ABSTRACT
ObjectiveTo explore the effect and underlying mechanism of alcohol extract of Phyllanthi Fructus on silicosis mice induced by silicon dioxide （SiO2）. MethodThirty-six male Kunming mice of SPF grade were randomly divided into a blank group，a model group，high-， medium， and low-dose Phyllanthi Fructus groups （800， 400， 200 mg·kg-1），and a tetrandrine group （0.039 mg·kg-1），with six mice in each group. The silicosis model was induced by static SiO2 exposure in mice except for those in the blank group. After 28 days of administration by gavage，the lung tissues were collected and the organ coefficient was calculated. Hematoxylin-eosin（HE）staining and Masson staining were used to detect the morphology of lung tissues. The content of hydroxyproline （HYP），superoxide dismutase （SOD），malondialdehyde （MDA）， and catalase （CAT） in serum was detected by enzyme-linked immunosorbent assay （ELISA）. Western blot and Real-time polymerase chain reaction（Real-time PCR） were used to detect the protein and mRNA expression of nuclear factor E2-related factor 2 （Nrf2），heme oxygenase-1 （HO-1），NAD（P）H：quinone oxidoreductase 1 （NQO1），and Kelch-like ECH-associated protein 1 （Keap1）， respectively. ResultCompared with the blank group，the model group showed seriously damaged morphological structure of lung tissues with inflammatory cell infiltration and fibrous tissue proliferation， reduced serum content of SOD and CAT（P<0.01），increased content of HYP and MDA（P<0.01）， down-regulated protein and mRNA expression of Nrf2，HO-1， and NQO1（P<0.01），and up-regulated protein and mRNA expression of Keap1 （P<0.05，P<0.01）. Compared with the model group，the high- and medium-dose Phyllanthi Fructus groups showed significantly restored morphological structure of lung tissues with reduced collagen deposition， increased serum content of SOD and CAT（P<0.05，P<0.01），decreased content of HYP and MDA（P<0.01）， up-regulated protein and mRNA expression of Nrf2，HO-1， and NQO1 （P<0.05，P<0.01），and down-regulated protein and mRNA expression of Keap1（P<0.05，P<0.01）. ConclusionThe alcohol extract of Phyllanthi Fructus can inhibit pulmonary fibrosis in silicosis mice，and the underlying mechanism may be related to the regulation of the Nrf2/antioxidant response element （ARE） signaling pathway.