Effects of 3-isobutyl-1-methylxanthine and kojic acid on cocultures and skin equivalents composed of HaCaT cells and human melanocytes

Excerpt

During the last decade, a variety of skin equivalent models have been developed to provide useful models for investigations of skin physiology. Epidermis reconstructs based on fibroblast-populated collagen matrices are widely used especially for toxicological and pharmacological investigations. At present, there is a special focus on the regulation of skin pigmentation by melanogenic stimulators or inhibitors. Since skin pigmentation is ultimately controlled by melanin-producing melanocytes interspersed in the epidermis the most simple model is melanocyte monoculture (Virador et al. 1999; Yoshimura et al. 2001). However, melanin production in melanocytes is influenced by keratinocytes and fibroblasts (Hedley et al. 2002; Lei et al. 2002). Therefore, coculture models composed of keratinocytes and melanocytes (Lei et al. 2002) as well as different stratified three-dimensional skin equivalent models have been developed (Archambault et al. 1995; Bessou et al. 1995, 1997; Regnier et al. 1999; Todd et al. 1993). These skin models show altered pigmentation as a result of melanin transfer from melanocytes to keratinocytes after treatment with regulators of pigmentation (Bessou et al. 1997). …