Abstract
Objectives: :
To study the inhibitive effects of Estrogen on the development of the cultured rat lens opacity induced by hydrogen peroxide and observe the change of epithelial cells apoptosis.
Methods: :
One hundred and twenty lenses were obtained from normal adult female and male SD rats (60 lenses from female rats, 60 lenses from male rats). The transparent lenses were randomly divided into 4 groups: the control, the H2O2 (500µM) treatment, the H2O2(500µM) plus 17beta–estrodial (17ß–E2)(8µM) treatment and the 17ß–E2 (8µM) treatment group. During culture, lens opacity was observed under the light microscope. At the time of 24, 48 and 72 hrs, the extent of cells apoptosis was assessed by the method of TUNEL. The ultra–structure of apoptotic cells was observed under the transmission electron microscope.
Results: :
H2O2 (500µM) induced opacity of the cultured rat lenses and the opacity was worsen as the culture proceeded. 17ß–E2 (8µM) reduced the opacity of the female rat lenses treated with H2O2 (P<0.05), but did not of the male ones (P>0.05). The cellular apoptosis rate of female rat lenses between H2O2–treated and H2O2 plus 17ß–E2–treated group was significant (P<0.05), but the rate of the male ones between the above two groups was not significant (P>0.05). There was no difference between 17ß–E2–treated and control group (P>0.05). Under the transmission electron microscope, in the H2O2–treated group the most cells were apoptosis at 72 hours with typical morphological changes, but in the H2O2 plus 17ß–E2–treated group the cell apoptosis was not obvious.
Conclusions: :
Estrogen does not do any harm to the cultured rat LEC. Probably, estrogen provides sex–dependent protection against cataract by countering the oxidative insult and inhibiting H2O2–induced cells apoptosis.
Keywords: cataract • apoptosis/cell death • drug toxicity/drug effects