RESUMEN
The cell-killing effect and its possible mechanism of berberine used alone or in combination with argon ion laser treatment on 9L rat glioma cells were studied. The survival fraction of 9L cells after single treatment of berberine has been investigated using both colony formation and microtitration (MTT) method, the half lethal dose of berberine (LD50) has been estimated to be 60 micrograms/ml. After the addition of low energy laser treatment, the LD50 of berberine markedly decreased to 10 micrograms/ml. The inhibitory effect of berberine on biosynthesis for DNA, RNA, and protein of 9L cells was enhanced by argon ion laser. Moreover, when morphologic change was examined, the 9L cells showed lysis, encystation, and degeneration after berberine treatment; the laser treatment enhanced the cell-killing effect. The study proves the cell-killing effect of berberine combined with laser treatment on 9L rat glioma cell line, hence introducing the possibility of berberine as a photosensitive agent.