Résumé
Objective To study inflammatory reaction induced by N-protein of severe acute respiratory syndrome(SARS)-coronavirus(CoV)in human alveolar typeⅡepithelial cell(A549). Methods Effects on growth of A549 cell by N-protein of SARS-CoV:activity of A549 cells was determined by thiazylyl blue colorimetry assay at 24,48,72 and 96 h,respectively.Effects on cyto- kine production by A549 cells exposed to N-protein of SARS-CoV:interleukin(IL)-6,IL-10 and transforming growth factor-?1(TGF-?1)concentration in culture supernatant were determined by enzyme-linked immunosorbent assay(ELISA).Effects on mRNA expression of cytokine of A549 cells and matrix metalloproteinases-9(MMP-9)exposed to N-protein of SARS-CoV:total RNA of A549 cells was extracted using Rneasy mini kit;RT-PCR was employed to measure the mRNA expression of IL-6,IL-10,TGF-?1 and MMP-9 semiquantitatively.Results Different concentrations of N-protein could all inhibit the growth of A549 cells(after 48 h)and the inhibition by 20?g/mL pro- tein was the strongest.Compared with the control group(0.737?0.024,0.968?0.007),the A val- ues of experimental groups at 72 h and 96 h(0.672?0.027,0.799?0.092)decreased obviously (P