METHODS: Mice were randomly divided into two experimental groups. C57BL/6 mice inoculated intraperitoneally with PA and then challenged intratracheally both on day 14 and day 28 with PA were investigated as sarcoid-fibrosis group. Mice inoculated and challenged on day 14 with PA while gave PBS challenging on day 28 were sarcoid-remission group. PBS inoculation and challenging on day 0, day 14 and day 28 were taken as negative control group. Inflammation, granuloma and fibrosis features were evaluated every 7 days from day 21 to day 70.