Protective effects of metallothionein I and II against metal- and ultraviolet radiation-induced damage in cultured lens epithelial cells.
OBJECTIVE
Few quantitative analyses of the induction of metallothioneins (MTs) have been conducted, and there are no reports on the contribution of MTs to the protective mechanism against ultraviolet (UV) radiation in the lens. In this study, we quantitatively analyzed the induction of MTs and analyzed the resulting protective effects against both metal- and UV radiation-induced damage in the cultured lens epithelial cell line, alphaTN4-1.


METHODS
The induction profiles of MTs by ZnCl(2) treatment in alphaTN4-1 cells were analyzed by quantitative real-time reverse transcription polymerase chain reaction. The cells in which MTs were induced were either treated with high concentrations of ZnCl(2) or CdCl(2), or irradiated with UV-C, UV-B, or UV-A radiation, followed by analysis of cell viability. The (3)H-thymidine incorporation rate was used as an indicator of cell viability.


RESULTS
mRNA expression of MT-I and MT-II, the main MT isoform classes, was induced by ZnCl(2) treatment in a dose-dependent manner. MT induction increased the protective effects against both metaland UV-A radiation-induced cell damage.


CONCLUSIONS
Our results suggest that MTs play an important role in the protection against damage induced by both toxic metals and UV-A radiation in lens epithelial cells.
Research Reactor Institute, Kyoto University, Sennan, Osaka, Japan. ta-saito@rri.kyoto-u.ac.jp
Takeshi
T
Saito
Tomoyuki
T
Tezuka
Ryuichi
R
Konno
Noriko
N
Fujii
D000818:Animals; D019256:Cadmium Chloride / Q000633:toxicity*; D002470:Cell Survival; D002478:Cells, Cultured; D002712:Chlorides / Q000633:toxicity; D019610:Cytoprotection / Q000502:physiology*; D004249:DNA Damage / Q000187:drug effects / Q000528:radiation effects; D004260:DNA Repair; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects / Q000528:radiation effects; D007908:Lens, Crystalline / Q000166:cytology* / Q000187:drug effects / Q000528:radiation effects; D008668:Metallothionein / Q000502:physiology*; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014466:Ultraviolet Rays; D017967:Zinc Compounds / Q000633:toxicity
D002712:Chlorides; C491054:Mt2 protein, mouse; D012333:RNA, Messenger; D017967:Zinc Compounds; C525355:metallothionein-1, mouse; C016837:zinc chloride; D008668:Metallothionein; D019256:Cadmium Chloride