Abstract
To clarify the usefulness of fluorescent diagnosis for cancer, We investigated the optimal method of administrating 5-aminolevulinic acid(5-ALA) by analyzing fluorescence signal of Protoporphyrin IX(PpIX) in the cultured normal and cancer cells. 5-ALA was injected as a photosensitizer to the cervico-uterine cancer cell line(HeLa) and in normal liver cells(Chang). Chang and HeLa cells were incubated with various concentrations of 5-ALA($0-800{\mu}g/ml$). The accumulation of PpIX induced by 5-ALA was in HeLa and Chang cells. The cell viability was measured by MTT assay. The optimal concentration of ALA that induced maximum levels of PpIX was $50{\mu}g/ml$ in HeLa cell cultured for 24 hours after 5-ALA injection. Fluorescence of PpIX in HeLa cell was excited at a wavelength(${\lambda}$=410 nm) and showed an emission spectrum at 602.3 nm, 659.9 nm which could be related to the PpIX generation induced by the applied 5-ALA. The experimental results showed that fluorescence signal of PpIX was proportional to the concentration of 5-ALA in cancer cells, but measured with low concentration in normal cells.
형광을 이용한 암 진단을 위해 배양된 정상 및 암세포주에 광민감제인 5-ALA를 투여하고 세포 내 외에서 생성된 Protoporphyrin IX(PpIX)의 형광을 측정하여 5-ALA 투여의 최적농도를 조사하였다. 정상 간세포주(Chang) 및 자궁경부암 세포주(HeLa)에 5-ALA를 농도별로 투여하여 ALA에 의해 유도된 PpIX의 생성을 확인하고, MTT assay로 세포생존율을 측정하였다. 배양된 cell에 5-ALA를 투여한 후 24시간 동안 배양함으로써 생성되는 PpIX의 양은 형광의 강도로 측정하였다. HeLa 세포주에 대한 5-ALA의 최적농도는 $50{\mu}g/ml$이며, 이 때의 형광(emission) 스펙트럼은 여기 파장이 410 nm일 때 602.3 nm, 659.9 nm에서 형광 봉우리가 관찰되었다. PpIX의 형광 강도를 측정한 결과, PpIX는 정상세포에서는 낮은 농도로 축적이 되는 반면에 암세포에서 더 높은 농도로 축적되었으며, 세포 외보다는 세포 내에서 더 높은 농도로 축적됨을 알 수 있었다.
