Figure 1: The experimental cells serum resistance response. +LHC-8 serum free medium added 10% fetal bovine serum; -LHC-8 serum free medium did not add 10% fetal bovine serum. A. Response of BEAS-2B cells in LHC-8 serum free medium. B. Response of BEAS-2B cells in LHC-8 serum free medium added 10% fetal bovine serum. C. Response of BEAS- 2BNNk cells in LHC-8 serum free medium. D. Response of BEAS-2BNNk cells in LHC-8 serum free medium added 10% fetal bovine serum. •P<0.01; *P<0.01.