The Effects Of Estradiol On Lens Epithelial Cells Of Castrated Female Wistar Rat About Expression Of Estrogen Receptor α, Estrogen Receptor β And Survivin

Objective: Cataract is opacity of lens by different kind of reasons. As all known, cataract is the first one of eye diseases that can grow blind. Almost half of the blind today are caused by this disease in China. Cataract is a worldwide serious problem of public health, society and economy. And it is the first eye disease in prevention and cure work.The reasons of causing cataract are varied. For example, ageing , heredity, dysbolism, trauma, radiation, poisoning local nutrition disorders and so on. These reasons can make lens opacity, by damaging to lens epithelial cells and envelope, increasing osmolarity, damaging barrier function, denaturating lens proteins and altering lens fiber structure.Recently,many epidemiological study have found that estrogens can keep lens transparency, prevent lens opacity. But mechanism was not clear why estrogens can keep cataract away. Many study found that estrogens may take effect on lens through antioxidative impairment, maintains normal function of lenticular membrane, TGF-βmediated, estrogen receptor mediated effects and apoptosis. By understood this mechanism, how to make opacity can be known deeply from a point of view; a new method of prevention and cure of cataract may be gotten.In our study, we put adult castrated female Wistar rat randomizated into 6 groups. Each group got estradiol differently in low or high dose, by eyedrops or injections. After that, we observated these lens opacity, appearance under light microscope, and expression of estrogen receptorα,βand Survivin in lens epithelial cells. By doing this, we could found the difference between the ways of useing estrogen, to provide the theoretic foundation and experimental evidence for new means of prevention and therapy on cataract. Methods:Sixty femal Wistar rats were randomly divided into six groups:A. normal(sham operation ,no estradiol)B. ovariectomy(bilateral oophorectomy, no estradiol)C. ovariectomy with low-dose estradiol eyedropping(bilateral oophorectomy, then droping eyes by 50% Estradiol Benzoate parenteral solution four times a day)D. ovariectomy with high-dose estradiol eyedropping(bilateral oophorectomy, then droping eyes by 100% Estradiol Benzoate parenteral solution four times a day)E.ovariectomy with low-dose estradiol injecting(bilateral oophorectomy, then intramuscular injection by Estradiol Benzoate parenteral solution ,0.200mg.Kg-1, in each three days)F. ovariectomy with high-dose estradiol injecting (bilateral oophorectomy, then intramuscular injection by Estradiol Benzoate parenteral solution ,0.400mg.Kg-1, in each three days)The changes of lenses were observed with naked eye and slit-lamp microscope. After 6 weeks of operation, all rats were killed and serum estradiol levels were determined with radioimmunoassay in each rat. The rats lenses were taken out to observe the cell morphological changes under the light microscope. The expression of estrogen receptorαandβ, and Survivin were observed with SP imunohistochemical technique. The datas were shown by (±S), the satistical analysis was described by SPSS13.0 software.Results:1.Under naked eye and the slit-lamp microscope, there was no different vacuoles, clefts or punctate opacity on lenses found in every group.2.Under the light microscope, there was no difference among each group in lens capsule, lens epithelial cells and lens fiber.3. At the 6 weeks, There was no difference between levels of serum estradiol in Group B,Group C and Group D(P>0.05). Both Group E and Group F were higher than Group B(P<0.05). 4. In imunohistochemical examination, the expression(rate /OD) of ERαand ERβin Group B were less than Group A(P<0.01); Group C,Group D and Group F were higher than Group B(P<0.01); Group F were higher than Group E (P<0.01); There was no difference between Group C, Group D and Group F(P>0.05).5.There was no Survivin in GroupA,B,C and E. However, we can see Survivin in LECs in GroupD and F.Conclusion:1. The expression of ERαand ERβin LECS were related with the level of serum estradiol. Estradiol prevented lens opacity through using ERαand ERβ.2. The expression of Survivin in LECS may be caused by the level of serum exogenous estradiol. Estradiol made Survivin express.3. The effects of estrogen on lens by different medication way were different. Low-dose estradiol eyedropping was the best.