“…Hamster sebocytes were cultured in DMEM /F12 supplemented with 6% heat‐denatured fetal bovine serum (JRH Bioscience, Tokyo, Japan), 2% human serum (ICN Biochemicals, Costa Mesa, CA, USA), 0.68 mmol/L l ‐glutamine (Invitrogen, Carlsbad, CA, USA), and recombinant human epidermal growth factor (10 nmol/L) (Progen Biotechnik GmbH, Heidelberg, Germany) as previously described 22 . For PGE 2 and pro‐MMP‐2 production, the cells were treated for 24 h with NDFX (10–50 μg/mL) (kindly provided by Otsuka Pharmaceutical Co., Tokyo, Japan) or CLDM hydrochloride (10–50 μg/mL) (AppliChem GmbH, Darmstadt, Germany) in the presence or absence of PGN (5–50 μg/mL) from Staphylococcus aureus (Sigma Chemical, St Louis, MO, USA) in Dulbecco’s modified Eagle’s medium (DMEM)/F12 supplemented with 0.2% lactalbumin hydrolysate (Sigma Chemical, St Louis, MO, USA) 16,24 . In this series of experiments, hamster sebocytes were used as far as the third passage level.…”