Study On The Mechanism Of Human Bronchial Epithelium Injured By Black Powder Smoke And The Protective Effect Of Puerarin

Objective1. In vitro human bronchial epithelial cell model injured by blackpowder smoke was established.2. The mechanism of human bronchial epithelial cellsinjured by black powder smoke and the inhibition effect of puerarin was investigated bystudying the upregulation of gene expression, increase of protein synthesis and releaseof certain inflammatory cytokines induced by black powder smoke with or withoutpuerarin intervention. Methods1. In vitro human bronchial epithelial cell injurymodel was established on the basis of former experiments.2. After stimulated by blackpowder smoke, human bronchial epithelial cells’ viability was tested by MTT.3.According to cell viability, cells were randomly divided into five groups:①controlgroup (the human bronchial epithelial cells were normally cultured for36hours);②black powder smoke injury group (the human bronchial epithelial cells were exposed toblack powder smoke for10minutes);③puerarin pretreatment group(the humanbronchial epithelial cells were exposed to black powder smoke for10minutes afterpretreatment with puerarin with the dosage of25,50and100μg/ml).4.24hours afterthe cells were injured by black powder smoke, the level of inflammatory cytokines incell culture supernatant of each group were determined through ELISA.5. The geneexpression of inflammatory cytokines secreted by human bronchial epithelial cells werequantified by real-time PCR at2hours,6hours,8hours and12hours after injured byblack powder smoke. Results1. The viability of human bronchial epithelial cellsdeclined after injured by black powder smoke (P<0.05). While puerarin was added, thecells’ viability greatly increased in a dose-dependent manner (P<0.01).2. After thehuman bronchial epithelial cells were irritated with black powder smoke, the content of inflammatory cytokines IL-8(P<0.05) and IL-6(P<0.01) in the cell culture supernatantincreased. However, puerarin effectively inhibited the secretion of IL-8and IL-6in adose-dependent manner (P<0.01).3. The gene expression of IL-8and IL-6in humanbronchial epithelial cells irritated with black powder smoke was upregulated after injury(P<0.01). When different concentrations of puerarin were added to the cells, the geneexpression of IL-8and IL-6in the cells was significantly inhibited at8hours afterinjury in a dose-dependent manner (P<0.01). Conclusions:1. Black powder smoke candamage in vitro human bronchial epithelial cells by upregulating the gene expressionand inducing the sythesizing and releasing of inflammatory cytokines IL-8and IL-6.2.Puerarin can prevent human bronchial epithelial cells from injuring by black powdersmoke through downregulating the gene expression of inflammatory cytokines IL-8andIL-6and therefore inhibiting the synthesis and secretion of these proteins.