ABSTRACT
Other studies have suggested that filter properties of melanin, alone, do not provide sufficient protection against DNA damage in underlying cells. Tadokoro et al. (65) investigated the relationship between melanin and DNA damage after UV exposure in 37 subjects of five ethnic origins (black, white, Asian, others not specified), and Fitzpatrick phototypes I through VI. They found measurable damage to DNA in all groups, and DNA damage was maximal immediately after irradiation, gradually returning to baseline over time. The immediate DNA damage levels were higher in whites and Asians in comparison with blacks and Hispanics. In addition, the whites and Asians showed lower constitutive levels of melanin content. However, the kinetics of DNA damage differed among subjects. Upon monitoring the percentage of removal of damage toward baseline seven days after UV exposure, no correlation was found between melanin content or ethnic group and the efficiency of DNA damage removal. There were variable rates of DNA repair within individual groups indicating that DNA repair rates were not associated with skin type. The authors noted that other properties of melanin, such as antioxidant properties and radical scavenging properties, may play roles in minimizing UV damage. Ethnic differences in expression of receptors involved in melanosome uptake and melanocyte-specific proteins, both before and after UV exposure, are also being investigated.
