Optimized growth medium for primary culture of human oral keratinocytes

The effect of different media additives in defining optimal growth conditions for primary cultures of human oral keratinocytes was studied. A cocultivation technique with irradiated Swiss-3T3-fibroblasts in 96-well plates enables the comparison of additives for primary keratinocyte cultures derived from one patient. H-3-labeled thymidine uptake showed no growth or growth inhibition with adenine, choleratoxin or transferrin compared to basal medium (Dulbecco's modified Eagle's medium (DMEM) and 10% fetal calf serum). Among single additives, 5 mu g/ml hydrocortisone, 5 mu g/ml insulin, 10 ng/ml EGF, 2 mu g/ml bovine pituitary extract, and 10(-9) M triiodothyronine showed the greatest capacity to promote keratinocyte growth. With all possible combinations of additives, maximum stimulation was found with a combination of EGF (10 ng/ml), insulin (5 mu g/ml), and hydrocortisone (5 mu g/ml); none of the other combinations were more effective. Our data indicate that in short-term cultures (up to 5 days) various media additives described in the literature are not necessarily required in this system of primary culture of human oral keratinocytes.