Investigating Mechanism of Fritillariae Cirrhosae Bulbus Against Pulmonary Fibrosis Based on Spatial Metabolomics / 中国实验方剂学杂志

ABSTRACT

ObjectiveBased on spatial metabolomics technology combined with pharmacological indexes， to analyze the mechanism of Fritillariae Cirrhosae Bulbus（FCB） powder in improving bleomycin-induced pulmonary fibrosis in rats. MethodSixty SD rats were randomly divided into five groups， including the blank group， the model group， and high， medium， low dosage groups of FCB. Except for the blank group， rats in all other groups were injected with bleomycin by tracheal injection to establish a pulmonary fibrosis model. Postoperatively， the high， medium and low dosage groups of FCB were administered aqueous solutions of FCB powder at doses of 0.36， 0.18， 0.09 g·kg-1， respectively， continuously for 28 d. The blank and model groups were given an equal volume of distilled water by gavage. After the last administration， lung tissues and blood samples were collected， the pathological conditions of rat lung tissues were comprehensively evaluated by hematoxylin-eosin（HE） and Masson staining， and aerodynamic assisted desorption electrospray ionization mass spectrometry imaging（AFADESI-MSI） was used for MSI of rat lung tissues from different experimental groups. Spatial metabolomics analysis was conducted on the fibrotic areas of lung tissues in the model group and the high dosage group of FCB based on HE staining images. Differential metabolites between groups were screened by orthogonal partial least squares-discriminant analysis（OPLS-DA）， with variable importance in the projection（VIP） values>1， t-test P<0.05， and fold change analysis. Metabolic pathway analysis of the identified differential metabolites was performed using Kyoto Encyclopedia of Genes and Genomes（KEGG）. Protein expression levels of nuclear transcription factor-κB p65（NF-κB p65） and heme oxygenase-1（HO-1） in rat lung tissues were detected by Western blot. Biochemical assessments of superoxide dismutase（SOD）， malondialdehyde（MDA） and glutathione（GSH） levels in rat lung tissues were conducted. Serum levels of interleukin（IL）-1β， IL-6， nuclear factor erythroid 2 related factor 2（Nrf2）， and tumor necrosis factor-α（TNF-α） were measured by enzyme linked immunosorbent assay（ELISA）， and some of the screened signaling pathways with strong correlation were verified. ResultThe results of MSI experiment showed that after 28 d of the administration of FCB powder to rats with pulmonary fibrosis， the content of L-arginine in the fibrotic regions of lung tissues was significantly different from that of rats in the model group， and the content of phosphatidylcholine was lower than that in the fibrotic region of lung tissues of rats in the model group. Western blot results confirmed that， in comparison to the model group， oral administration of FCB powder for 28 d could inhibit the elevated expression of NF-κB p65 protein in the lung tissues of rats with pulmonary fibrosis. Furthermore， high dose of FCB powder was able to significantly inhibit the expression of HO-1 after oral administration （P<0.05）. The cytokine detection results indicated that the concentrations of IL-1β， IL-6 and TNF-α in the serum of rats from the high， medium， low dosage groups of FCB were reduced by comparing with the model group， and the high dose of Chuanbeimu powder administered by gavage could significantly inhibit the trend of decreased SOD， GSH， Nrf2 contents and increased MDA content induced by bleomycin. ConclusionOral administration of FCB powder has the potential to partially ameliorate bleomycin-induced pulmonary fibrosis in rats， and its mechanism may be related to the regulation of pathways associated with inflammation（NF-κB p65） and oxidative stress（Nrf2/HO-1）.