Although normal human oral keratinocyte(NHOK) in tissue is terminally differentiated into cornified epithelium as skin epidermal cell, these cells are different from the characteristics of normal human skin keratinocyte(NHEK).
The purpose of this study were to examine a comparative study of optimum medium requirement and calcium concentration on cultured NHEK and NHOK, and to apply this culture condition to study oral diseases and tumors in future. NHEK from foreskin and NHOK from healthy retromolar pad(Dept. of OMFS of DKDU) were primarily cultured in KBM bullet kit. Cultured NHEK and NHOK were divided into 5 groups as G1(KBM bullet kit), G2(-EGF), G3(-Insulin) and G4(-Hydrocortisone) according to medium conditions to get a growth curve, respectively. According to 0.05, 0.15, 1.2 mM Ca concentration, cultured NHEK and NHOK were harvested to take growth curve, cornified envelop measurement and TGase activity assay of NHEK and NHOK, respectively. The obtained results were as follows.
1. Primary cultured NHEK and NHOK showed a mixture of basal, suprabasal, and cornified cells. Doubling time(about 25 hrs) of NHEK grown in 0.05mM calcium was similar to that of cultured NHOK in 0.15mM.
2. Cultured NHEK showed single layer of relatively flattened epithelial cells in 0.05mM calcium, a small foci of stratification in 0.15mM and large areas of stratification, more compact, with irregular border and tightly apposed cells in 1.2mM.
3. Cultured NHOK showed single layer of relatively well defined epithelial cells in 0.05mM calcium, single layer of polygonal epithelial cells, a small foci of stratification in 0.15mM and similar features to that of cultured NHEK in 1.2mM.
4. Abscence of hydrocortisone showed more inhibitory effect on cultured NHOK than that NHEK.
5. During the terminal differentiation in cultured NHEK and NHOK irrespective of calcium concentration, increased insoluble cornified cell envelope formation was accompanied with induction of TGase 1 activity.
From the aboving results, it was suggested that although optimum calcium concentration of cultured NHEK(0.05mM) was different from cultured NHOK(0.15mM), NHEK and NHOK with high selectivity against fibroblasts were well grown under this medium containing specific factors.
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