Stimulated mouse ear epidermis in explant culture- The effect of retinoic acid and hexadecane

Comparison of the enzymatic and explant methods for the culture of keratinocytes isolated from human foreskin

Currently, culture and growth keratinocytes are important stages in achieving a reliable and reproducible skin tissue. In the present study, two different methods, enzymatic and explant methods, for keratinocytes isolation from human foreskin were compared. Foreskins were cut into 2-3 mm pieces and placed in trypsin at 4°C overnight for separation of the epidermis from the dermis. Subsequently, these samples were divided into two groups: i) Keratinocytes separated from the epidermis by trypsin and ii) by the explant method. These keratinocytes were divided into two groups: i) With no feeder layer and ii) onto a type I collagen scaffold. The cells were evaluated using immunocytochemistry and 4',6-diamidine-2'-phenylindole dihydrochloride (DAPI) staining. In the enzymatic treatment, after 7-10 days no attached cells were found in the cell culture dishes. In the explant method, keratinocytes were separated after ~24 h, attached rapidly and formed big colonies into a collagen scaffold. In the absence of a feeder layer, small colonies were developed with rapid loss of proliferation within 2-3 days. Keratinocytes showed positive immunoreactivity for the pan-cytokeratin marker and keratinocytes' nuclei were clearly observed. This method could be applied and developed as a component of skin substitutes to treat burns and wounds and also in laboratory testing.

Skin explant cultures as a source of keratinocytes for cultivation

Cultivated human keratinocytes can be used successfully in the treatment of burn patients, but efforts to heal burns and other wounds can be hampered by the very small skin biopsies available for cultivation of transplantable keratinocyte sheets. A small biopsy (and correspondingly small number of enzymatically isolated keratinocytes for use in classical cultivation techniques) can lead to a low yield of multilayer sheets for clinical application or unacceptably long cultivation times. One way of addressing this is to make use of skin remnants remaining after enzymatic digestion and culture cells migrating out of these skin explants. Sufficient numbers of explant-derived keratinocytes can be obtained to facilitate additional routine cultivation of these cells. Biopsy remnants can be used to initiate explant cultures repeatedly (we were able to re-use pieces of skin 10 times and still obtain useful numbers of keratinocytes) and this "passaging" yields substantially more cells for classical cultivation than would be available from conventional methodology alone, and in a comparable timeframe. Another advantage of this method is that it does not require additional biopsies to be procured from already-compromised patients and overcomes problems associated with contamination of skin samples with resistant hospital-acquired bacterial infections common during prolonged hospitalization.