BackgroundReactive oxygen species (ROS) levels largely determine pulmonary fibrosis. Antioxidants have been found to ameliorate lung fibrosis after long-term paraquat (PQ) exposure. The effects of antioxidants, however, on the signalling pathways involved in PQ-induced lung fibrosis have not yet been investigated sufficiently. Here, we examined the impacts of ligustrazin on lung fibrosis, in particular ROS-related autophagy and pro-fibrotic signalling pathways, using a murine model of PQ-induced lung fibrosis.MethodsWe explored the effects of microRNA-193 (miR-193a) on Hedgehog (Hh) and PI3K/Akt/mTOR signalling and oxidative stress in lung tissues. Levels of miR-193a, protein kinase B (Akt), phosphoinositide 3-Kinase (PI3K), ceclin1, mammalian target of rapamycin (mTOR), sonic hedgehog (SHH), myosin-like Bcl2 interacting protein (LC3), smoothened (Smo), and glioma-associated oncogene-1 (Gli-1) mRNAs were determined with quantitative real-time PCR. Protein levels of PI3K, p-mTOR, p-Akt, SHH, beclin1, gGli-1, LC3, smo, transforming growth factor-β1 (TGF-β1), mothers against DPP homologue-2 (Smad2), connective tissue growth factor (CTGF), collagen I, collagen III, α-smooth muscle actin (α-SMA) nuclear factor erythroid 2p45-related factor-2 (Nrf2), and p-Smad2 were detected by western blotting. In addition, α-SMA, malondialdehyde, ROS, superoxide dismutase (SOD), oxidised and reduced glutathione, hydroxyproline, and overall collagen levels were identified in lung tissues using immunohistochemistry.ResultsLong-term PQ exposure blocked miR-193a expression, reduced PI3K/Akt/mTOR signalling, increased oxidative stress, inhibited autophagy, increased Hh signalling, and facilitated the formation of pulmonary fibrosis. Ligustrazin blocked PI3K/Akt/mTOR and Hh signalling as well as reduced oxidative stress via increasing miR-193a expression and autophagy, all of which reduced pulmonary fibrosis. These effects of ligustrazin were accompanied by reduced TGF-β1, CTGF, and Collagen I and III expression.ConclusionsLigustrazin blocked PQ-induced PI3K/Akt/mTOR and Hh signalling by increasing miR-193a expression, thereby attenuating PQ-induced lung fibrosis.

Panax notoginseng saponins are extracted from Chinese ginseng— Panax notoginseng Ledeb —and are known to have therapeutic anti-inflammatory effects. However, the precise mechanism behind their anti-inflammatory effects remains relatively unknown. To better understand how Panax notoginseng saponins exert their therapeutic benefit, we tested them in a rat model of severe acute pancreatitis (SAP). Rats received a tail vein injection of Panax notoginseng saponins and were administered 5% sodium taurocholate 2 h later. Pancreatic tissue was then harvested and levels of miR-181b, FSTL1, TREM1, TLR4, TRAF6, IRAK1, p-Akt, p-p38MAPK, NF-κBp65, and p-IκB-α were determined using Western blot and quantitative real-time polymerase chain reaction (qRT-PCR). Enzyme-linked immunosorbent assays were used to determine serum levels of tumor necrosis factor-α (TNF-α), TREM1, interleukin (IL)-6, ACAM-1, IL-8, and IL-12 and DNA-bound levels of NF-KB65 and TLR4 in pancreatic and ileum tissue. Serum levels of lipase and amylase, pancreatic myeloperoxidase (MPO) activity, and pancreatic water content were also measured. Hematoxylin and eosin staining was used for all histological analyses. Results indicated upregulation of miR-181b, but negligible levels of FSTL1, p-p38MAPK, TLR4, TRAF6, p-Akt, IRAK1, TREM1, p-NF-κBp65, and p-IκB-α, as well as negligible DNA-bound levels of NF-KB65 and TLR4. We also observed lower levels of IL-8, IL-6, ACAM-1, TNF-α, MPO, and IL-12 in the Panax notoginseng saponin–treated group when compared with controls. In addition, Panax notoginseng saponin–treated rats had significantly reduced serum levels of lipase and amylase. Histological analyses confirmed that Panax notoginseng saponin treatment significantly reduced taurocholate-induced pancreatic inflammation. Collectively, our results suggest that Panax notoginseng saponin treatment attenuated acute pancreatitis and pancreatic inflammation by increasing miR-181b signaling. These findings suggest that Panax notoginseng saponins have therapeutic potential in the treatment of taurocholate-induced SAP.