The purposes of these experiments were to measure the influence of 14
trace elements on cataractogenesis and to test if these
trace elements could prevent
cataracts induced by
selenium. On days 5-9 postpartum, suckling white rats received daily
subcutaneous injections of either
selenium (0.15 mumoles Se, as Na2SeO3, per pup) or
selenium plus one of 14 other
trace elements (separate
subcutaneous injection) at one to five times the molar concentration of
selenium. The frequency and severity of
cataracts at three locations in the lens were assessed by
slit-lamp examination on day 26-28 postpartum. Seven
ions were found to be effective in preventing
selenium-induced
cataracts (% protection): mercuric (100%),
silver (80%),
cyanide (75%),
arsenite (75%),
cadmium (60%), and cupric (44%).
Tellurite ion offered only 20% protection, while ferrous,
zinc, lead, chromic,
molybdate,
tungstate, and
vanadate ions provided no protection against
selenium-induced
cataract. No significant differences were found between the concentration of
selenium in the
lenses of control and cataractous
lenses when measured approximately three weeks after
selenium injection. Except for
selenium, none of the
trace minerals alone caused
cataracts under our experimental conditions. In addition to
subcutaneous injection of
selenium,
oral administration of this
element was also found to cause
cataract. It was concluded that among the
ions studied,
selenite was a powerful and rapid promoter of nuclear
cataract formation, and that the protection
ions may serve as useful probes for elucidating the mechanism of
selenium-induced
cataracts.