Protoporphyrin IX Synthesis Induced by 5-aminolevulinic Acid and Its Esters in Normal Mouse Skin

Kim, Hyung Sung; Na, Eui Young; Yun, Sook Jung; Kim, Seong Jin; Lee, Seung Chul; Won, Young Ho; Park, Hyoung Ryun; Lee, Jee Bum

Abstract

BACKGROUND: Photodynamic therapy with using 5-aminolevulinic acid (ALA) is a good noninvasive treatment modality that can treat several cutaneous diseases. Yet hydrophilic ALA is not able to easily penetrate the cellular membrane or the lipid layer of the skin. Thus, various ALA alkyl esters been developed.
OBJECTIVE
We studied whether novel ALA unsaturated alkyl esters synthesize more protoporhyrin IX (PpIX) than does ALA in mouse skin tissues.
METHODS
We applied 5, 10, 15% ALA and ALA esters ointment to the skin of shaved mice, respectively. We harvested the skin tissue, made a preparation and did quantitative analysis according to the fluorescent spectrum for determining the amount of PpIX synthesized in the skin after the elapse of 1 hour and 3 hours, respectively.
RESULTS
No matter what the sort or the concentration of the ALA and ALA ester was, the amount of synthesized PpIX increased more after the elapse of 3 hours than that after 1 hour. ALA (hetenyl-, petenyl-, butenyl-, methyl-) esters tended to produce a much greater amount of PpIX than ALA. According to the results of the comparative study with using 5%, 10% and 15% of ALA and ALA esters ointment, the amount of synthesized PpIX was not proportional to the concentration of the ALA and the ALA esters, even though the ALA esters produced more PpIX than the ALA.
CONCLUSION
We found that the ALA unsaturated alkyl esters are a good photosensitizer and they are similar to ALA-me, which is an ALA saturated alkyl ester that induces more PpIX, an actual photosensitizer, than ALA can.