No abstract

Oleanolic acid (OA), a natural pentacyclic triterpenoid, has been reported to have several benefits and medicinal properties. However, its protective effects against silica‑induced lung injury and fibrosis remain to be elucidated. The aim of the present study was to investigate the effects of OA on oxidative stress, and the expression of cytokines and collagen in silicotic rats. Male rats were induced by intratracheal instillation of silicosis (250 mg/kg), with the exception of the control group (NS). The rats in the OA group were intragastrically administered with OA (60 mg/kg/d). The rats in the solvent control group were gavaged daily with 0.6% sodium carboxymethyl cellulose (10 ml/kg) solution for 56 consecutive days. The data showed that OA significantly attenuated the extent of silicosis fibrosis by histopathologic analysis of the lung tissues. In addition, oxidative stress activated by silica exposure, as evidenced by increasing of malondialdehyde content, and activities of superoxide dismutase and glutathione peroxidase in the lung, was regulated by treatment with OA. Furthermore, enzyme‑linked immunosorbent assay analysis showed that OA significantly decreased the levels of tumor necrosis factor‑α and transforming growth factor‑β1. Immunohistochemistry analysis showed that OA significantly decreased collagen types I and III. In investigating the mechanisms underlying the action of OA, it was found that OA decreased the level of phosphorylated AKT1, which in turn inactivated the transcriptional of nuclear factor (NF)‑κB in the development and progress of silicosis. In conclusion, these results suggested that the protective effects of OA were due, at least in part, to its anti‑oxidant activity and its ability to decrease the expression of cytokines and collagen by modulating the AKT/NF‑κB pathway.

No abstract

To investigate the effect of liposome Lipofectamine® 2000‑mediated HSP27 plasmid transfection in A549 human alveolar type II epithelial cell line on collagen synthesis during transforming growth factor‑β1 (TGF‑β1)‑induced type II epithelial cell transition to myofibroblasts. Cells were transfected with varying ratios of the Lipofectamine® 2000‑mediated heat shock protein 27 (HSP27) plasmid and the transfection efficiency was determined using flow cytometry. The maximum transfection efficacy was confirmed by laser confocal microscopy. HSP gene expression and the most efficient HSP27 plasmid were determined using reverse transcription‑quantitative polymerase chain reaction. Western blot analysis was used to examine HSP27 and collagen expression levels. With a transfection efficiency of 83%, the 8 µg:20 µl ratio of liposome: Plasmid had the highest transfection levels. Among the four different interference sequences in the HSP27 plasmid, the D sequence had the highest interference effect with 70% silencing of the HSP27 gene. The expression of type I and III collagen in TGF‑β1‑induced transition of A549 human alveolar type II epithelial cell line to myofibroblasts was significantly downregulated by the successful transfection with HSP27‑interfering plasmid. The expression of type I and III collagen in the TGF‑β1‑induced transition of A549 cells to myofibroblasts was significantly downregulated by transfection of A549 cells with HSP27 plasmid D‑interfering sequence and optimal ratio of Lipofectamine® 2000 and HSP27 plasmid.