Cytotoxic effect of sodium hypochlorite 0.5% (NaOCl) on ocular melanoma cells in vitro.
OBJECTIVE
Excision with or without adjuvant cryotherapy or brachytherapy is the treatment of choice in conjunctival melanoma. Adjuvant rinsing with alcohol or sodium hypochlorite peroperatively (Dakin's solution) is used in some centers to prevent seeding of melanoma cells. The purpose of this research is to compare the cytotoxicity of sodium hypochlorite (NaOCl) with other potential cytotoxic solutions in the treatment of conjunctival melanoma.


METHODS
Three uveal melanoma cell lines (OCM8, Mel285, and Mel270) and one conjunctival melanoma cell line (CM2005.1) were tested in a proliferation test (CellTiter 96 AQueous One Solution Cell Proliferation Assay, Promega, Madison, WI). The 96-well plates were coated with melanoma cells and treated with sodium hypochlorite 0.5%, sodium bicarbonate (1.4% and 8.4%), ethanol 99%, or sodium chlorite during 3, 5, or 15 minutes. Each solution was tested in several dilutions.


RESULTS
In all cell lines, no surviving cells were observed after treatment of 3 minutes with sodium hypochlorite. Ethanol 99% had a similar effect. A reduction of 70% of viable cells could be reached using sodium bicarbonate 1.4% or 8.4%. Water reduced the amount of viable cells by 40%.


CONCLUSIONS
Sodium hypochlorite is cytotoxic for melanocytic cells in vitro. Its use may reduce local seeding of tumor cells and may decrease metastasis after extirpation of an extended ocular tumour. Further in vivo evaluation of sodium hypochlorite is required.
Missotten
G S
GS
Department Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands. guymissotten@hotmail.com
Keijser
S
S
de Keizer
R J W
RJ
D045744:Cell Line, Tumor / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects*; D002712:Chlorides / Q000494:pharmacology; D003603:Cytotoxins / Q000494:pharmacology* / Q000627:therapeutic use; D000431:Ethanol / Q000494:pharmacology; D005134:Eye Neoplasms / Q000188:drug therapy*; D006801:Humans; D008545:Melanoma / Q000188:drug therapy*; D017693:Sodium Bicarbonate / Q000494:pharmacology; D012973:Sodium Hypochlorite / Q000494:pharmacology* / Q000627:therapeutic use; D013997:Time Factors; D014867:Water / Q000494:pharmacology
D002712:Chlorides; D003603:Cytotoxins; D014867:Water; D000431:Ethanol; D017693:Sodium Bicarbonate; D012973:Sodium Hypochlorite; C001599:chlorite