present study investigated the role of microRNA (miR)‑146a in a diabetic nephropathy (DN) model, and its molecular mechanism. DN mice were given intraperitoneal injections of streptozotocin (55 mg/kg/day) for 5 consecutive days as an in vivo DN model. The HK‑2 human kidney cell line were exposed to 45% D‑glucose as an in vitro DN model. Firstly, it was demonstrated that miR‑146a expression was inhibited and NAPDH oxidase 4 (Nox4) was increased in DN mice. In HK‑2 cells, overexpression of miR‑146a inhibited Nox4 protein expression and decreased reactive oxygen species (ROS) generation, oxidative stress and inflammation, and suppressed vascular cell adhesion molecule‑1 (VCAM‑1) and intracellular adhesion molecule‑1 (ICAM‑1) protein expression. Nacetylcysteine, a Nox4 inhibitor, was demonstrated to inhibit ROS generation, suppress VCAM‑1 and ICAM‑1 protein expression, and decrease oxidative stress and inflammation in HK‑2 cells following overexpression of miR‑146a. In conclusion, these results indicated that miR‑146a/Nox4 decreases ROS generation and inflammation and prevents DN. Therefore, miR‑146a may represent a novel anti‑inflammatory and ‑oxidative modulator of DN.

The active ingredient in Artemisia carvifolia, artemisinin, may alleviate inflammation and toxicity. Artemisinin and its derivatives are first‑line anti‑malarial drugs currently, which have rapid effects on fever caused by malaria parasites with fewer side effects. The present study investigated the effects of Artesunate in a mouse nephritis model. Mice were injected intraperitoneally with 500 µl pristine to induce nephritis, and were treated with 28.8 mg/kg Artesunate. Subsequently, proteinuria, renal function, and tumor necrosis factor (TNF)‑α and interleukin (IL)‑6 levels were assessed to evaluate the effects of Artesunate on nephritis. Western blot analysis was used to measure the protein expression levels of α‑smooth muscle actin (SMA), TLR4, myeloid differentiation primary response gene 88 (MyD88), NF‑κB p65 and transforming growth factor (TGF)‑β1 to investigate the underlying mechanisms of Artesunate on nephritis. The results demonstrated that Artesunate reduced proteinuria and preserved renal function in nephritis mice. Artesunate attenuated TNF‑α and IL‑6 levels, suppressed α‑SMA, TLR4, MyD88, NF‑κB p65 and TGF‑β1 protein expression, and decreased caspase‑3 activity in nephritis mice. These results indicated that the effects of Artesunate may prevent nephritis and inhibit inflammation via the TLR4/NF‑κB signaling pathway in mice. Therefore, Artesunate may be a potential therapeutic agent to prevent nephritis.