KC Ngai, CY Yeung, CS Leung

Aims Bilirubin has been found to be toxic to many cells, such as fibroblasts, hepatocytes, erythrocytes, leucocytes, HeLa cells, and platelets. Clinically bilirubin damage is manifested mainly as abnormalities of the central nervous system. This suggests a difference in the susceptibility to bilirubin toxicity of different tissues or cells.

Materials and Methods To test the validity of this hypothesis, we used a modified 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide method (1,2) to study the cytotoxic effect of bilirubin on various commercially available cell lines in culture. A human glioblastoma cell line (ATCC CRL 1690, T98G), human neuroblastoma cell line (ATCC HTB-10, SK-N-MC), human liver cell line (ATCC CCL 13, Chang Liver, Hela markers) and a mouse fibroblast cell line (ATCC CCL-1, NCTC Colone 929) were used.

Results Cytotoxicity usually occurred when a certain bilirubin:albumin molar ratio was exceeded in the medium of a growing cell line in culture. Different cells exhibited different susceptibilities to the cytotoxic effects of bilirubin; neuroblastoma and glioblastoma were most susceptible, fibroblasts were the least vulnerable among the cell lines tested.

Conclusions Our findings confirmed the clinical impression that different cells suffer different degrees of cytotoxicities caused by bilirubin.

Acknowledgements This study was supported by the CRCG grant, No 337/045/00 10, the University of Hong Kong.

References

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2. Denizot F, Lang R. Rapid colorimetric assay for cellular growth and survival modifications to tetrazolium dye procedures giving improved sensitivity and reliability. J Jmmunol Method 1986;89:271-77.