Characterization and correlation analysis of lung flora in rats with silica-induced acute lung injury / 中国病理生理杂志

ABSTRACT

AIM:To elucidate the possible biological mechanism of silica-induced acute lung injury in rats.METHODS:Sixteen Male Sprague-Dawley rats were divided into control and acute silicosis model groups,and instilled intratracheally with 1 mL of normal saline and 50 g/L silica suspension,respectively.After 7 d,the rats were sacrificed for collection of lung tissue and serum.The serum levels of interleukin-1β(IL-1β),IL-18 and tumor necrosis factor-α(TNF-α)were measured by using ELISA.The protein expression levels of nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)and gasdermin D(GSDMD)were measured by immunohistochemistry.Bacterial DNA was ex-tracted from the lung tissue for 16S ribosomal RNA gene sequencing to characterize changes in the composition of lung flo-ra.The differences in the structure of bacterial flora between control and model groups were analyzed by bioinformatic analy-ses.RESULTS:Immunohistochemical analysis showed that the protein expression levels of NLRP3 and GSDMD were higher in the lungs of the rats in model group.In addition,serum cytokine profiling showed that IL-1β,IL-18 and TNF-α levels were significantly higher in model group.The most abundant bacterial genera in the lung flora of the rats in model group were Bifidobacterium,Clostridium sensu stricto 1,and Parasutterella.The NLRP3 and GSDMD levels in the lung tissue and IL-1β and TNF-α levels in serum were positively correlated with the abundance of Parasutterella.CONCLU-SION:The alterations in lung flora structure and increased inflammation levels may be the actual biological mechanisms underlying silica-induced acute lung injury.The modulation of lung flora may provide a basis for the prevention and treat-ment of silica-induced acute lung injury.