After isolation, keratinocytes were cultured in Keratinocyte Growth Medium
(KGM) supplemented with KGM supplement mix (both from PromoCell, Heidelberg, Germany) and 1% penicillin/streptomycin (Life Technologies GmbH, Darmstadt, Germany).
For culture of keratinocytes or fibroblast, keratinocyte growth medium
(KGM, Clonetics, San Diego, CA) or Dulbecco's modified Eagle's medium (DMEM) (LM001-05, WelGENE, Daegu, South Korea) supplemented with 10% fetal bovine serum (FBS, Thermo Scientific HyClone, Logan, UT) was used.
RPMI-1640 medium and human keratinocyte growth medium
were purchased from Nissui Pharm.
Cells were treated as follows: keratinocyte growth medium
(KGM) was supplemented with epidermal growth factor, insulin, hydrocortisone, antimicrobial agents, and bovine pituitary extract.