Niaodukang mixture inhibits micro-inflammation in CKD rats by enhancing MiR-146a levels in enterogenous exosomes

Abstract

Ethnopharmacological relevanceThe Niaodukang mixture (NDK) is a preparation known for its ability to lower serum creatine levels in individuals with chronic kidney disease (CKD) and is commonly administered at medical facilities like the Zhongshan Hospital of Traditional Chinese Medicine. The initial use of NDK was mainly to treat CKD. Our hospital frequently utilizes NDK, which consists of Rheum officinaleBaill., Salvia miltiorrhiza Bunge., Astragalus aaronii (Eig) Zohary., Carthamus tinctorius L., and Sanguisorba officinalis L., for treating patients with CKD-MBD. It has the effects of eliminating dampness and turbidity and dredging kidney collaterals. However, The impact and process of NDK in chronic kidney disease remain unknown. Aim of the studyTo determine whether microRNA-146a (miR-146a) is associated with CKD micro-inflammationand whether NDK protects against CKD micro-inflammation by modulating the miR-146a/nuclear factor kappa-B (NF-κB) signaling pathway. Materials and methods(1) An adenine-induced rat model of chronic kidney disease was created through the use of materials and methods. The levels of miR-146a in exosomes from plasma and ileum were determined by RT-PCR. (2) Human cloned colon adenocarcinoma (Caco-2)cellswere stimulated with lipopolysaccharide (LPS)and transfected with miR-146a mimic and inhibitor. Following that, the Western blot and RT-PCR techniques were used to measure the protein and mRNA quantities of Toll-like receptor 4 (TLR4), NF-κB, and TNF receptor-associated factor 6 (TRAF6). (3) Enzyme-linked immunosorbent assay (ELISA) was used to identify serum levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α). (4) Plasma exosomes were extracted, and the exosomes in intestinal tissues were extracted via ultrahigh-speed centrifugation.Negative staining electron microscopy was used to analyze the morphology of exosomes and the ultrastructure of intestinal tissue and exosomes. The particle size of the exosomes was measured using nanoparticle tracking analysis. ResultsThe pathological characteristics of CKD rats included those associated with systemic micro-inflammation, which may be associated with the release of exosomes in intestinal tissue. NDK suppressed the inflammatory response in Caco-2 cells and decreased the levels of IL-1β, IL-6, and TNF-α in rats with CKD. The expression of miR-146a, which regulates inflammation, differed between plasma-derived and enterogenous exosomes in CKD rats, which may be due to stimulation of ileal exosome release into the blood. NDK effectively reduced the levels of TRAF6, NF-κB, and TLR4 in the ileum tissue of CKD rats. ConclusionNDK can effectively improve micro-inflammation in CKD ratsby enhancing the release of enterogenous exosomes, thereby enhancing the release of exosome-associated miR-146a and inhibiting micro-inflammation.