DAMAGE TO CULTURED LENS EPITHELIAL-CELLS OF SQUIRRELS AND RABBITS BG UV-A (99.9-PERCENT) PLUS UV-B (0.1-PERCENT) RADIATION AND ALPHA-TOCOPHEROL PROTECTION
S. Zigman et al., DAMAGE TO CULTURED LENS EPITHELIAL-CELLS OF SQUIRRELS AND RABBITS BG UV-A (99.9-PERCENT) PLUS UV-B (0.1-PERCENT) RADIATION AND ALPHA-TOCOPHEROL PROTECTION, Molecular and cellular biochemistry, 143(1), 1995, pp. 35-46
The purpose of this research is to observe the near-UV radiation induc
ed damage to cultured rabbit and squirrel lens epithelial cells as rel
ated to destruction and alterations of specific biochemical targets in
the cells and to determine protective effects on the cells and target
s that are provided by alpha-tocopherol. Confluent monolayers of cultu
red rabbit and squirrel lens epithelial cells were exposed to black li
ght (BL) lamps, which emit predominantly UV-A radiation. These cells r
eceived a mixture 3 J/cm(2) of UV-A and 4 mJ/cm(2) of UV-B per h. This
mixture is termed near UVA (ie: predominantly UV-A). Cells were expos
ed in Tyrode's or in MEM without or with alpha-tocopherol added at 2.5
-10 mu g/ml. Analyses of cell viability and survival, the physical sta
te of cytoskeletal actin, and the activities of Na-K-ATPase and catala
se were made. Exposure to near UVA damaged these cells as measured by
vital staining and colony forming ability. Pretreatment with alpha-toc
opherol decreased the magnitude of near UVA cytotoxicity. Near UVA exp
osure in MEM always produced more damage to the cells and biochemical
targets than in Tyrode's. Cytoskeletal actin was degraded and the acti
vities of Na-K-ATPase and catalase were markedly inhibited by UV-expos
ure. All of these targets were at least partially protected by alpha-t
ocopherol in the medium. Without alpha-tocopherol added to the media,
the viability and survival of the cells did not recover even after 25
h of incubation. Cell viability was better protected from near UVA by
alpha-tocopherol than was the ability to grow into colonies. This indi
cates that alpha-tocopherol protects actin, catalase, and Na-K-ATPase
from near UVA damage.