The Induction of Heme Oxygenase‐1 by Exogenous Nitric Oxide in ex vivo Normal Human Skin

Gaseous carbon monoxide (CO) has received attention as a neurotransmitter and as a material involved in persistent dilatation of vessels. CO is released by heme oxygenase (HO) during the process from heme to bilirubin or biliverdin. Many reports have revealed that exogenous nitric oxide (NO) can induce HO-1 in vitro, which is the induced isoform of HO. In the present study, we attempted an ex vivo system as an explant culture. A quantitative analysis was performed in combination with a reverse transcription-competitive polymerase chain reaction method, which proved to be very accurate, as well as a qualitative analysis with an immunohistochemistry. With this system we confirmed the induction of HO-1 mRNA and protein by exogenous NO in normal human skin. Our results concluded that this ex vivo system was very useful, because skin samples could be handled easily under conditions close to the in vivo situation.